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    Optimal sandblasting conditions for conventional-type yttria-stabilized tetragonal zirconia polycrystals. Okada Masahiro,Taketa Hiroaki,Torii Yasuhiro,Irie Masao,Matsumoto Takuya Dental materials : official publication of the Academy of Dental Materials OBJECTIVE:To assess the influence of sandblasting conditions applied to conventional-type yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) on surface roughness, phase transformation, and biaxial flexural strength. METHODS:Commercially available Y-TZP (Lava Frame, 3M Dental Products) disks were used after sintering (specimen dimensions: 14mm in diameter and 1.2mm in thickness). The surfaces of specimens were ground, and then sandblast treatments were conducted at different pressures (0.20, 0.25, 0.30, 0.35 and 0.40MPa) and distances (1, 5, 10 and 20mm) with 50μm alumina particles. Surface roughness measurements were performed and scanning electron microscopy (SEM) images were taken for surface characterizations. Phase transformation of Y-TZP was identified by X-ray diffraction (XRD). Biaxial flexural strength was measured using the piston-on-three-ball test. RESULTS:The surface roughness increased significantly by increasing the sandblasting pressure, and microcracks were observed at high sandblasting pressure at 0.40MPa. The shortest sandblasting distance (1mm) was not effective to increase the surface roughness compared with other sandblasting distances. A tetragonal to monoclinic phase transformation was observed after grinding. The degree of the phase transformation tended to increase with sandblasting pressure, and significant effect was independent of the sandblasting distance. The biaxial flexural test showed improved mechanical strengths for the samples after sandblasting at 0.20-0.35MPa, with the maximum strength at 0.25MPa. Sandblasting at 0.40MPa decreased the strength as compared with 0.25MPa. SIGNIFICANCE:The surface roughness increased with increasing the sandblasting pressure, whereas there was an optimal sandblasting pressure range to increase biaxial flexural strength of Y-TZP. 10.1016/j.dental.2018.11.009
    Synthesis and characterization of core-shell structural MWNT-zirconia nanocomposites. Lu J,Zang J B,Shan S X,Huang H,Wang Y H Nano letters Core-shell structural MWNT/ZrO2 nanocomposites were successfully prepared by one-step hydrolyzing of MWNT-dispersed ZrOCl2.8H2O aqueous solution. A highly conformal and uniform monoclinic zirconia coating was deposited on MWNTs by this new and simple method, and the thickness of the coating increased with the reaction time. 10.1021/nl801841r
    Interface analysis of titanium and zirconium bone implants. Albrektsson T,Hansson H A,Ivarsson B Biomaterials A thin layer of titanium or zirconium was evaporated onto the surface of a plastic implant which was then inserted in the rabbit tibial metaphysis for six months. The implants and surrounding bone were cut out en bloc and sectioned for phase contrast microscopy, scanning- and transmission-electron microscopy. The intact bone-to-metal interface in the case of titanium revealed a fibrous tissue-free boundary zone with a 200-400 A thick proteoglycan coat immediately adjacent to the titanium oxide. Thereafter collagen filaments were seen and, at approximately 1000 A from the interface, collagen bundles. The tissues surrounding the zirconium-coated implant consisted of a 300-500 A thick proteoglycan layer, followed by a zone with collagen filaments and collagen bundles, not closer to the zirconium oxide than a few thousand A.
    Early detachment of titanium particles from various different surfaces of endosseous dental implants. Franchi M,Bacchelli B,Martini D,Pasquale V De,Orsini E,Ottani V,Fini M,Giavaresi G,Giardino R,Ruggeri A Biomaterials Titanium (Ti) endosseous dental screws with different surfaces (smooth titanium--STi, titanium plasma-sprayed-TPS, alumina oxide sandblasted and acid-etched--Al-SLA, zirconium oxide sandblasted and acid etched--Zr-SLA) were implanted in femura and tibiae of sheep to investigate the biological evolution of the peri-implant tissues and detachment of Ti debris from the implant surfaces in early healing. Implants were not loaded. Sections of the screws and the peri-implant tissues obtained by sawing and grinding were analysed by light microscopy immediately after implantation (time 0) and after 14 days. All samples showed new bone trabeculae and vascularised medullary spaces in those areas where gaps between the implants and host bone were visible. In contrast, no osteogenesis was induced in the areas where the implants were initially positioned in close contact with the host bone. Chips of the pre-existing bone inducing new peri-implant neo-osteogenesis were surrounded by new bone trabeculae. The threads of some screws appeared to be deformed where the host bone showed fractures. Ti granules of 3-60 microm were detectable only in the peri-implant tissues of TPS implants both immediately after surgery and after 14 days, thus suggesting that this phenomenon may be related to the friction of the TPS coating during surgical insertion.
    Edentulous jaws rehabilitation with yttrium-stabilized zirconium dioxide implants: two years follow-up experience. Borgonovo A E,Arnaboldi O,Censi R,Dolci M,Santoro G Minerva stomatologica AIM:The aim of this study was to present authors' two-year clinical experience with Yttrium-stabilized zirconium dioxide implants placed in native bone or regenerated bone. METHODS:Yttrium-stabilized zirconium dioxide implants made of brezirkon (whiteSKY, Bredent medical, Senden, Germany) were used for the treatment of edentulous ridge rehabilitation in the Dental Clinic of the University of Milan (Head of the Department, Prof. F. Santoro). Zirconium dioxide is a highly resistant ceramic material obtained by cleaning zirconium dioxide and zirconium silicate. The implant used in the clinical study featured a conical one piece implant with double cylindrical thread with a sandblasted rough surface. The prosthetic section was smooth. RESULTS:Forty-six implants have been inserted in 18 patients from January 2007 to January 2009, the follow-up period was comprised between 6 and 24 months. The overall success rate was 89%; the success rate in native bone was 97% and 74% in augmented bone. It can be stated that the success rate is comparable to titanium fixtures. CONCLUSION:It would be logical to use a ceramic material for the esthetic regions; zirconium dioxide is particularly suitable since it features tissue friendliness and resistance comparable to titanium. The good mechanical properties, possibility of easy fabrication of the prosthetic restoration and the good integration into the tissue and the esthetics provide perfect preconditions for yttrium-stabilized zirconium dioxide to become the most commonly used material in implant dentistry.
    Response to antiseptic agents of periodontal pathogens in in vitro biofilms on titanium and zirconium surfaces. Sánchez M C,Fernández E,Llama-Palacios A,Figuero E,Herrera D,Sanz M Dental materials : official publication of the Academy of Dental Materials OBJECTIVE:The aim of this study was to develop in vitro biofilms on SLA titanium (Ti-SLA) and zirconium oxide (ZrO) surfaces and to evaluate the effect of antiseptic agents on the number of putative periodontal pathogenic species. METHODS:An in vitro biofilm model was developed on sterile discs of Ti-SLA and ZrO. Three antiseptic agents [chlorhexidine and cetyl-pyridinium-chloride (CHX/CPC), essential oils (EEOOs) and cetyl-peridinium-chloride (CPC)] were applied to 72-h biofilms, immersing discs during 1min in the antiseptic solution, either with or without mechanical disruption. Viable bacteria [colony forming units (CFU/mL)] were measured by quantitative polymerase chain reaction (qPCR) combined with propidium monoazide. A generalized lineal model was constructed to determine the effect of the agents on the viable bacterial counts of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Fusobacterium nucleatum on each surface. RESULTS:The exposure to each antiseptic solution resulted in a statistically significant reductions in the number of viable target species included in the in vitro multi-species biofilm, on both Ti-SLA and ZrO (p<0.001) which was of up to 2 orders for A. actinomycetemcomitans, for P. gingivalis 2 orders on Ti-SLA and up to 3 orders on ZrO and, for F. nucleatum up to 4 orders. No significant differences were found in counts of the tested bacteria between in vitro biofilms formed on both Ti-SLA and ZrO, after topically exposure to the antimicrobial agents whether the application was purely chemical or combined with mechanical disruption. SIGNIFICANCE:A. actinomycetemcomitans, P. gingivalis and F. nucleatum responded similarly to their exposure to antiseptics when grown in multispecies biofilms on titanium and zirconium surfaces, in spite of the described structural differences between these bacterial communities. 10.1016/j.dental.2017.01.013
    Hybrid materials offer new perspectives. Arnetzl G,Arnetzl G V International journal of computerized dentistry Dental materials, especially in restorative dentistry, must not only be cost-effective, they must also meet many other requirements: biocompatibility, durability, excellent shade and light effects, abrasion resistance, hardness, mechanical strength under pressure, chemical resistance, surface density, ease of manufacture, and easy intraoral maintenance.
    Preparation, characterization and in vitro response of bioactive coatings on polyether ether ketone. Durham John W,Allen Matthew J,Rabiei Afsaneh Journal of biomedical materials research. Part B, Applied biomaterials Polyether ether ketone (PEEK) is a highly heat-resistant thermoplastic with excellent strength and elastic modulus similar to human bone, making it an attractive material for orthopedic implants. However, the hydrophobic surface of PEEK implants induces fibrous encapsulation which is unfavorable for stable implant anchorage. In this study, PEEK was coated via ion-beam-assisted deposition (IBAD) using a two-layer design of yttria-stabilized zirconia (YSZ) as a heat-protection layer, and hydroxyapatite (HA) as a top layer to improve osseointegration. Microstructural analysis of the coatings showed a dense, uniform columnar grain structure in the YSZ layer and no delamination from the substrate. The HA layer was found to be amorphous and free of porosities in its as-deposited state. Subsequent heat treatment via microwave energy followed by autoclaving crystallized the HA layer, confirmed by SEM and XRD analysis. An in vitro study using MC3T3 preosteoblast cells showed improved bioactivity in heat-treated sample groups. Cell proliferation, differentiation, and mineralization were analyzed by MTT assay and DNA content, osteocalcin expression, and Alizarin Red S (AR-S) content, respectively. Initial cell growth was increased, and osteogenic maturation and mineralization were accelerated most on coatings that underwent a combined microwave and autoclave heat treatment process as compared to uncoated PEEK and amorphous HA surfaces. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 560-567, 2017. 10.1002/jbm.b.33578
    Hydroxyaptite nanorods patterned ZrO2 bilayer coating on zirconium for the application of percutaneous implants. Zhang Lan,Han Yong,Tan Guoxin Colloids and surfaces. B, Biointerfaces Percutaneous implant requires a tight bond between the underlying dermis of skin and implant surface to prevent epithelial down-growth and infection, while fibroblasts play a key role in the skin-implant integration. In this work, nanorod-shaped hydroxyaptite (HA) with a mean diameter of 70 nm and length of 400 nm was hydrothermally grown on micro-arc oxidized (MAOed) Ca- and P-doped ZrO2 to form a bilayer coating. The hydrothermal formation mechanism of HA nanorods was explored, and the adsorption of total protein on the coating from α-MEM medium containing 10% fetal bovine serum was examined. Employing L-929 cells, the behaviors of fibroblasts on the bilayer coating, including adhesion and proliferation were evaluated together the polished Zr and as-MAOed ZrO2. The obtained results show that the HA nanorods nucleated on ZrO2 and grew at the expense of the doped Ca and P ions during the hydrothermal treatment (HT). The HA nanorods patterned coating enhanced protein absorption, and significantly improved the adhesion and proliferation of fibroblasts compared to the as-MAOed ZrO2 and polished Zr. It suggests that the HA nanorods/ZrO2 coated zirconium has a potential application for percutaneous implants to enhance the attachment of skin. 10.1016/j.colsurfb.2015.01.017
    Silicon Nitride (SiN) Implants: The Future of Dental Implantology? Badran Zahi,Struillou Xavier,Hughes Francis J,Soueidan Assem,Hoornaert Alain,Ide Mark The Journal of oral implantology For decades titanium has been the preferred material for dental implant fabrication, with mechanical and biological performance resulting in high clinical success rates. These have been further enhanced by incremental development of surface modifications aimed at improving speed and degree of osseointegration and resulting in enhanced clinical treatment options and outcomes. However, increasing demand for metal-free dental restorations has also led to the development of ceramic-based dental implants, such as zirconia. In orthopedics, alternative biomaterials, such as polyetheretherketone or silicon nitride, have been used for implant applications. The latter is potentially of particular interest for oral use as it has been shown to have antibacterial properties. In this article we aim to shed light on this particular biomaterial as a future promising candidate for dental implantology applications, addressing basic specifications required for any dental implant material. In view of available preclinical data, silicon nitride seems to have the essential characteristics to be a candidate for dental implants material. This novel ceramic has a surface with potentially antimicrobial properties, and if this is confirmed in future research, it could be of great interest for oral use. 10.1563/aaid-joi-D-16-00146
    The potential role of human osteoblasts for periprosthetic osteolysis following exposure to wear particles. Lochner Katrin,Fritsche Andreas,Jonitz Anika,Hansmann Doris,Mueller Petra,Mueller-Hilke Brigitte,Bader Rainer International journal of molecular medicine Aseptic loosening in total hip replacement is mainly caused by wear particles inducing inflammation and osteolysis. Wear can be a consequence of micromotions at the interface between implant and bone cement. Due to complex cellular interactions, different mediators (e.g. cytokines, proteinases) are released, which can promote osteolytic processes in the periprosthetic tissue followed by loosening of the implant. Furthermore, a reduced matrix synthesis and an induced apoptosis rate can be observed. The purpose of this study was to evaluate to what extent human primary osteoblasts exposed to wear particles are involved in the osteolysis. The viability, the secretion of collagen and collagenases and the variety of released cytokines after particle exposure was examined. Therefore, human osteoblasts were incubated with particles experimentally generated in the interface between hip stems with rough and smooth surface finishings as well as different material compositions (Ti-6Al-7Nb, Co-28Cr-6Mo and 316L) and bone cement mantle made of Palacos R containing zirconium oxide particles. Commercially pure titanium particles, titanium oxide, polymethylmethacrylate and particulate zirconium oxide were used as references. The results revealed distinct effects on the cytokine release of human osteoblasts towards particulate debris. Thereby, human osteoblasts released increased levels of interleukine (IL)-6 and IL-8 after treatment with metallic wear particles. The expression of VEGF was slightly induced by all particle entities at lower concentrations. Apoptotic rates were enhanced for osteoblasts exposed to all the tested particles. Furthermore, the de novo synthesis of type 1 collagen was reduced and the expression of the matrix metalloproteinase (MMP)-1 was considerably increased. However, wear particles of Co-28Cr-6Mo stems seemed to be more aggressive, whereas particles derived from stainless steel stems caused less adverse cellular reaction. Among the reference particles, which caused less altered reactions in the metabolism of osteoblasts in general, ZrO2 can be assumed as the material with the smallest cell biological effects. 10.3892/ijmm.2011.778
    A comparison of biocompatibility and osseointegration of ceramic and titanium implants: an in vivo and in vitro study. Möller B,Terheyden H,Açil Y,Purcz N M,Hertrampf K,Tabakov A,Behrens E,Wiltfang J International journal of oral and maxillofacial surgery This study compared the biocompatibility in vitro and the osseointegration in vivo of zirconium and titanium implants regarding implant surfaces and the bone-implant contacts. The different implant surfaces and the biocompatibility of zirconium versus titanium implants were determined by vitality and cytotoxic tests in vitro. The contact of the osteoblasts to the implant surface was determined by scanning electron microscopy (SEM). The in vivo study for osseointegration was performed in domestic pigs over 4 and 12 weeks. In each animal, 4 zirconium and 4 titanium implants (WhiteSky, BlueSky, Bredent, Germany) were inserted in the os frontale and analysed by histomorphometry. Cytotoxicity and SEM showed good biocompatibility in relation to the investigated implant materials. Histological results showed direct bone-implant contact of the implant surfaces. The zirconium implants showed a slight delay in osseointegration in terms of bone-implant contact as measured by histomorphometry (after 4 weeks, zirconium (59.3 ± 4.6%) versus titanium (64.1 ± 3.9%); after 12 weeks, zirconium (67.1 ± 2.3%) versus titanium (73.6 ± 3.2%). A statistically significant difference between the two groups was not observed. The results indicated similar biocompatibility and osseointegration for zirconium compared to titanium implants. 10.1016/j.ijom.2012.02.004
    Osseointegration of Alkali-Modified NANOZR Implants: An In Vivo Study. Komasa Satoshi,Nishizaki Mariko,Zhang Honghao,Takao Seiji,Yin Derong,Terada Chisato,Kobayashi Yasuyuki,Kusumoto Tetsuji,Yoshimine Shigeki,Nishizaki Hiroshi,Okazaki Joji,Chen Luyuan International journal of molecular sciences Ingredients and surface modification methods are being continually developed to improve osseointegration of dental implants and reduce healing times. In this study, we demonstrate in vitro that, by applying concentrated alkali treatment to NANOZR with strong bending strength and fracture toughness, a significant improvement in the bone differentiation of rat bone marrow cells can be achieved. We investigated the influence of materials modified with this treatment in vivo, on implanted surrounding tissues using polychrome sequential fluorescent labeling and micro-computer tomography scanning. NANOZR implant screws in the alkali-treated group and the untreated group were evaluated after implantation in the femur of Sprague⁻Dawley male rats, indicating that the amount of new bone in the alkali-modified NANOZR was higher than that of unmodified NANOZR. Alkali-modified NANOZR implants proved to be useful for the creation of new implant materials. 10.3390/ijms20040842
    Enhanced effects of nano-scale topography on the bioactivity and osteoblast behaviors of micron rough ZrO2 coatings. Wang Guocheng,Liu Xuanyong,Zreiqat Hala,Ding Chuanxian Colloids and surfaces. B, Biointerfaces Implant surface topography is one of the most important factors affecting the rate and extent of osseointegration. Randomly micron-roughened surfaces have been documented to support osteoblast adhesion, differentiation, and mineralized phenotype, and thus favoring bone fixation of implants to host tissues. However, few studies have been done yet to investigate whether their effects on osteoblast behaviors can be enhanced by incorporation of nano-scale topographic cues. To validate this hypothesis, zirconia coatings with micron roughness (about 6.6 μm) superimposed by nano-sized grains (<50 nm) were fabricated by plasma spraying. To validate the impact of nano-sized grains, post-treatments of surface polishing (SP) and heat treatment (HT) were performed on the as-sprayed (AS) coatings to change the surface topographies but keep the chemical and phase composition similar. Results of in vitro bioactivity test showed that apatite was formed only on coating surfaces with nano-sized grains (AS coatings), indicating the significance of nano-topographic cues on the in vitro bioactivity. Enhanced osteoblast adhesion and higher cell proliferation rate were observed on coatings with both micron-roughness and nano-sized grains (AS-coatings), compared to coatings with smooth surfaces (SP-coatings) and coatings with only micron-scale roughness (heat-treated coatings), indicating the significant effects of nano-size grains on osteoblast responses. As the micron rough surfaces have been well-documented to enhance bone fixation, results of this work suggest that a combination of surface modifications at both micron and nano-scale is required for enhanced osseointegration of orthopedic implants. 10.1016/j.colsurfb.2011.04.006
    Osteogenesis and morphology of the peri-implant bone facing dental implants. Franchi Marco,Orsini Ester,Trire Alessandra,Quaranta Marilisa,Martini Desiree,Piccari Gabriella G,Ruggeri Alessandro,Ottani Vittoria TheScientificWorldJournal This study investigated the influence of different implant surfaces on peri-implant osteogenesis and implant face morphology of peri-implant tissues during the early (2 weeks) and complete healing period (3 months). Thirty endosseous titanium implants (conic screws) with differently treated surfaces (smooth titanium = SS, titanium plasma sprayed = TPS, sand-blasted zirconium oxide = Zr-SLA) were implanted in femur and tibiae diaphyses of two mongrel sheep. Histological sections of the implants and surrounding tissues obtained by sawing and grinding techniques were observed under light microscopy (LM). The peri-implant tissues of other samples were mechanically detached from the corresponding implants to be processed for SEM observation. Two weeks after implantation, we observed osteogenesis (new bone trabeculae) around all implant surfaces only where a gap was present at the host bone-metal interface. No evident bone deposition was detectable where threads of the screws were in direct contact with the compact host bone. Distance osteogenesis predominated in SS implants, while around rough surfaces (TPS and Zr-SLA), both distance and contact osteogenesis were present. At SEM analysis 2 weeks after implantation, the implant face of SS peri-implant tissue showed few, thin, newly formed, bone trabeculae immersed in large, loose, marrow tissue with blood vessels. Around the TPS screws, the implant face of the peri-implant tissue was rather irregular because of the rougher metal surface. Zr-SLA screws showed more numerous, newly formed bone trabeculae crossing marrow spaces and also needle-like crystals in bone nodules indicating an active mineralising process. After 3 months, all the screws appeared osseointegrated, being almost completely covered by a compact, mature, newly formed bone. However, some marrow spaces rich in blood vessels and undifferentiated cells were in contact with the metal surface. By SEM analysis, the implant face of the peri-implant tissue showed different results. Around the SS screws, the compact bone with areas of different mineralisation rate appeared very smooth, while around the rougher TPS screws, the bone still showed an irregular surface corresponding to the implant macro/microroughness. Around the Zr-SLA screws, a more regular implant-bone surface and sparse, calcified marrow spaces were detectable. Results from this research suggest that 2 weeks after implantation, trabecular bone represents the calcified healing tissue, which supports the early biological fixation of the implants. The peri-implant marrow spaces, rich in undifferentiated cells and blood vasculature, observed both 2 weeks and 3 months after surgery, favour the biological turnover of both early and mature peri-implant bone. The implant surface morphology strongly influences the rate and the modality of peri-implant osteogenesis, as do the morphology and arrangement of the implant face in peri-implant bone both during early healing (after 2 weeks) and when the implant is just osseointegrated; rough surfaces, and in particular Zr-SLA, seem to better favour bone deposition on the metal surface. 10.1100/tsw.2004.211
    Osteointegration of bioactive glass-coated and uncoated zirconia in osteopenic bone: an in vivo experimental study. Aldini N Nicoli,Fini M,Giavaresi G,Martini L,Dubini B,Ponzi Bossi M G,Rustichelli F,Krajewski A,Ravaglioli A,Mazzocchi M,Giardino R Journal of biomedical materials research. Part A In elderly and osteoporotic patients an age-related loss of osteoinductivity could be the biological cause of implant failure regardless of the high quality of the implanted device. yttria stabilized tetragonal zirconia (YSTZ), either coated with the bioactive glass named RKKP bioglaze (RKKP) or uncoated, was implanted in the distal femurs of sham-operated and ovariectomized female rats. Animals were sacrificed at 30 and 60 days. Histomorphometry and microhardness tests were performed to assess osteointegration rate as well as bone quality around the implants. Significant decreases (p < 0.0005) in trabecular bone volume, BV/TV (41%), trabecular bone surface BS/TV (33%), trabecular thickness Tb.Th (20%), and trabecular number Tb.N (32%), together with a significant increase in trabecular separation Tb.Sp (184%), were found for the osteopenic rats compared with the sham-operated rats. At both experimental times the RKKP coating ensured a better osteointegration rate with higher AI values than the uncoated YSTZ, even when osteopenic rats were used (48% at 30 days and 12% at 60 days). No differences were observed at the bone-biomaterial interfaces for either material when comparing sham-operated with osteopenic rats. The present results demonstrate that the RKKP bioactive glass used as a coating ensures a high osteointegration rate even in osteoporotic bone, which is already visible from postoperative day 30 and is still apparent on day 60. 10.1002/jbm.a.20057
    Osseointegration of implants with dendrimers surface characteristics installed conventionally or with Piezosurgery®. A comparative study in the dog. Bengazi Franco,Lang Niklaus P,Canciani Elena,Viganò Paolo,Velez Joaquin Urbizo,Botticelli Daniele Clinical oral implants research AIM:The first aim of the present experiment was to compare bone healing at implants installed in recipient sites prepared with conventional drills or a piezoelectric device. The second aim was to compare implant osseointegration onto surfaces with and without dendrimers coatings. MATERIAL AND METHODS:Six Beagles dogs were used in this study. Five implants with two different surfaces, three with a ZirTi(®) surface (zirconia sand blasted, acid etched), and two with a ZirTi(®)-modified surface with dendrimers of phosphoserine and polylysine were installed in the right side of the mandible. In the most anterior region (P2, P3), two recipient sites were prepared with drills, and one implant ZirTi(®) surface and one coated with dendrimers implants were installed at random. In the posterior region (P4 and M1), three recipient sites were randomly prepared: two sites with a Piezosurgery(®) instrument and one site with drill and two ZirTi(®) surface and one coated with dendrimers implants installed. Three months after the surgery, the animals were sacrificed for histological analysis. RESULTS:No complications occurred during the healing period. Three implants were found not integrated and were excluded from analysis. However, n = 6 was obtained. The distance IS-B at the buccal aspect was 2.2 ± 0.8 and 1.8 ± 0.5 mm, while IS-C was 1.5 ± 0.9 and 1.4 ± 0.6 mm at the Piezosurgery(®) and drill groups, respectively. Similar values were obtained between the dendrimers-coated and ZirTi(®) surface implants. The BIC% values were higher at the drill (72%) compared to the Piezosurgery(®) (67%) sites. The BIC% were also found to be higher at the ZirTi(®) (74%) compared to the dendrimers-coated (65%) implants, the difference being statistically significant. CONCLUSION:This study has revealed that oral implants may osseointegrate equally well irrespective of whether their bed was prepared utilizing conventional drills with abundant cooling or Piezosurgery(®). Moreover, the surface coating of implants with dendrimers phosphoserine and polylysine did not improve osseointegration. 10.1111/clr.12082
    Five-year follow-up of implant-supported Y-TZP and ZTA fixed dental prostheses. A randomized, prospective clinical trial comparing two different material systems. Larsson Christel,Vult von Steyern Per The International journal of prosthodontics PURPOSE:The aim of this study was to evaluate the clinical performance of two- to five-unit implant-supported all-ceramic restorations and to compare the results of two different all-ceramic systems, Denzir (DZ) and In-Ceram Zirconia (InZ). MATERIALS AND METHODS:Eighteen patients were treated with a total of 25 two- to five-unit implant-supported fixed dental prostheses. Nine patients were given DZ system restorations and 9 were given InZ system restorations. The restorations were cemented with zinc phosphate cement onto customized titanium abutments and were evaluated after 1, 3, and 5 years. RESULTS:At the 5-year follow-up, all restorations were in function; none had fractured. However, superficial cohesive (chip-off) fractures were observed in 9 of 18 patients (11 of 25 restorations). Sixteen units in the DZ group (9 of 13 restorations) and 3 in the InZ group (2 of 12 restorations) had chip-off fractures. The difference between the two groups regarding frequency of chip-off fractures was statistically significant (P < .05 at the FDP level and P < .001 at the unit level). CONCLUSION:The results suggest that all-ceramic implant-supported fixed dental prostheses of two to five units may be considered a treatment alternative. The DZ system, however, exhibited an unacceptable amount of veneering porcelain fractures and thus cannot be recommended for the type of treatment evaluated in this trial. Poor compatibility or problems with the bond mechanisms between the veneer and framework could not explain the chip-off fractures. Stress distribution, as well as other factors concerning the veneering porcelain, need to be evaluated further.
    Innovations in dental implant design for current therapy. Lesmes Daniel,Laster Zvi Oral and maxillofacial surgery clinics of North America The use of osseointegrated dental implants has gained momentum, mainly in the last 20 years. Research and development in the field of implantology are constantly focusing on implant redesign to continue to try and improve implant success. The current aim of implant design is to address situations prone to failure, such as cases of low bone quality or cases of concomitant systemic diseases that compromise healing. 10.1016/j.coms.2011.02.001
    Osseointegration and clinical success of zirconia dental implants: a systematic review. Wenz Hans J,Bartsch Johannes,Wolfart Stefan,Kern Matthias The International journal of prosthodontics PURPOSE:Various ceramic implant systems made of yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) have become commercially available in recent years. A systematic search of the literature was performed to assess the clinical success of dental Y-TZP implants and whether the osseointegration of Y-TZP is comparable to that of titanium, the standard implant material. MATERIALS AND METHODS:The internet database MEDPILOT was searched cumulatively for the keywords zircon* and dent* and implant as well as for zircon* and osseointegration. The last search was conducted on January 31st, 2007. Subsequently, the reference lists of the relevant publications were searched. Furthermore, a letter was sent to the 5 identified manufacturers of zirconia dental implants to ask for peer-reviewed publications. RESULTS:Ninety-six articles were found by the search strategy. No controlled clinical studies in humans regarding clinical outcomes or osseointegration could be identified. Clinical data were restricted to case studies and case series. Only 7 animal studies fulfilled the inclusion criteria. Osseointegration was evaluated at 4 weeks to 24 months after placement in different animal models and sites and under different loading conditions. The mean bone-implant contact percentage was above 60% in almost all experimental groups. In studies that used titanium implants as a control, Y-TZP implants were comparable to or even better than titanium implants. Surface modifications may further improve initial bone healing and resistance to removal torque. CONCLUSIONS:Y-TZP implants may have the potential to become an alternative to titanium implants but cannot currently be recommended for routine clinical use, as no long-term clinical data are available.
    Bone healing at implants with different surface configurations: an experimental study in dogs. Beolchini Marco,Lang Niklaus P,Gómez Moreno Gerardo,Iezzi Giovanna,Botticelli Daniele,Calvo Guirado José Luis Clinical oral implants research OBJECTIVE:To study osseointegration of implants with surface modifications by the use of fluoroboric acid and/or H2 O2 installed in conventional sites or sites with circumferential marginal defects. MATERIAL AND METHODS:Four implants with different surfaces were used. One basic surface (ZirTi(®)) was sandblasted with zirconium microspheres and acid etched additionally with hydrofluoric acid. A second surface was treated with fluoroboric acid instead of hydrofluoric acid. The remainder of the other two surfaces was additionally treated with H2O2. The edentulous mandibles of 6 foxhound dogs were used to randomly install 8.5-mm-long implants with the different surfaces and to study the histological healing after 1 and 3 months. To study osteoconductivity, additional four recipient sites were prepared with the coronal region being widened so that a 4 mm deep and 0.85 mm wide marginal defect resulted after the placement of the four implants with different surfaces. No filler material or membranes were used, and a fully submerged healing was allowed for 3 months. RESULTS:At the conventional sites, new bone formation ranged between 68.5% and 74.9% after 1 month. After 3 months, bone-to-implant contact ranged from 72.6% at the ZirTi(®) surface to 84.1% at the fluoroboric acid-treated implants, the difference being statistically significant. At the sites with marginal defects, bone formation ranged from 0.77 mm at the surface treated with fluoroboric acid and H2O2 , to 1.93 mm at the surface treated with fluoroboric acid alone. CONCLUSIONS:Fluoroboric acid treatment alone of titanium implant surfaces resulted in improved osseointegration and osteoconductivity after 3 months. 10.1111/clr.12562
    Peripheral quantitative computer tomographic, histomorphometric, and removal torque analyses of two different non-coated implants in a rabbit model. Shin Daniel,Blanchard Steven B,Ito Michio,Chu Tien-Min G Clinical oral implants research OBJECTIVE:The objectives of this study were (1) to investigate the bone-tissue response to zirconia and titanium implants at the implant-to-bone interface and at the periosteal level and (2) to quantitatively measure the mineral density of the peri-implant bone using peripheral quantitative computer tomography (pQCT). MATERIAL AND METHODS:Ten 3.5 mm × 6.6 mm screw-shaped threaded implants fabricated from titanium and zirconia were inserted into the mid-tibial diaphysis of five male New Zealand white rabbits. Calcein green was administered at 4 weeks post-implantation. The animals were sacrificed after 6 weeks and implants were retrieved and analyzed in terms of bone-to-implant contact (BIC), bone area (BA), mineralized surface (MS) percentage, inter-thread calcein labels, removal torque (RT) values, as well as pQCT measurements. FINDINGS:No statistically significant differences were detected between the zirconia and titanium implants in terms of BIC, RT, and pQCT. However, statistically significant higher BA and MS levels were found in the titanium group, while the higher amount of calcein labels occupying the threads were found in the zirconium group. Significant differences were also found in the quantity and the composition of bone at the bone-implant interfacial area vs. the region 1.5 mm away from the bone-implant interface, irrespective of the implant type. CONCLUSION:Zirconia implants demonstrated a lower bone remodeling activity in the periosteal region. The bone at the bone-implant interface shows a significantly lower cortical bone density, a higher trabecular density, and trabecular mineral content. Finally, zirconia and titanium implants showed similar bone-implant responses in terms of BIC and RT. 10.1111/j.1600-0501.2010.01980.x
    Surface contamination of dental implants assessed by gene expression analysis in a whole-blood in vitro assay: a preliminary study. Harder Sönke,Quabius Elgar S,Ossenkop Lars,Mehl Christian,Kern Matthias Journal of clinical periodontology AIM:We aimed at evaluating pyrogen contamination of dental implants made of titanium and zirconia by using gene expression analysis in a whole-blood in vitro assay. MATERIAL AND METHODS:Titanium and zirconia implants (five each) were incubated in human whole blood. Samples were assayed for gene expression levels of toll-like receptor 4 (TLR4), TLR9, interleukin (IL)-1β, nuclear factor 'kappa-light-chain-enhancer' of activated B-cells (NF-kB), tumour necrosis factor (TNF)-α, and Fas-associated protein with death domain (FADD) as indicators of surface contamination resulting in lipopolysaccharides (LPS)-stimulated TLR- or TNF-mediated immune responses. Gene expression was assayed using real-time quantitative polymerase chain reaction (RT-qPCR). Non-stimulated blood from the same donor served as a negative control, and blood stimulated with LPS served as a positive control. After dry-heat treatment with dry heat, all implants were re-analysed as described above. RESULTS:Both implant systems contained surface contaminants evoking a pro-inflammatory response similar to that induced by LPS. After dry-heat treatment, gene expression was significantly decreased to levels similar to those of negative control samples. CONCLUSIONS:The results demonstrated LPS-like surface-bound contaminants in both tested implant systems. Depyrogenation with dry heat seems to be an effective means of reducing such contamination in dental implants. 10.1111/j.1600-051X.2012.01929.x
    Bone response to free-form fabricated hydroxyapatite and zirconia scaffolds: a transmission electron microscopy study in the human maxilla. Grandfield Kathryn,Palmquist Anders,Ericson Fredric,Malmström Johan,Emanuelsson Lena,Slotte Christer,Adolfsson Erik,Botton Gianluigi A,Thomsen Peter,Engqvist Håkan Clinical implant dentistry and related research BACKGROUND:Understanding the interfacial reactions to synthetic bone regenerative scaffolds in vivo is fundamental for improving osseointegration and osteogenesis. Using transmission electron microscopy, it is possible to study the biological response of hydroxyapatite (HA) and zirconia (ZrO(2) ) scaffolds at the nanometer scale. PURPOSE:In this study, the bone-bonding abilities of HA and ZrO(2) scaffolds produced by free-form fabrication were evaluated in the human maxilla at 3 months and 7 months. MATERIALS AND METHODS:HA and ZrO(2) scaffolds (ø: 3 mm) were implanted in the human maxilla, removed with surrounding bone, embedded in resin, and sectioned. A novel focused ion beam (FIB) sample preparation technique enabled the production of thin lamellae for study by scanning transmission electron microscopy. RESULTS:Interface regions were investigated using high-angle annular dark-field imaging and energy-dispersive X-ray spectroscopy analysis. Interfacial apatite layers of 80 nm and 50 nm thickness were noted in the 3- and 7-month HA samples, respectively, and bone growth was discovered in micropores up to 10 µm into the samples. CONCLUSIONS:The absence of an interfacial layer in the ZrO(2) samples suggest the formation of a direct contact with bone, while HA, which bonds through an apatite layer, shows indications of resorption with increasing implantation time. This study demonstrates the potential of HA and ZrO(2) scaffolds for use as bone regenerative materials. 10.1111/j.1708-8208.2009.00270.x
    Post-thermocycling shear bond strength of a gingiva-colored indirect composite layering material to three implant framework materials. Komine Futoshi,Koizuka Mai,Fushiki Ryosuke,Taguchi Kohei,Kamio Shingo,Matsumura Hideo Acta odontologica Scandinavica OBJECTIVE:To evaluate shear bond strength of a gingiva-colored indirect composite to three implant framework materials, before and after thermocycling, and verify the effect of surface pre-treatment for each framework. MATERIALS AND METHODS:Commercially pure titanium (CP-Ti), American Dental Association (ADA) type 4 casting gold alloy (Type IV) and zirconia ceramics (Zirconia) were assessed. For each substrate, 96 disks were divided into six groups and primed with one of the following primers: Alloy Primer (ALP), Clearfil Photo Bond (CPB), Clearfil Photo Bond with Clearfil Porcelain Bond Activator (CPB+Activator), Estenia Opaque Primer (EOP), Metal Link (MLP) and V-Primer (VPR). The specimens were then bonded to a gingiva-colored indirect composite (Ceramage Concentrate GUM-D). Shear bond strengths were measured at 0 and 20 000 thermocycles and data were analyzed with the Steel-Dwass test and Mann-Whitney U-test. RESULTS:Shear bond strengths were significantly lower after thermocycling, with the exception of Type IV specimens primed with CPB (p = 0.092) or MLP (p = 0.112). For CP-Ti and Zirconia specimens, priming with CPB or CPB+Activator produced significantly higher bond strengths at 0 and 20 000 thermocycles, as compared with the other groups. For Type IV specimens, priming with ALP or MLP produced higher bond strengths at 0 and 20 000 thermocycles. CONCLUSIONS:Shear bond strength of a gingiva-colored indirect composite to CP-Ti, gold alloy and zirconia ceramics was generally lower after thermocycling. Application of a hydrophobic phosphate monomer and polymerization initiator was effective in maintaining bond strength of CP-Ti and zirconia ceramics. Combined use of a thione monomer and phosphoric monomer enhanced the durable bond strength of gold alloy. 10.3109/00016357.2012.741710
    Surface alterations of several dental materials by a novel ultrasonic scaler tip. Seol Hyon-Woo,Heo Seong-Joo,Koak Jai-Young,Kim Seong-Kyun,Baek Seung-Ho,Lee Su-Young The International journal of oral & maxillofacial implants PURPOSE:To assess the effects of a recently developed ultrasonic scaler tip, composed mainly of copper, on the surfaces of several dental materials. MATERIALS AND METHODS:Representative samples of dental materials, including titanium, type II gold, cobalt-chromium alloy, zirconia, and porcelain, were prepared. Three ultrasonic scaler tips of conventional metal (CM), carbon composite (CC), and copper alloy (CA) were prepared. To simulate ultrasonic scaling in an oral environment, 30 g of force was applied using a double-pan balance, and the scaler tip was allowed to move horizontally 5 mm for three consecutive cycles of 20 seconds each. The power of the scaler tip was set to intermediate according to the manufacturer's advice. The surface morphology of each dental material was examined using scanning electron microscopy and confocal laser scanning microscopy. Statistical analysis was performed through one-way analysis of variance and post hoc Scheffé test. All values were considered significant when P < .05. RESULTS:Surface alterations of titanium, type II gold, and cobalt-chromium alloy by the CM tip were much greater than those caused by the CC and CA tips. No alterations were created on the zirconia surface by the CM, CC, or CA tips. On the porcelain surface, surface roughness (Ra) induced by the CM tip was 1.86 and 1.72 times higher than that produced by the CC and CA tips, respectively (P < .001). CONCLUSIONS:Within the limitations of this study, the surface alterations induced by CC and CA tips on the surfaces of dental materials were comparable. Therefore, this novel ultrasonic copper alloy scaler tip may possibly be used for the maintenance of implant prostheses.
    Ceramic implants (Y-TZP): are they a viable alternative to titanium implants for the support of overdentures? A randomized clinical trial. Osman Reham B,Swain Michael V,Atieh Momen,Ma Sunyoung,Duncan Warwick Clinical oral implants research OBJECTIVE:The objective of this study was to assess 1-year clinical success of one-piece zirconia implants compared with similar-design titanium implants, in the context of a novel protocol for implant distribution. MATERIALS AND METHODS:Twenty-four edentulous participants were randomly allocated to one-piece titanium or zirconia implant group. Each participant received four implants in the maxilla (mid-palatal and three anterior crestal implants) and three implants in the mandible (mid-symphyseal and two bilateral distal implants). Conventional loading protocol was followed. Marginal bone remodeling and clinical success of implants were evaluated. The data were statistically analyzed, and risk predictors for implant failures were evaluated. RESULTS:There was no significant difference in the survival rate between the two groups. In the mandible, the survival rate of titanium implants was 95.8% vs. 90.9% for the zirconia implants. The corresponding values in the maxilla were 71.9% and 55%, respectively. Three implants in the zirconia group fractured. Statistically significant less marginal bone loss was observed around titanium implants (0.18 mm) compared with the zirconia group (0.42 mm). The prediction model revealed a higher risk for implant failures in the maxilla (P < 0.0001). CONCLUSION:The outcome of this study indicates caution before recommendation can be made for the use of single-piece zirconia implants for overdenture support. Their use should be limited to cases with proven allergy to titanium. This is mainly due to the increased bone loss and higher fracture rate observed for zirconia implants. Future biomaterial research should focus on producing surface characteristics on zirconia implants with outcomes similar to those established for the optimum osseointegration of titanium implants. 10.1111/clr.12272
    Full-mouth oral rehabilitation in a titanium allergy patient using zirconium oxide dental implants and zirconium oxide restorations. A case report from an ongoing clinical study. Oliva Xavi,Oliva Josep,Oliva Josep D The European journal of esthetic dentistry : official journal of the European Academy of Esthetic Dentistry This case report describes the full-mouth oral rehabilitation of a titanium allergic patient. The patient was a young female with amelogenesis imperfecta who had generalized massive tooth destruction. All teeth in the mouth were extracted and 15 CeraRoot acid-etched (ICE surface) implants were placed (seven implants in the maxilla and eight implants in the mandible). No immediate temporaries were placed. Temporaries were placed 3 months after surgery, and left in function for 2 months. The case was finally restored with zirconium oxide bridges and ceramic veneering (three bridges in the maxilla and another three in the mandible). The 3-year follow-up showed good stability of soft tissues and bone level. Zirconium oxide implants and restorations might be an alternative for the oral rehabilitation of titanium allergic patients.
    Effects of CO2 laser irradiation on the surface properties of magnesia-partially stabilised zirconia (MgO-PSZ) bioceramic and the subsequent improvements in human osteoblast cell adhesion. Hao L,Lawrence J,Chian K S Journal of biomaterials applications In order to acquire the surface properties favouring osseo-integration at the implant and bone interface, human foetal osteoblast cells (hFOB) were used in an in vitro test to examine changes in cell adhesion on a magnesia-partially stabilised zirconia (MgO-PSZ) bioceramic after CO(2) laser treatment. The surface roughness, microstructure, crystal size and surface energy of untreated and CO(2) laser-treated MgO-PSZ were fully characterised. The in vitro cell evaluation revealed a more favourable cell response on the CO(2) laser-treated MgO-PSZ than on the untreated sample. After 24-h cell incubation, no cell was observed on the MgO-PSZ, whereas a few cells attached on the CO(2) laser-treated MgO-PSZandshowedwellspreadandgood attachment. Moreover, the cell coverage density indicating cell proliferation generally increases with CO(2) laser power densities applied in the experiments. The enhancement of the surface energy of the MgO-PSZ, especially its polar component caused by the CO(2) laser treatment, was found to play a significant role in the initial cell attaching, thus enhancing the cell growth. Moreover, the change in topography induced by the CO(2) laser treatment was identified as one of the factors influencing the hFOB cell response. 10.1177/0885328204043546
    Osseointegration of zirconia and titanium dental implants: a histological and histomorphometrical study in the maxilla of pigs. Gahlert M,Röhling S,Wieland M,Sprecher C M,Kniha H,Milz S Clinical oral implants research OBJECTIVES:The purpose of the present study was to histologically compare the bone tissue responses to surface-modified zirconia and titanium implants. METHODS:Threaded zirconia implants were produced using a new low-pressure injection moulding technique and thereafter surface treated by acid etching. Titanium implants with the exact shape and surface treated by sandblasting and acid etching (SLA) served as controls. Fifteen adult pigs received both implant types in the maxilla 6 months after extraction of the second and third incisors. The animals were sacrificed after 4, 8 and 12 weeks and 30 implants with surrounding bone were retrieved. RESULTS:Histological evaluation showed osseous integration for both materials. Zirconia implants revealed mean peri-implant bone density values of 42.3% (SD +/- 14.5) at 4 weeks, 52.6% (SD +/- 5.7) at 8 weeks and 54.6% (SD +/- 11.5) at 12 weeks after implantation, whereas Ti-SLA implants demonstrated mean values of 29% (SD +/- 10), 44.1% (SD +/- 18) and 51.6% (SD +/- 8.6) at corresponding time intervals. With respect to the bone-implant contact ratio, the mean values for zirconia ranged between 27.1% (SD +/- 3.5) and 51.1% (SD +/- 12.4) and for Ti-SLA, it ranged between 23.5% (SD +/- 7.5) and 58.5% (SD +/- 11.4). For the parameters investigated, no statistically significant differences between both types of implants could be detected at any time point. CONCLUSIONS:No statistical difference between implants could be demonstrated with any of the methods used. The limited number of animals per group, however, does not allow to conclude that there is no difference in osseointegration between the two types of implants, although the data tend to suggest such a trend. 10.1111/j.1600-0501.2009.01734.x
    Biomechanical comparison of different surface modifications for dental implants. Ferguson Stephen J,Langhoff Jens D,Voelter Katrin,von Rechenberg Brigitte,Scharnweber Dieter,Bierbaum Susanne,Schnabelrauch Matthias,Kautz Armin R,Frauchiger Vinzenz M,Mueller Thomas L,van Lenthe G Harry,Schlottig Falko The International journal of oral & maxillofacial implants PURPOSE:A satisfactory clinical outcome in dental implant treatment relies on primary stability for immediate load bearing. While the geometric design of an implant contributes to mechanical stability, the nature of the implant surface itself is also critically important. Biomechanical and microcomputerized tomographic evaluation of implant osseointegration was performed to compare alternative structural, chemical and biochemical, and/or pharmaceutical surface treatments applied to an identical established implant design. MATERIALS AND METHODS:Dental implants with the same geometry but with 6 different surface treatments were tested in vivo in a sheep model (pelvis). Peri-implant bone density and removal torque were compared at 2, 4, and 8 weeks after implantation. Implant surfaces tested were: sandblasted and acid-etched titanium (Ti), sandblasted and etched zirconia, Ti coated with calcium phosphate (CaP), Ti modified via anodic plasma-chemical treatment (APC), bisphosphonate-coated Ti (Ti + Bisphos), and Ti coated with collagen containing chondroitin sulfate (CS). RESULTS:All dental implants were well integrated at the time of sacrifice. There were no significant differences observed in peri-implant bone density between implant groups. After 8 weeks of healing, removal torque values for Ti, Ti + CaP, Ti + Bisphos, and Ti + collagen + CS were significantly higher than those for zirconia and Ti + APC. CONCLUSIONS:Whereas the sandblasted/acid-etched Ti implant can still be considered the reference standard surface for dental implants, functional surface modifications such as bisphosphonate or collagen coating seem to enhance early peri-implant bone formation and should be studied further.
    The interaction of osteoblasts with bone-implant materials: 1. The effect of physicochemical surface properties of implant materials. Kubies D,Himmlová L,Riedel T,Chánová E,Balík K,Douděrová M,Bártová J,Pešáková V Physiological research This comparative study of various surface treatments of commercially available implant materials is intended as guidance for orientation among particular surface treatment methods in term of the cell reaction of normal human osteoblasts and blood coagulation. The influence of physicochemical surface parameters such as roughness, surface free energy and wettability on the response of human osteoblasts in the immediate vicinity of implants and on the blood coagulation was studied. The osteoblast proliferation was monitored and the expression of tissue mediators (TNF-alpha, IL-8, MMP-1, bone alkaline phosphatase, VCAM-1, TGF-beta) was evaluated after the cell cultivation onto a wide range of commercially available materials (titanium and Ti6Al4V alloy with various surface treatments, CrCoMo alloy, zirconium oxide ceramics, polyethylene and carbon/carbon composite). The formation of a blood clot was investigated on the samples immersed in a freshly drawn whole rabbit blood using scanning electron microscope. The surfaces with an increased osteoblast proliferation exhibited particularly higher surface roughness (here R(a) 3.5 microm) followed by a high polar part of the surface free energy whereas the effect of wettability played a minor role. The surface roughness was also the main factor regulating the blood coagulation. The blood clot formation analysis showed a rapid coagulum formation on the rough titanium-based surfaces. The titanium with an etching treatment was considered as the most suitable candidate for healing into the bone tissue due to high osteoblast proliferation, the highest production of osteogenesis markers and low production of inflammatory cytokines and due to the most intensive blood clot formation. 10.33549/physiolres.931882
    Hard and soft tissue responses to implant made of three different materials with microgrooved collar in a dog model. Igarashi Kensuke,Nakahara Ken,Kobayashi Eizaburo,Watanabe Fumihiko,Haga-Tsujimura Maiko Dental materials journal The objective of the present study was to assess hard and soft tissue around dental implants made of three different materials with microgrooves on the collar surface. Microgrooved implants were inserted in the mandibles of five male beagles. Implants were made of three kinds of material; titanium (Ti), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and ceria partially stabilized zirconia/alumina nanocomposite (Ce-TZP/AlO). The animals were euthanatized at three months after implantation, and harvested tissue was analyzed by means of histology. All kinds of implant were osseointegrated, and there were no significant differences in any histomorphometric parameters among the three groups of microgrooved implants made of different materials. Within the limitations of this study, implants with microgrooves integrated into the surrounding bone tissue, without statistically significant differences among the three tested materials, Ti, Y-TZP, and Ce-TZP/AlO. 10.4012/dmj.2017-197
    Posterior atrophic jaws rehabilitated with prostheses supported by 5 x 5 mm implants with a novel nanostructured calcium-incorporated titanium surface or by longer implants in augmented bone. One-year results from a randomised controlled trial. Pistilli Roberto,Felice Pietro,Piattelli Maurizio,Gessaroli Manlio,Soardi Elisa,Barausse Carlo,Buti Jacopo,Corvino Valeria European journal of oral implantology PURPOSE:To evaluate whether 5 × 5 mm dental implants with a novel nanostructured calciumincorporated titanium surface could be an alternative to implants at least 10 mm long placed in bone augmented with bone substitutes in posterior atrophic jaws. MATERIALS AND METHODS:A total of 40 patients with atrophic posterior (premolar and molar areas) mandibles having 5 to 7 mm of bone height above the mandibular canal and 40 patients with atrophic maxillae having 4 to 6 mm below the maxillary sinus, were randomised according to a parallel group design to receive one to three 5 mm implants or one to three at least 10 mm-long implants in augmented bone at two centres. All implants had a diameter of 5 mm. Mandibles were vertically augmented with interpositional bovine bone blocks and resorbable barriers. Implants were placed after 4 months. Maxillary sinuses were augmented with particulated porcine bone via a lateral window covered with resorbable barriers and implants were placed simultaneously. All implants were submerged and loaded after 4 months with provisional prostheses. Four months later, definitive screw-retained or provisionally cemented metal-ceramic or zirconia prostheses were delivered. Patients were followed up to 1 year post-loading and the outcome measures were prosthesis and implant failures, any complications and peri-implant marginal bone level changes. RESULTS:One maxillary grafted patient dropped out before the 1-year evaluation. In mandibles, 1 grafted patient did not want to go ahead with the treatment because of multiple complications and graft failure, and another grafted patient did not receive his prostheses due the loss of 2 implants. In maxillae, one 5 × 5 mm implant failed with its provisional crown 3 months post-loading. There were no statistically significant differences in prostheses and implant failures. Significantly more complications occurred at both mandibular and maxillary grafted sites: 17 augmented patients were affected by complications versus 8 patients treated with short implants in the mandible (P = 0.0079; difference in proportion = -0.45; 95% CI -0.67 to -0.15), and 5 sinus-lift patients versus none treated with maxillary short implants (P = 0.047; difference in proportion = -0.25; 95% CI -0.44 to -0.06). Patients with mandibular short implants lost on average 0.94 mm of peri-implant bone at 1 year and patients with 10 mm or longer mandibular implants lost 1.03 mm. Patients with maxillary short implants lost on average 0.87 mm of peri-implant bone at 1 year and patients with 10 mm or longer maxillary implants lost 1.15 mm. There were no statistically significant differences in bone level changes up to 1 year between short and longer implants in maxillae (mean difference -0.28 mm, 95% CI -0.56 to 0.01, P = 0.051) and in mandibles (mean difference -0.09 mm, 95% CI -0.26 to 0.08, P = 0.295). CONCLUSIONS:One year after loading, 5 × 5 mm implants achieved similar results compared to longer implants placed in augmented bone. Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster, cheaper and associated with less morbidity, however 5 to 10 years of post-loading data are necessary before making reliable recommendations. CONFLICT-OF-INTEREST STATEMENT:MegaGen partially supported this trial and donated implants and prosthetic components used in this study, whereas Tecnoss donated the biomaterials. The data belonged to the authors and by no means did the manufacturers interfere with the conduct of the trial or the publication of its results.
    Posterior atrophic jaws rehabilitated with prostheses supported by 5 × 5 mm implants with a nanostructured calcium-incorporated titanium surface or by longer implants in augmented bone. Five-year results from a randomised controlled trial. Esposito Marco,Barausse Carlo,Pistilli Roberto,Piattelli Maurizio,Di Simone Salvatore,Ippolito Daniela Rita,Felice Pietro International journal of oral implantology (Berlin, Germany) PURPOSE:To evaluate whether 5 × 5 mm dental implants with a novel nanostructured calcium-incorporated titanium surface could be an alternative to implants at least 10-mm long placed in bone augmented with bone substitutes in posterior atrophic jaws. MATERIALS AND METHODS:Forty patients with atrophic posterior (premolar and molar areas) mandibles having 5- to 7-mm bone height above the mandibular canal, and 40 patients with atrophic maxillae having 4- to 6-mm bone height below the maxillary sinus, were randomised according to a parallel-group design to receive one to three 5-mm implants or one to three at least 10-mm long implants in augmented bone at two centres. All implants had a diameter of 5 mm. Mandibles were vertically augmented with interpositional bovine bone blocks covered with resorbable barriers. Implants were placed after 4 months. Maxillary sinuses were augmented with particulated porcine bone via a lateral window covered with resorbable barriers and implants were placed simultaneously. All implants were submerged and loaded after 4 months with provisional prostheses. Four months later, definitive screw-retained or provisionally cemented metal-ceramic or zirconia prostheses were delivered. Patients were followed to 5 years post-loading and the outcome measures were: prosthesis and implant failures, any complication and peri-implant marginal bone level changes. RESULTS:Sixteen patients dropped out before the 5-year evaluation (four short mandibles, three short maxillae, six augmented mandibles and three augmented maxillae). In mandibles, two grafted patients were not prosthetically rehabilitated because of multiple complications, and three implants failed in the same patient (one was a replacement implant) versus one patient who lost his short implant and crown 2 years after loading. In maxillae one short implant failed with its provisional crown 3 months post-loading. There were no statistically significant differences in prostheses (difference in proportion = -0.003; 95% CI: -0.14 to 0.13; P = 1.000) and implant failures (difference in proportion = -0.03; 95% CI: -0.17 to 0.09; P = 0.609) up to 5 years after loading. Significantly more complications occurred at mandibular grafted sites: 17 augmented patients were affected by complications versus nine patients treated with short implants in mandibles (difference in proportion = 0.39; 95% CI: 0.10 to 0.62; P = 0.013). In the maxilla seven sinus-elevated patients versus two patients treated with short implants were affected by complications, the difference not being statistically significant (difference in proportion = 0.25; 95% CI: -0.04 to 0.49; P = 0.128). Patients with mandibular short implants lost on average 1.22 mm of peri-implant bone at 5 years and patients with 10-mm or longer mandibular implants lost 1.70 mm. Patients with maxillary short implants lost on average 1.25 mm of peri-implant bone at 5 years and patients with 10-mm or longer maxillary implants lost 1.73 mm. Longer implants showed a greater bone loss up to 5 years after loading than short implants both in maxillae (mean difference: -0.48 mm; 95% CI: -0.89 to -0.07 mm; P = 0.024) and in mandibles (mean difference: -0.48 mm; 95% CI: -0.79 to -0.18 mm; P = 0.004). CONCLUSIONS:Five years after loading, 5 × 5 mm implants achieved similar results to longer implants placed in augmented bone. Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster, cheaper and associated with less morbidity; however, 10-year post-loading data are necessary before making reliable recommendations.
    Evaluation of nano-technology-modified zirconia oral implants: a study in rabbits. Lee Jaebum,Sieweke Janet H,Rodriguez Nancy A,Schüpbach Peter,Lindström Håkan,Susin Cristiano,Wikesjö Ulf M E Journal of clinical periodontology OBJECTIVE:The objective of this study was to screen candidate nano-technology-modified, micro-structured zirconia implant surfaces relative to local bone formation and osseointegration. MATERIALS AND METHODS:Proprietary nano-technology surface-modified (calcium phosphate: CaP) micro-structured zirconia implants (A and C), control micro-structured zirconia implants (ZiUnite), and titanium porous oxide implants (TiUnite) were implanted into the femoral condyle in 40 adult male New Zealand White rabbits. Each animal received one implant in each hind leg; thus, 20 animals received A and C implants and 20 animals received ZiUnite and TiUnite implants in contralateral hind legs. Ten animals/group were euthanized at weeks 3 and 6 when biopsies of the implant sites were processed for histometric analysis using digital photomicrographs produced using backscatter scanning electron microscopy. RESULTS:The TiUnite surface demonstrated significantly greater bone-implant contact (BIC) (77.6+/-2.6%) compared with the A (64.6+/-3.6%) and C (62.2+/-3.1%) surfaces at 3 weeks (p<0.05). Numerical differences between ZiUnite (70.5+/-3.1%) and A and C surfaces did not reach statistical significance (p>0.05). Similarly, there were non-significant differences between the TiUnite and the ZiUnite surfaces (p>0.05). At 6 weeks, there were no significant differences in BIC between the TiUnite (67.1+/-4.2%), ZiUnite (69.7+/-5.7%), A (68.6+/-1.9%), and C (64.5+/-4.1%) surfaces (p>0.05). CONCLUSION:TiUnite and ZiUnite implant surfaces exhibit high levels of osseointegration that, in this model, confirm their advanced osteoconductive properties. Addition of CaP nano-technology to the ZiUnite surface does not enhance the already advanced osteoconductivity displayed by the TiUnite and ZiUnite implant surfaces. 10.1111/j.1600-051X.2009.01423.x
    Posterior atrophic jaws rehabilitated with prostheses supported by 5 × 5 mm implants with a nanostructured calcium-incorporated titanium surface or by longer implants in augmented bone. 3-year results from a randomised controlled trial. Gastaldi Giorgio,Felice Pietro,Pistilli Valeria,Barausse Carlo,Ippolito Daniela Rita,Esposito Marco European journal of oral implantology PURPOSE:To evaluate whether 5.0 × 5.0 mm dental implants with a novel nanostructured calcium-incorporated titanium surface could be an alternative to implants of at least 10.0 mm long placed in bone augmented with bone substitutes in posterior atrophic jaws. MATERIALS AND METHODS:Forty patients with atrophic posterior (premolar and molar areas) mandibles with 5.0 mm to 7.0 mm bone height above the mandibular canal, and 40 patients with atrophic maxillas with 4.0 mm to 6.0 mm below the maxillary sinus, were randomised according to a parallel group design to receive between one and three 5.0 mm implants or one to three at least 10.0 mm-long implants in augmented bone at two centres. All implants had a diameter of 5.0 mm. Mandibles were vertically augmented with interpositional bovine bone blocks covered with resorbable barriers. Implants were placed after 4 months. Maxillary sinuses were augmented with particulated porcine bone via a lateral window covered with resorbable barriers, and implants were placed simultaneously. All implants were submerged and loaded after 4 months with provisional prostheses. Four months later, definitive screw-retained or provisionally cement metal-ceramic or zirconia prostheses were delivered. Patients were followed to 3 years post-loading and the outcome measures were: prosthesis and implant failures, any complication, and peri-implant marginal bone level changes. RESULTS:Seven patients dropped out before the 3-year evaluation (two short mandibles, one short maxilla, two augmented mandibles and two augmented maxillae). In mandibles, two grafted patients were not prosthetically rehabilitated because of multiple complications and two implants failed in the same patient (the second was a replacement implant) vs one patient who lost a short implant and crown 2 years after loading. In maxillas one short implant failed with its provisional crown 3 months post-loading. There were no statistically significant differences in prostheses (difference in proportion = 0.001; 95% CI: -0.12 to 0.13; P = 1.000) and implant failures (difference in proportion = 0.00; 95% CI: -0.13 to 0.13; P = 1.000) up to 3 years after loading. Significantly, more complications occurred at mandibular grafted sites: 17 augmented patients were affected by complications vs eight patients treated with short implants in mandibles (difference in proportion = 0.43; 95% CI: 0.13 to 0.64; P = 0.008). In the maxilla, six sinus-lifted patients vs two patients treated with short implants were affected by complications; the difference not being statistically significant (difference in proportion = 0.21; 95% CI: -0.05 to 0.45; P = 0.232). Patients with mandibular short implants lost on average 1.10 mm of peri-implant bone at 3 years and patients with 10.0 mm or longer mandibular implants lost 1.39 mm. Patients with maxillary short implants lost on average 1.04 mm of peri-implant bone at 3 years and patients with 10 mm or longer maxillary implants lost 1.43 mm. Longer implants showed a greater bone loss up to 3 years after loading than short implants both in maxillae (mean difference: -0.39 mm; 95% CI: -0.70 to -0.07 mm; P = 0.017) and in mandibles (mean difference: -0.29 mm; 95% CI: -0.53 to -0.05 mm; P = 0.020). CONCLUSIONS:Three years after loading, 5.0 mm × 5.0 mm implants achieved similar results than longer implants placed in augmented bone. Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster, cheaper and associated with less morbidity. However, 5- to 10-year post-loading data are necessary before making reliable recommendations.
    Effectivity of air-abrasive powder based on glycine and tricalcium phosphate in removal of initial biofilm on titanium and zirconium oxide surfaces in an ex vivo model. John Gordon,Becker Jürgen,Schwarz Frank Clinical oral investigations OBJECTIVES:The purpose of the present study was the evaluation of effectiveness and efficiency of a powder consisting of glycine and tricalcium phosphate in comparison to two established powders based on glycine or sodium bicarbonate in biofilm removal on titanium and zirconium implant surfaces. MATERIALS AND METHODS:Biofilm was collected for 48 h by five volunteers. A total of 69 titanium and 69 zirconium samples were randomly assigned to test and control groups. Residual plaque areas (RPA) and treatment time were taken as parameters. RESULTS:Within the titanium groups, mean RPA was determined in the following descending order: sodium bicarbonate > glycine > glycine + tricalcium phosphate. Differences between the groups were significant, p < 0.05. Mean treatment time in the titanium groups was determined in the following descending order without significant differences, p > 0.05: glycine + tricalcium phosphate > sodium bicarbonate > glycine. Regarding the zirconium groups, mean RPA was detected in the following descending order, without significant differences, p > 0.05: glycine > sodium bicarbonate > glycine + tricalcium phosphate. Mean treatment time of the glycine + tricalcium phosphate group was significantly lower than in the control groups, p < 0.05. CONCLUSIONS:It can be concluded that glycine + tricalcium phosphate seemed to be more effective than the control groups for biofilm removal on titanium and zirconium implant surfaces. Especially on zirconium surfaces, decontamination with glycine + tricalcium phosphate seemed to be more efficient than treatment with glycine or sodium bicarbonate. CLINICAL RELEVANCE:The combination of glycine and tricalcium phosphate could improve the clinical outcomes of air-abrasive device in nonsurgical peri-implantitis therapy. 10.1007/s00784-015-1571-8
    Inlay-retained zirconia fixed dental prosthesis: clinical and laboratory procedures. Monaco Carlo,Cardelli Paolo,Bolognesi Michele,Scotti Roberto,Ozcan Mutlu The European journal of esthetic dentistry : official journal of the European Academy of Esthetic Dentistry Many treatment options are currently available for single tooth replacement, such as metal-ceramic, all-ceramic, direct or indirect fiber-reinforced composite fixed dental prostheses (FDPs) or implants. Inlay-retained FDPs could be indicated especially when adjacent teeth have preexisting restorations and where implant placement is not possible or not indicated. In such cases, indication of both metal-ceramic and fiber-reinforced composite FDPs has certain disadvantages. This paper describes the use of all-ceramic inlay-retained FDPs with zirconia frameworks, veneered with a press-on technique. The retainer margins were made of pressed ceramic to make adhesive luting possible. In deep cavities, a full contour press-on ceramic all around the retainers increased the available surface area for the adhesive approach.
    Bacterial adhesion and colonization differences between zirconium oxide and titanium alloys: an in vivo human study. Salihoglu Umut,Boynuegri Duygu,Engin Doruk,Duman Ayse Nurcan,Gokalp Pelin,Balos Koksal The International journal of oral & maxillofacial implants PURPOSE:The purpose of this study was to compare zirconium oxide and titanium alloys with respect to their tendency to adhesion and colonization of two periodontal pathogens on both hard surfaces and on soft tissues in vivo. MATERIALS AND METHODS:The present study was designed as a prospective stratified randomized controlled clinical trial. Patients were scheduled to receive two implants with different types of abutments in the posterior mandible. Three months after implant placement, titanium and zirconium abutments were connected. Five weeks after abutment connections, the abutments were removed, probing depth measurements were recorded, and gingival biopsy samples were obtained. Abutments and biopsy specimens were analyzed by reverse-transcriptase polymerase chain reaction to compare the DNA copy numbers of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and total bacteria. The surface free energy of the abutments was calculated by sesile water drop before replacement. RESULTS:No statistically significant differences were found between probing depths or DNA copy numbers of A actinomycetemcomitans, P gingivalis, and total bacteria both for both titanium alloys and zirconium oxide surfaces and the biops specimens obtained from their buccal gingival. With respect to the surface free energy of zirconium and titanium abutments, zirconium abutments showed lower surface free energy than titanium abutments. CONCLUSION:The results of this study showed that zirconium oxide surfaces have comparable properties to titanium alloy surfaces in their tendency to adhesion and colonization of two periodontal pathogens on both hard surfaces and in soft tissues.
    Bioactivity of NANOZR Induced by Alkali Treatment. Nishizaki Mariko,Komasa Satoshi,Taguchi Yoichiro,Nishizaki Hiroshi,Okazaki Joji International journal of molecular sciences In recent years, zirconia has been a recognized implant material in clinical dentistry. In the present study, we investigated the performance of an alkali-modified ceria-stabilized tetragonal ZrO₂ polycrystalline ceramic-based nanostructured zirconia/alumina composite (NANOZR) implant by assessing surface morphology and composition, wettability, bovine serum albumin adsorption rate, rat bone marrow (RBM) cell attachment, and capacity for inducing bone differentiation. NANOZR surfaces without and with alkali treatment served as the control and test groups, respectively. RBM cells were seeded in a microplate with the implant and cultured in osteogenic differentiation medium, and their differentiation was evaluated by measuring alkaline phosphatase (ALP) activity, osteocalcin (OCN) production, calcium deposition, and osteogenic gene expression. The alkali-treated NANOZR surface increased ALP activity, OCN production, calcium deposition, and osteogenesis-related gene expression in attached RBM cells. These data suggest that alkali treatment enhances the osteogenesis-inducing capacity of NANOZR implants and may therefore improve their biointegration into alveolar bone. 10.3390/ijms18040780
    In vitro adherence of periodontopathic bacteria to zirconia and titanium surfaces. Egawa Masahiro,Miura Tadashi,Kato Tetsuo,Saito Atsushi,Yoshinari Masao Dental materials journal Tetragonal zirconia polycrystals (TZP) has drawn attention as a potential alternative to titanium (Ti) in dental implant treatment, as it minimizes both allergic reactions and esthetic problems. It is also important for dental implants to maintain plaque-free surfaces to prevent peri-implantitis. The purpose of this study was to investigate in vitro adherence of periodontopathic bacteria to TZP comparing with Ti.Periodontopathic bacteria were cultured on polished discs of two kinds of TZP, and Ti as a control. After incubation, the numbers of adherent bacteria were estimated. No significant differences among specimens were observed in the initial attachment, although a decrease was observed in initial attachment to saliva-coated specimens. In the bacterial colonization, no significant differences were recognized among specimens. The adherence of the periodontopathic bacteria on TZP was similar to that on Ti. These results suggest that a strategy is required for inhibition of the bacterial adherence to TZP.
    Ovoid zirconia implants: anatomic design for premolar replacement. Oliva Josep,Oliva Xavi,Oliva Josep D The International journal of periodontics & restorative dentistry Traditionally, missing and hopeless teeth have been replaced by threaded cylindric implants. Implant manufacturers have tried to design implants that more closely resemble tooth anatomy, but the neck and abutment connection areas have not changed much in the past 30 years. Some companies have produced titanium implants with scalloped contours, but the clinical application of this remains uncertain. The combination of anatomically oriented implant designs, newer biomaterials such as zirconia ceramics, and modified surfaces has resulted in dental implants that can be specially designed for the replacement of individual teeth in both arches. Ovoid zirconia implants have been specially developed and produced to replace missing or hopeless premolars. This article discusses the treatment of a patient with an ovoid zirconia implant (CeraRoot Type 14) to replace a premolar.
    Immediate, non-submerged, root-analogue zirconia implants placed into single-rooted extraction sockets: 2-year follow-up of a clinical study. Pirker W,Kocher A International journal of oral and maxillofacial surgery This study evaluated non-submerged, root-analogue zirconia implants with two different surfaces for immediate single-rooted tooth replacement in 18 patients. After tooth extraction the root was laser scanned and one-piece root analogue zirconia dental implants with one of two different surfaces were manufactured. In group A (n=6) the implant surface was roughened by sandblasting only, in group B (n=12) additional macroretentions limited to the interdental space, to avoid fracture of the thin buccal cortex, were designed prior to laser scanning. Implants were placed in the socket 1-8 days after extraction by tapping and restored with a composite crown 3-5 months later. Implant survival, level of marginal bone and adverse soft tissue changes were recorded. No complications occurred during the healing period. In group A, all implants were lost within 2 months, with an unaltered extraction socket. In group B, overall survival rate was 92% for implants that were functional for 1-33 months. Excellent aesthetic and functional results were achieved with the composite crown with minimal bone resorption and soft tissue recession. Significant modifications, such as macroretentions seem to indicate that primary stability and excellent osseointegration of immediate root-analogue zirconia implants can be achieved, while preventing unaesthetic bone resorption. 10.1016/j.ijom.2009.07.008
    Zirconia for teeth and implants: a case series. Kollar Andrea,Huber Sandra,Mericske Ernö,Mericske-Stern Regina The International journal of periodontics & restorative dentistry This case series reports on the use of nonsilica-based high-strength full ceramics for different prosthetic indications. Fifty-two consecutive patients received tooth- or implant-supported zirconia reconstructions during a 2-year period. The observation period for reexamination was 12 to 30 months. The most frequent indications were single crowns and short-span fixed partial dentures. A few implant superstructures were screw-retained, whereas all remaining restorations were cemented on natural teeth or zirconia implant abutments. Clinical examination included biologic (probing depths, bleeding on probing) and esthetic (Papilla Index) parameters, as well as technical complications. No implant was lost or caused any problems, but two teeth were lost after horizontal fracture. Overall, the periodontal parameters were favorable. Fractures of frameworks or implant abutments were not observed. Abutment-screw loosening occurred once for one premolar single crown. Furthermore, five implant crowns in the posterior region exhibited chipping of the porcelain veneering material. With regard to esthetics, no reconstructions were considered unacceptable, but three crowns were remade shortly after delivery. In this short-term study, it was observed that biologic, esthetic, and mechanical properties of zirconia were favorable, and the material could be used in various prosthetic indications on teeth or implants.
    Mechanical, biological and clinical aspects of zirconia implants. Van Dooren Eric,Calamita Marcelo,Calgaro Murilo,Coachman Christian,Ferencz Jonathan L,Pinho Claudio,Silva Nelson R The European journal of esthetic dentistry : official journal of the European Academy of Esthetic Dentistry The objective of this narrative overview is to discuss several in vitro and in vivo studies regarding the performance of one-piece zirconia implants in combination with the description of two clinical scenarios where zirconia implant prototypes were utilized with emphasis on the possible scientific and clinical concerns that may affect the functional, biological and esthetic long-term outcomes.
    Effect of Bonding and Rebonding on the Shear Bond Strength of Two-Piece Implant Restorations. Putra Armand,Chung Kwok-Hung,Guilherme Nuno Marques,Cagna David R Journal of prosthodontics : official journal of the American College of Prosthodontists PURPOSE:To evaluate the rebonding strength of ceramics to titanium alloy after disassembling by heat treatment. MATERIALS AND METHODS:A total of 40 titanium alloy (titanium-6 aluminum-4 vanadium) disks (4.0 × 6.6 mm) and 20 zirconia (Lava Plus) disks were manufactured using computer-aided design and computer-aided manufacturing (CAD/CAM) technology. Twenty heat-pressed lithium disilicate glass-ceramic (IPS e.max Press LT) disks were fabricated and used as controls. Bonding protocol for each specimen surface was performed according to manufacturer's instructions. Specimens (n = 10) of zirconia/titanium alloy (ZR) and lithium disilicate/titanium alloy (LD) were bonded using adhesive resin cement (RelyX Ultimate) and then subjected to a heat treatment (HT, 320°C, 2 minutes) to disassemble the bonding complex, cleaned with aluminum oxide airborne-particle abrasion, and rebonded following the initial protocol, group ZRHT and group LDHT, respectively. After 5000 cycles of thermal cycling, a shear bond test was conducted. A universal testing machine was used at a 5 mm/min crosshead speed. Failed specimens were examined with stereomicroscopy at 10× magnification to identify the mode of failure. One-way ANOVA and Tukey HSD tests were applied for statistical analysis of the shear bond strength data, with statistical significance at α = 0.05. RESULTS:The mean ± SD bond strength values ranged from 28.3 ± 7.2 to 45.9 ± 9.7 MPa. Statistically significant lower shear bond strength values were obtained from the LD group (p = 0.002, F = 5.89), while no statistically significant differences in bond strength were observed between the ZR and ZRHT groups (p > 0.05). Failure mode was predominantly mixed-type failure pattern for all specimens. CONCLUSIONS:Heat and abrasion surface treatment increased the bond strength of lithium disilicate glass-ceramics cemented to titanium alloy, but no effect was observed on zirconia/titanium alloy bonding. 10.1111/jopr.13024
    Ten-Year Follow-Up of Implant-Supported All-Ceramic Fixed Dental Prostheses: A Randomized, Prospective Clinical Trial. Larsson Christel,Vult von Steyern Per The International journal of prosthodontics PURPOSE:The aim of this study was to evaluate the long-term clinical performance of and patient satisfaction with implant-supported all-ceramic fixed dental prostheses (FDPs) and to compare two different all-ceramic systems, Denzir (DZ) and In-Ceram Zirconia (InZ). MATERIALS AND METHODS:A total of 18 patients received 25 partial FDPs; 13 DZ, and 12 InZ. RESULTS:Of these patients, 17 attended the 10-year follow-up. None of the restorations had fractured. Fractures of the veneering porcelain were observed in nine patients; two from the InZ group and seven from the DZ group. All FDPs were in use, and all patients were fully satisfied with the treatment. CONCLUSION:Results from this long-term follow-up suggest that implant-supported all-ceramic FDPs are an acceptable treatment alternative. 10.11607/ijp.4328
    A prospective study of implant-supported full-arch yttria-stabilized tetragonal zirconia polycrystal mandibular fixed dental prostheses: three-year results. Larsson Christel,Vult von Steyern Per,Nilner Krister The International journal of prosthodontics PURPOSE:The development of high-strength oxide ceramic materials has led to increased interest in all-ceramic fixed dental prostheses (FDPs). Success rates reported in clinical studies for all-ceramic FDPs based on high-strength oxide ceramic materials reportedly approach those of porcelain-fused-to-metal FDPs. These reconstructions, however, are still of limited size and have mainly concerned FDPs supported by natural teeth. The purpose of this study was to evaluate the clinical performance of multiunit all-ceramic FDPs supported by dental implants. MATERIALS AND METHODS:Ten patients received mandibular yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) FDPs manufactured according to the Cercon technique and supported by four Astra Tech implants. Nine patients received 10-unit FDPs and one patient received a 9-unit FDP. The FDPs were cemented with Panavia F 2.0 onto individually prepared titanium abutments. The FDPs were evaluated at baseline and after 12, 24, and 36 months. RESULTS:At the 3-year follow-up, all FDPs were in use, and all patients were fully satisfied with their treatment. None of the reconstructions had fractured. Superficial chip-off fractures of the veneering porcelain were, however, observed in nine patients (34 of 99 units, 34%). CONCLUSION:Results from this 3-year study suggest that implant-supported full-arch Y-TZP FDPs manufactured according to the Cercon technique should be viewed as a treatment alternative cautiously. A better understanding of the factors resulting in chip-off fractures is needed, together with longer follow-up studies involving larger numbers of patients, before the material and technique can be recommended for general use.
    Enhanced osteoblast function on ultraviolet light-treated zirconia. Att Wael,Takeuchi Masato,Suzuki Takeo,Kubo Katsutoshi,Anpo Masakazu,Ogawa Takahiro Biomaterials Unlike titanium, surface roughening of zirconia for enhanced bone integration has been technically challenging. The photochemical reaction of semiconductor oxides, e.g., titanium dioxide, has earned considerable and broad interest in environmental and clean energy sciences. This study determined whether ultraviolet (UV) light treatment of zirconia enhances its bioactivity on osteoblasts. Machined zirconia disks were treated with UV light for various time periods up to 48 h. UV light treatment for 48 h increased the rates of attachment, spread, and proliferation of rat bone marrow-derived osteoblasts. Alkaline phosphatase-positive and mineralized nodule areas doubled on UV light-treated zirconia. The expression of osteoblastic genes, such as osteopontin and osteocalcin, was not modulated by UV light treatment. X-ray diffraction and X-ray photoelectron spectroscopy analyses showed that zirconia disks consisted of monoclinic and tetragonal phases of ZrO(2) and Y(2)O(3) having a wide light absorption band of 200-400 nm with its peak at <250 nm. UV light treatment transformed the zirconia surface from hydrophobic to hydrophilic status and reduced the atomic percentage of surface carbon in a UV light dose-dependent manner. These results suggest that UV treatment of yttrium-containing partially stabilized zirconia enhances its bioactivity on osteoblasts, in terms of their attachment, proliferation, and eventually mineralization. This biofunctionalization was associated with UV light-catalytic hydrophilic conversion of zirconia surfaces and progressive removal of hydrocarbons. 10.1016/j.biomaterials.2008.11.024
    Five-year success rate of 831 consecutively placed Zirconia dental implants in humans: a comparison of three different rough surfaces. Oliva Josep,Oliva Xavi,Oliva Josep D The International journal of oral & maxillofacial implants PURPOSE:The aim of this study was to evaluate the 5-year success rate of zirconia (ZrO2) implants with three different kinds of surfaces. MATERIALS AND METHODS:One-piece zirconia dental implants (CeraRoot) with three different roughened surfaces were designed and manufactured for this study: coated, uncoated, and acid-etched. Five different implant designs were manufactured. Standard or flapless surgical procedures were used for implant placement. Simultaneous bone augmentation or sinus elevation was performed when bone height or width was insufficient. Definitive all-ceramic restorations were placed 4 months after implant placement (8 months or more for implants when bone augmentation or sinus elevation was performed). The implants were followed up to 5 years (mean, 3.40 +/- 0.21). RESULTS:In all, 831 implants were placed in 378 patients with a mean age of 48 years. The overall implant success rate after 5 years of follow-up was 95% (92.77% for uncoated implants, 93.57% for coated implants, and 97.60% for acid-etched implants). The success rate of the acid-etched surface group was significantly better than that of the other two. CONCLUSION:From this midterm investigation, it can be concluded that zirconia dental implants with roughened surfaces might be a viable alternative for tooth replacement. Further follow-up is needed to evaluate the long-term success rates of the implant surfaces studied.
    Inflammatory response to implantation of transparent nanocrystalline yttria-stabilized zirconia using a dorsal window chamber model. Damestani Yasaman,Galan-Hoffman Diego E,Ortiz Daniel,Cabrales Pedro,Aguilar Guillermo Nanomedicine : nanotechnology, biology, and medicine The long-range goal of the windows to the brain (WttB) is to improve patient care by providing a technique for delivery and/or collection of light into/from the brain, on demand, over large areas, and on a chronically-recurring basis without the need for repeated craniotomies. To evaluate the potential of nanocrystalline yttria-stabilized-zirconia (nc-YSZ) cranial implant for optical therapy and imaging, in vivo biocompatibility was studied using the dorsal window chamber model in comparison with control (no implant) and commercially available cranial implant materials (PEEK and PEKK). The host tissue response to implant was characterized by using transillumination and fluorescent microscopy to measure leukocyte adhesion, blood vessel diameter, blood flow rate, and vascular permeability over two weeks. The results indicated the lack of inflammatory reaction of the host tissue to nc-YSZ at the microscopic level, suggesting that nc-YSZ is a good alternative material for cranial implants. 10.1016/j.nano.2016.04.009
    A randomized, prospective, open-ended clinical trial of zirconia fixed partial dentures on teeth and implants: interim results. Sagirkaya Elcin,Arikan Serdar,Sadik Burak,Kara Cankat,Karasoy Durdu,Cehreli Murat The International journal of prosthodontics PURPOSE:The aim of this randomized controlled clinical trial was to compare the outcomes of zirconia crowns and fixed partial dentures (FPDs) supported by teeth or implants. MATERIALS AND METHODS:Patients were recruited based on inclusion/exclusion criteria, and 59 eligible subjects were assigned randomly to treatment by one of four zirconia systems (Cercon, ZirkonZahn, Lava, and Katana). One hundred seven single-tooth and 160 three- to six-unit FPDs were fabricated on teeth and implants and cemented using composite resin cement. Californian Dental Association (CDA) quality evaluation, Plaque Index, and Gingival Index scores were recorded, and radiographic assessment of the restorations was performed using periapical and panoramic radiographs at baseline and annually up to 4 years. RESULTS:Five failures (1.9%) were recorded. The 4-year Kaplan-Meier survival probabilities of FPDs were higher than those of single-tooth restorations (P = .046). The highest survival probability for crowns was observed for Katana and the lowest for Cercon (P < .05). For FPDs, the survival probabilities of Lava restorations were similar to those of Cercon but lower than those of ZirkonZahn and Katana (P < .05). The 4-year survival probabilities of implant- and tooth-supported crowns were comparable (P = .182). Regarding CDA ratings, the slight marginal discrepancy scores for the Cercon restorations were higher than for the other systems at 1 year (P < .05). In FPDs, 94.5% of Katana FPDs had slight or gross color mismatch scores, and the difference between color and surface ratings among zirconia systems was significant (P < .05). FPDs had better periodontal scores than crowns over the 4-year observation period (P < .05). CONCLUSION:The 4-year interim results of this study suggest that zirconia systems used to fabricate FPDs have predictably high survival rates on teeth and implants and may exhibit differences, particularly in terms of mechanical failures, marginal adaptation, and color matching.
    Effect of Er:YAG, CO(2) and diode laser irradiation on surface properties of zirconia endosseous dental implants. Stübinger Stefan,Homann Frank,Etter Christof,Miskiewicz Miroslaw,Wieland Marco,Sader Robert Lasers in surgery and medicine BACKGROUND AND OBJECTIVES:Zirconia implants (ZI) are becoming more popular in implant dentistry, as a result of their favorable esthetic outcome. However, little is known about the impact laser application has on this material in the course of peri-implantitis treatment. The objective of this investigation was to analyze the influence of Er:YAG, CO(2) and diode laser irradiation on polished ZI. MATERIAL AND METHODS:Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic disks were irradiated at different power settings with either an Er:YAG, CO(2) or diode laser. The surface of the disks was analyzed by scanning electron microscopy (SEM) and confocal 3D white light microscopy (CWLM). In addition energy-dispersive X-ray (EDX) analysis was performed on all disks. Six specimens were used for each parameter set of each laser. RESULTS:SEM analysis demonstrated that, regardless of the power settings, neither the diode laser nor the Er:YAG laser caused any visible surface alterations to ZI. The results of the CWLM were in agreement with the SEM pictures. However, Er:YAG irradiation did penetrate through the disks. At various power settings, the CO(2) treatment was characterized by material cracking and melting. The increased roughness values (from CWLM) of the ZI underlined the SEM observations. CONCLUSION:In contrast to diode and Er:YAG laser irradiation, the CO(2) laser revealed distinct surface alterations to zirconia at various laser parameters. However, the Er:YAG laser cannot be recommended for the treatment of ailing implants, as the laser beam penetrates the material. In this respect, currently, diode lasers seem to be the only laser systems offering surface preservation and safety in the treatment of peri-implantits with ZI. 10.1002/lsm.20614
    Histological behaviour of zirconia implants: an experiment in rats. Mai Ronald,Kunert-Keil Christiane,Grafe Anna,Gedrange Tomasz,Lauer Günter,Dominiak Marzena,Gredes Tomasz Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft New biomaterials including surface modifications should undergo in vitro and in vivo evaluation before clinical trials. The objective of our in vivo study was to evaluate the biocompatibility of one of the newly fabricated zirconia implant surfaces, called "mds". For this purpose, the osseointegration of these implants was analyzed after implantation in surgically created defects in the cranium of adult male rats. After a healing period of 28 and 56 days, respectively, bone tissue specimens containing the implants were processed and histologically analyzed. For this purpose, sections were stained with haematoxylin/eosin and Masson Goldner trichrome. No signs of cellular inflammatory infiltrate were found in any of the animals. After 28 days, slices showed pronounced development of blood vessels and bone regeneration. After 56 days of healing, direct bridging of the bone defects was detectable with distinctly visible kit lines. There were cell rich areas of connective tissue/bone marrow between zirconia discs and bearing bone. Histomorphometric analysis presented a regenerated bone mean value of 36.3% after 28 days of healing. After 56 days of healing, a 1.6 fold increased bone mean value was observed (58.2%). Using the same analysis, 1% and 39.9% of bone-implant-contact was visible after both healing periods, respectively. On average, connective tissue/marrow spaces occupied 99% of implant-contact-area after 28 days of healing. This area was reduced to 60.1% after 56 days. Within the limits of the animal investigation presented, it was concluded that the tested surface modification of zirconia implants were biocompatible and osseoconductive. 10.1016/j.aanat.2012.09.004
    Osseointegration of zirconia and titanium implants in a rabbit tibiae model evaluated by microtomography, histomorphometry and fluorochrome labeling analyses. Martins R,Cestari T M,Arantes R V N,Santos P S,Taga R,Carbonari M J,Oliveira R C Journal of periodontal research OBJECTIVES:This study compares the osseointegration of machined-zirconia implants containing yttria (M-Y-TZP) with machined (M-Ti) and resorbable blast media (RBM-Ti) titanium implants. MATERIAL AND METHODS:M-Y-TZP, M-Ti and RBM-Ti implants were randomly placed in rabbit tibiae. Fluorochrome bone labels (tetracycline, alizarin and calcein) were administered at different time periods. After 8 weeks, osseointegration was evaluated in terms of bone-to-implant contact (BIC), new bone area (nBA), remaining cortical bone area (rBA) and temporal quantification of fluorochromes, using micro-CT and histomorphometric analyses. RESULTS:RBM-Ti implants showed higher resorption of the remaining cortical bone and bone formation (rBA = 36.9% and nBA = 38.8%) than M-Y-TZP implants (rBA = 48% and nBA = 26.5%). The BIC values showed no differences among the groups in the cortical region (mean = 52.2%) but in the medullary region, they were 0.45-fold higher in the RBM-Ti group (51.2%) than in the M-Y-TZP group (35.2%). In all groups, high incorporation of tetracycline was observed (2nd to 4th weeks), followed by alizarin (4th to 6th weeks) and calcein (6th to 8th weeks). In the cortical region, incorporation of tetracycline was similar between RBM-Ti (49.8%) and M-Y-TZP (35.9%) implants, but higher than M-Ti (28.2%) implants. Subsequently, alizarin and calcein were 1.1-fold higher in RBM-Ti implants than in the other implants. In the medullary region, no significant differences were observed for all fluorochromes. CONCLUSION:All implants favored bone formation and consequently promoted primary stability. Bone formation around the threads was faster in RBM-Ti and M-Y-TZP implants than in M-Ti implants, but limited bone remodeling with M-Y-TZP implants over time can have significant effects on secondary stability, suggesting caution for its use as an alternative substitute for titanium implants. 10.1111/jre.12508
    Plasma of Argon Increases Cell Attachment and Bacterial Decontamination on Different Implant Surfaces. Canullo Luigi,Genova Tullio,Wang Hom-Lay,Carossa Stefano,Mussano Federico The International journal of oral & maxillofacial implants PURPOSE:This in vitro study tested the effects of argon atmospheric pressure dielectric barrier discharge (APDBD) on different implant surfaces with regard to physical changes, bacterial decontamination, and osteoblast adhesion. MATERIALS AND METHODS:Seven hundred twenty disks with three different surface topographies-machined (MAC), titanium plasma-sprayed (TPS), and zirconia-blasted and acid-etched (ZRT)-were tested in this experiment. Bacterial adhesion tests were performed repeatedly on a simplified biofilm of Streptococcus mitis. Bacteria were incubated in the presence of the samples, which were subsequently either left untreated as controls or treated with APDBD for 30, 60, and 120 seconds. Samples were then metalized, prior to the recurring acquisition of images using a scanning electronic microscope (SEM). Protein adsorption, surface wettability, and early biologic response were determined for both treated (120 seconds) and untreated implant surfaces. For depicting the eukaryotic cell behavior, preosteoblastic murine cells were used. Cells were conveniently stained, and nuclei were counted. Cell viability was assessed by a chemiluminescent assay at 1, 2, and 3 days. RESULTS:On all treated samples, values of the contact angle measurements were lower than 10 degrees. The untreated samples showed values of contact angle of 80, 100, and 110 degrees, respectively, for MAC, TPS, and ZRT. The protein adsorption on TPS and ZRT was significantly increased after the plasma of argon treatment. However, no significant effect was noted on the MAC disks. The number and the cell spreading area of adherent osteoblasts significantly increased in all treated surfaces. Nonetheless, argon treatment did not influence the osteoblast proliferation and viability at different time points. Bacteria adhesion was significantly reduced, even after 60 seconds of argon treatment. CONCLUSION:Preliminary data showed that argon atmospheric pressure dielectric barrier discharge disinfected the implant surface, with potential to promote osteoblast attachment and spreading, suggesting this may be a possible approach to clean a peri-implantitis-contaminated implant surface. 10.11607/jomi.5777
    In vivo performance of zirconia and titanium implants: a histomorphometric study in mini pig maxillae. Gahlert M,Roehling S,Sprecher C M,Kniha H,Milz S,Bormann K Clinical oral implants research OBJECTIVES:To compare the bone tissue response to surface-modified zirconia (ZrO2 ) and titanium implants. METHODS:Cylindrical low-pressure injection moulded zirconia (ZrO2 ) implants were produced with an acid-etched surface. Titanium implants with identical shape, sandblasted and acid-etched surface (SLA) served as controls. Eighteen adult miniature pigs received both implant types in the maxilla 6 months after extraction of the canines and incisors. The animals were euthanized after 4, 8 and 12 weeks and 16 zirconia and 18 titanium implants with the surrounding tissue were retrieved, embedded in methylmethacrylate and stained with Giemsa-Eosin. The stained sections were digitized and histomorphometrically analysed with regard to peri-implant bone density (bone volume/total volume) and bone-implant contact (BIC) ratio. Statistical analysis was performed using Mann-Whitney' U-test. RESULTS:Histomorphometrical analysis showed direct osseous integration for both materials. ZrO2 implants revealed mean peri-implant bone density values of 60.4% (SD ± 9.9) at 4 weeks, 65.4% (SD ± 13.8) at 8 weeks, and 63.3% (SD ± 21.5) at 12 weeks after implantation, whereas Ti-SLA implants demonstrated mean values of 61.1% (SD ± 6.2), 63.6% (SD ± 6.8) and 68.2% (SD ± 5.8) at corresponding time intervals. Concerning the BIC ratio, the mean values for ZrO(2) ranged between 67.1% (SD ± 21.1) and 70% (SD ± 14.5) and for Ti-SLA between 64.7% (SD ± 9.4) and 83.7% (SD ± 10.3). For the two parameters investigated, no significant differences between both types of implants could be detected at any time point. CONCLUSION:The results indicate that there was no difference in osseointegration between ZrO2 implants and Ti-SLA controls regarding peri-implant bone density and BIC ratio. 10.1111/j.1600-0501.2011.02157.x
    Soft and Hard Tissue Response to Zirconia versus Titanium One-Piece Implants Placed in Alveolar and Palatal Sites: A Randomized Control Trial. Siddiqi Allauddin,Kieser Jules August,De Silva Rohana Kumara,Thomson William Murray,Duncan Warwick John Clinical implant dentistry and related research BACKGROUND:Titanium (Ti) implants have been used in the last four decades to replace missing teeth. Alternatives to Ti such as zirconia (Zr) may offer aesthetic advantages and be more acceptable to patients and clinicians concerned about Ti allergy but must show equivalent biological acceptability to Ti. PURPOSE:The research aimed to investigate soft and hard tissue response to Ti and Zr implants in edentulous patients. MATERIALS AND METHODS:The research included 24 participants (Ti = 12, Zr = 12) restored with one-piece ball-abutment implants to support overdentures. Participants received four maxillary implants (two in the premolar alveolus, one off center in the alveolar midline, and one wide-diameter implant in the anterior median palate) and three mandibular implants (one in the midline and bilateral posterior implants). RESULTS:Success rates for both Ti and Zr implants were low, 67.9% for all alveolar implants and a survival rate of 50.0% for the palatal implants. Only 11 (52.4%) of 21 palatal implants survived the follow-up period. Peri-implant health was equivalent for Ti and Zr implants and showed no statistically significant changes from loading to the 1-year follow-up. Statistically significant differences were noted in radiographic bone level between Ti and Zr implants (p = .02), with Zr showing greater bone loss. CONCLUSIONS:Although the failure rates with the one-piece Zr implants were higher than with the Ti ones, suggesting that the former's clinical usage as in this study cannot be recommended, it should be borne in mind that the fault may also lie with the novel prosthodontic design which was used. 10.1111/cid.12159
    Comparison of clinical performance of zirconia implants and titanium implants in animal models: a systematic review. Manzano Guillermo,Herrero L Rubén,Montero Javier The International journal of oral & maxillofacial implants PURPOSE:This study aimed to compare the values of removal torque (RT) and bone-implant contact (BIC) reported in different animal studies for zirconia and titanium implants. MATERIALS AND METHODS:A systematic review of the literature was performed to analyze BIC and RT of animal studies in which both zirconia and titanium dental implants were used. To identify the studies to include in this systematic review, an exhaustive search of PubMed was performed of animal studies published in English with reports on the quantification of the osseointegration of both titanium and zirconia implants by means of BIC and/or RT. The results were aggregated and analyzed within each of the animal models (pig, rabbit, rat, monkey, dog, and sheep). RESULTS:The selection process resulted in a final sample of 16 studies. In general, no significant differences were found between titanium and zirconia. The significant differences in terms of BIC and RT reported by the authors were attributable to the different surface treatments and microporosities of the implant surfaces studied, not to the materials themselves. Only two articles reported significantly lower BIC for modified zirconia implants as compared to modified titanium implants. Four authors described statistically significant differences in terms of RT between zirconia and titanium implants in the different animal models, regardless of the surface treatment received by the implants. CONCLUSIONS:Within the limitations of this study, the values for the BIC and RT of zirconia implants in most of the studies analyzed did not show statistical differences compared with titanium implants. Modified-surface zirconia may have potential as a candidate for a successful implant material, although further clinical studies are necessary. 10.11607/jomi.2817
    Enhanced Cell Response to Zirconia Surface Immobilized with Type I Collagen. Hsu C M,Sun Y S,Huang H H Journal of dental research Zirconia (ZrO) dental implants provide good biocompatibility, have good corrosion resistance, and have a color that is similar to that of natural teeth. Unfortunately, ZrO is a bioinert material and therefore achieves osseointegration difficultly. In this study, we sought to enhance osseointegration by producing rough ZrO surfaces that contain hydroxyl groups (designated ZSA) through the use of sandblasting in conjunction with alkaline treatment. We immobilized type I collagen on ZSA surfaces using the natural cross-linker, procyanidin. Our results further showed that surfaces produced in ZSA-P/C featured more and steadier type I collagen than surfaces produced in ZSA-C. The ZSA-P/C also presented superior cell responses in terms of adhesion, proliferation, and mineralization of human bone marrow mesenchymal stem cells. The enhanced cell responses in the ZSA-P/C were induced through the prolonged activation of focal adhesion kinase, AKT (the phosphoinositide 3-kinase pathway), and p38 (the mitogen-activated protein kinase pathway). The simple and novel approach to immobilize type I collagen on roughened ZrO surfaces presented in this article can likely benefit dental implant applications. 10.1177/0022034519828702
    Survival of anterior cantilevered all-ceramic resin-bonded fixed dental prostheses made from zirconia ceramic. Sasse Martin,Kern Matthias Journal of dentistry OBJECTIVES:This study evaluated the clinical outcome of all-ceramic resin-bonded fixed dental prostheses (RBFDPs) with a cantilevered single-retainer design made from zirconia ceramic. METHODS:Forty-two anterior RBFDPs with a cantilevered single-retainer design were made from yttrium oxide-stabilized zirconium oxide ceramic. RBFDPs were inserted using Panavia 21 TC as luting agent after air-abrasion of the ceramic bonding surface. RESULTS:During a mean observation time of 61.8 months two debondings occurred. Both RBFDPs were rebonded using Panavia 21 TC and are still in function. A caries lesion was detected at one abutment tooth during recall and was treated with a composite filling. Therefore, the overall six-year failure-free rate according to Kaplan-Meier was 91.1%. If only debonding was defined as failure the survival rate increased to 95.2%. Since all RBFDPs are still in function the overall survival rate was 100% after six years. CONCLUSIONS:Cantilevered zirconia ceramic RBFDPs showed promising results within the observation period. CLINICAL SIGNIFICANCE:Single-retainer resin-bonded fixed dental prostheses made from zirconia ceramic show very good mid-term clinical survival rates. They should therefore be considered as a viable treatment alternative for the replacement of single missing anterior teeth especially as compared to an implant therapy. 10.1016/j.jdent.2014.02.021
    Mechanical properties of bone tissues surrounding dental implant systems with different treatments and healing periods. Kim Do-Gyoon,Kwon Hyun-Jung,Jeong Yong-Hoon,Kosel Erin,Lee Damian J,Han Jung-Suk,Kim Hye-Lee,Kim Dae-Joon Clinical oral investigations OBJECTIVES:The objective of the current study was to examine whether the nanoindentation parameters can assess the alteration of bone quality resulting from different degrees of bone remodeling between bone tissue ages around the dental implant interface with different treatments and healing periods. MATERIALS AND METHODS:Dental implants were placed in mandibles of six male dogs. Treatment groups included: resorbable blast media-treated titanium (Ti) implants, alumina-blasted zirconia implants (ATZ), alumina-blasted zirconia implants applied with demineralized bone matrix (ATZ-D), and alumina-blasted zirconia implants applied with rhBMP-2 (ATZ-B). Nanoindentation modulus (E), hardness (H), viscosity (η), and viscoelastic creep (Creep/P ) were measured for new and old bone tissues adjacent to the implants at 3 and 6 weeks of post-implantation. A total of 945 indentations were conducted for 32 implant systems. RESULTS:Significantly lower E, H, and η but higher Creep/P were measured for new bone tissues than old bone tissues, independent of treatments at both healing periods (p < 0.001). All nanoindentation parameters were not significantly different between healing periods (p > 0.568). ATZ-D and ATZ-B implants had the stiffer slope of correlation between E and Creep/P of the new bone tissue than Ti implant (p < 0.039). CONCLUSIONS:Current results indicated that, in addition to elastic modulus and plastic hardness, measurement of viscoelastic properties of bone tissue surrounding the implant can provide more detailed information to understand mechanical behavior of an implant system. CLINICAL RELEVANCE:Ability of energy absorption in the interfacial bone tissue can play a significant role in the long-term success of a dental implant system. 10.1007/s00784-016-1734-2
    Comparison of chemically and pharmaceutically modified titanium and zirconia implant surfaces in dentistry: a study in sheep. Langhoff J D,Voelter K,Scharnweber D,Schnabelrauch M,Schlottig F,Hefti T,Kalchofner K,Nuss K,von Rechenberg B International journal of oral and maxillofacial surgery Advanced surface modifications and materials were tested on the same implant geometry. Six types of dental implants were tested for osseointegration after 2, 4 and 8 weeks in a sheep pelvis model. Four titanium implant types were treated with newly developed surface modifications, of which two were chemically and two were pharmacologically modified. One implant was made of zirconia. A sandblasted and acid-etched titanium surface was used as reference. The chemically modified implants were plasma-anodized or coated with calcium phosphate. The pharmacological coatings contained either bisphosphonate or collagen type I with chondroitin sulphate. The implants were evaluated using macroscopic, radiographic and histomorphometric methods. All implants were well osseointegrated at the time of death. All titanium implants had similar bone implant contact (BIC) at 2 weeks (57-61%); only zirconia was better (77%). The main BIC increase was between 2 and 4 weeks. The pharmacologically coated implants (78-79%) and the calcium phosphate coating (83%) showed similar results compared with the reference implant (80%) at 8 weeks. There were no significant differences in BIC. Compared with previous studies the results of all implants were comparatively good. 10.1016/j.ijom.2008.09.008
    Biomechanical and histological behavior of zirconia implants: an experiment in the rat. Kohal Ralf J,Wolkewitz Martin,Hinze Marc,Han Jung-Suk,Bächle Maria,Butz Frank Clinical oral implants research OBJECTIVE:This study aimed at evaluating the integration of zirconia implants in a rat femur model. MATERIAL AND METHODS:Zirconia implants with two distinct surface topographies were compared with titanium implants with similar topographies. Titanium and zirconia implants were placed into the femurs of 42 male Sprague-Dawley rats. Four groups of implants were utilized: machined zirconia implants, zirconia implants with a rough surface, machined titanium implants, and titanium implants with an electrochemically roughened surface. After a healing period of 28 days, the load-bearing capacity between the bone and the implant surface was evaluated by a push-in test. Additionally, after a healing period of 14 and 28 days, respectively, bone tissue specimens containing the implants were processed and histologically analyzed. RESULTS:The mean mineralized bone-to-implant contact showed the highest values after 14 and 28 days for the rough surfaces (titanium: 36%/45%; zirconia: 45%/59%). Also, the push-in test showed higher values for the textured implant surfaces, with no statistical significance between titanium (34 N) and zirconia (45.8 N). CONCLUSIONS:Within the limits of the animal investigation presented, it was concluded that all tested zirconia and titanium implant surfaces were biocompatible and osseoconductive. The presented surface modification of zirconia implants showed no difference regarding the histological and biomechanical results compared with an established electrochemically modified titanium implant surface. 10.1111/j.1600-0501.2008.01656.x
    Time-dependent periimplant bone reaction of acidic monomer-treated injection molded zirconia implants in rabbit tibiae. Shon Won-Jun,Woo Kyung Mi,Kim Hong-Kyun,Kwon Ho Beom,Shin Seung-Yun,Park Young-Seok Implant dentistry PURPOSE:The aim of this study was to evaluate and compare the osseointegration of zirconia implants in rabbit tibiae with and without 10-methacryloyloxydecyl dihydrogen phosphate (MDP) treatment. MATERIALS AND METHODS:Twenty-eight rabbits received a total of 112 external hex-type implants made by the powder injection molding technique with and without MDP treatment before installation in the tibiae. The contact angles on the zirconia implants and zirconia discs before and after MDP application were evaluated. Removal torque (RT) and bone-implant contact (BIC) ratios were measured. RESULTS:The MDP treatment markedly enhanced the hydrophilicity and seemed to alter the topography and chemical composition of the implant and disc surface. As the healing time increases, the BIC and RT were increased in both groups. The MDP-treated implants exhibited higher BIC values than the control implants after 2 and 4 weeks of healing. The RT was higher in MDP-treated implants after 2 weeks of healing but not after 4 weeks of healing. CONCLUSION:The 10-MDP treatments made the surface more hydrophilic and enhanced the osseointegration of the implants in the early healing phase. 10.1097/ID.0000000000000246
    Papilla and alveolar crest levels in immediate versus delayed single-tooth zirconia implants. Kniha K,Kniha H,Möhlhenrich S C,Milz S,Hölzle F,Modabber A International journal of oral and maxillofacial surgery The aim of this study was to determine the correlation between the papilla deficit and the distance between the bone crest at the neighbouring tooth and the contact point of the clinical crown (distance 4) for immediate and delayed zirconia implants. This prospective observational study included 78 patients with 82 implants investigated at the 1-year follow-up. Patients received single-unit zirconia implants (Straumann PURE Ceramic Implant with ZLA surface) that were placed using either the delayed (group A) or immediate (group B) protocol after tooth extraction. The distance of the alveolar crest of the neighbouring tooth to the height of the interdental papilla and the absence of the papilla were also assessed. There was a strong correlation between the papilla deficit and distance 4 in group A (Spearman's rho=0.64). However, in group B, only a weak correlation between the two distances was found (Spearman's rho=0.28). A full soft tissue margin was generated when distance 4 was 7-8mm or less. Delayed implant placement showed a critical distance between the alveolar crest at the neighbouring tooth and the contact point of the crown risking a visible papilla deficit of between 7mm and 8mm. 10.1016/j.ijom.2017.02.007
    Stability of prototype two-piece zirconia and titanium implants after artificial aging: an in vitro pilot study. Kohal Ralf-Joachim,Finke Hans Christian,Klaus Gerold Clinical implant dentistry and related research BACKGROUND:Zirconia oral implants are a new topic in implant dentistry. So far, no data are available on the biomechanical behavior of two-piece zirconia implants. Therefore, the purpose of this pilot investigation was to test in vitro the fracture strength of two-piece cylindrical zirconia implants after aging in a chewing simulator. MATERIALS AND METHODS:This laboratory in vitro investigation comprised three different treatment groups. Each group consisted of 16 specimens. In group 1, two-piece zirconia implants were restored with zirconia crowns (zirconia copings veneered with Triceram; Esprident, Ispringen, Germany), and in group 2 zirconia implants received Empress 2 single crowns (Ivoclar Vivadent AG, Schaan, Liechtenstein). The implants, including the abutments, in the two zirconia groups were identical. In group 3, similar titanium implants were reconstructed with porcelain-fused-to-metal crowns. Eight samples of each group were submitted to artificial aging with a long-term load test in the artificial mouth (chewing simulator). Subsequently, all not artificially aged samples and all artificially aged samples that survived the long-term loading of each group were submitted to a fracture strength test in a universal testing machine. For the pairwise comparisons in the different test groups with or without artificial loading and between the different groups at a given artificial loading condition, the Wilcoxon rank-sum test for independent samples was used. The significance level was set at 5%. RESULTS:One sample of group 1 (veneer fracture), none of group 2, and six samples of group 3 (implant abutment screw fractures) failed while exposed to the artificial mouth. The values for the fracture strength after artificial loading with 1.2 million cycles for group 1 were between 45 and 377 N (mean: 275.7 N), in group 2 between 240 and 314 N (mean: 280.7 N), and in the titanium group between 45 and 582 N (mean: 165.7 N). The fracture strength results without artificial load for group 1 amounted to between 270 and 393 N (mean: 325.1 N), for group 2 between 235 and 321 N (mean: 281.8 N), and between 474 and 765 N (mean: 595.2 N) for the titanium group. The failure mode during the fracture testing in the zirconia implant groups was a fracture of the implant head and a bending/fracture of the abutment screw in the titanium group. CONCLUSIONS:Within the limits of this pilot investigation, the biomechanical stability of all tested prototype implant groups seems to be - compared with the possibly exerted occlusal forces - borderline for clinical use. A high number of failures occurred already during the artificial loading in the titanium group at the abutment screw level. The zirconia implant groups showed irreparable implant head fractures at relatively low fracture loads. Therefore, the clinical use of the presented prototype implants has to be questioned. 10.1111/j.1708-8208.2008.00116.x
    The zirconia implant-bone interface: a preliminary histologic evaluation in rabbits. Hoffmann Oliver,Angelov Nikola,Gallez Fabrice,Jung Ronald E,Weber Franz E The International journal of oral & maxillofacial implants PURPOSE:Zirconia ceramics, a biocompatible material with favorable mechanical properties, has been suggested for use in the manufacture of dental implants instead of the commonly used titanium. Not much data exist on the early healing response around zirconia dental implants. The aim of this study was to give a descriptive histologic assessment of the degree of early bone apposition around zirconia dental implants at 2 and 4 weeks after insertion compared to surface-modified titanium implants. MATERIALS AND METHODS:Four zirconia and 4 titanium implants were placed in New Zealand white male rabbits. One implant was inserted in the condyle of each distal femur. Specimens were harvested at 2 and 4 weeks and processed with light microscopic analysis. The area of bone-implant contact was evaluated histomorphometrically. RESULTS:A high degree of bone apposition could be observed on all implants at both time points. Differences in the percentage of implant surface covered with bone were noted between the 2 time points, with comparable results for the 2 materials. CONCLUSION:The results of this limited histologic study demonstrate a similar rate of bone apposition on zirconia and surface-modified titanium implant surfaces during early healing. To confirm these results, further studies need to be conducted, involving larger sample size at more time points.
    Analysis of Removal Torque of Injection Molded Zirconia Implants; An Experimental Study on Beagles. Oh Gye-Jeong,Ban Jae-Sam,Lim Hyun-Pil,Yun Kwi-Dug,Lee Kwang-Min,Vang Mong-Sook,Yang Hong-So,Kang Seong-Soo,Shin Jin-Ho,Kim Ga-Hyun,Ji Min-Kyung,Park Sang-Won,Fisher John G Journal of nanoscience and nanotechnology This study compared the removal torque between injection molded zirconia implants and titanium implants with resorbable blast media (RBM) surfaces in beagle humeri. Fifteen screw-shaped implants were classified into 3 groups; titanium implant with RBM surface (Group RT), injection molded zirconia implant (Group Zr) and injection molded zirconia implant with sand-blasted surface (Group ZrS). Implants were inserted into beagle humeri. After 12 weeks, removal torque values were measured. The Zr group has a slightly higher removal torque value than the RT and ZrS groups but there were no significant differences among groups. Zirconia implants shows a similar removal torque to RBM titanium implants. This in vivo study showed injection molded zirconia implants could be an alternative to RBM titanium implants in terms of removal torque. 10.1166/jnn.2015.8376
    One-piece zirconia oral implants: one-year results from a prospective case series. 2. Three-unit fixed dental prosthesis (FDP) reconstruction. Kohal Ralf-Joachim,Patzelt Sebastian B M,Butz Frank,Sahlin Herman Journal of clinical periodontology AIM:To evaluate the clinical and radiological outcome of one-piece zirconia oral implants for three-unit fixed dental prosthesis (FDP) replacement after 1 year. MATERIALS:Twenty eight patients were recruited for the investigation and signed an informed consent. All patients were treated with a one-stage implant surgery and a three-unit immediate temporary restoration on two one-piece zirconia implants. The implants were fabricated of yttria-stabilized tetragonal zirconia (y-TZP). The endosseous part of the implants was tapered with a porous surface. A total of 56 implants were inserted in the 28 patients. A total of 12 implants were placed in the upper jaws (six in the anterior area and six in the posterior area) and 44 in mandibles (all in the posterior area). At implant insertion and after 1 year, standardized radiographs were taken to evaluate the peri-implant bone loss. To evaluate any influences from different baseline parameters on the marginal bone loss a univariate analysis was performed. Clinical soft tissue parameters probing depth (PD), clinical attachment level (CAL), modified bleeding index (mBI) and modified plaque index (mPI) were recorded. Implant cumulative survival rates were calculated using actuarial life table analysis. Changes in the clinical variables were assessed using the Wilcoxon Signed Ranks test (PD, CAL) and the Sign test (mBl, mPl). All significance tests were conducted at a 5% level of significance. RESULTS:After 1 year, one implant was lost resulting in a survival rate of 98.2%. The patient was excluded from further analysis. The marginal bone loss after 1 year amounted to 1.95 mm. In 40% of the patients a bone loss of at least 2 mm and in 28% of the patients a loss of more than 3 mm were observed. The PD decreased for implant and tooth sites over time, the values being significantly higher for implants than for teeth. Over 1 year, the CAL increased slightly around the implants and decreased around the teeth. At the 1-year follow-up, the CAL at the implant sites was statistically significantly higher than at the reference teeth. The mBI was significantly lower at implants than at teeth. The same result was found for the plaque index. CONCLUSIONS:A high frequency of increased radiographic bone loss (>2 mm) after 1 year around the presented one-piece zirconia implant system was found. The bone loss seems to be higher compared to the very limited availability of zirconia implant data. Therefore, within the limits of the present investigation, it may be concluded that the presented zirconia implant system possibly performs inferior to conventional titanium implants and to other zirconia implants regarding peri-implant bone loss. 10.1111/jcpe.12093
    Influence of gaseous ozone in peri-implantitis: bactericidal efficacy and cellular response. An in vitro study using titanium and zirconia. Hauser-Gerspach Irmgard,Vadaszan Jasminka,Deronjic Irma,Gass Catiana,Meyer Jürg,Dard Michel,Waltimo Tuomas,Stübinger Stefan,Mauth Corinna Clinical oral investigations Dental implants are prone to bacterial colonization which may result in bone destruction and implant loss. Treatments of peri-implant disease aim to reduce bacterial adherence while leaving the implant surface intact for attachment of bone-regenerating host cells. The aims of this study were to investigate the antimicrobial efficacy of gaseous ozone on bacteria adhered to various titanium and zirconia surfaces and to evaluate adhesion of osteoblast-like MG-63 cells to ozone-treated surfaces. Saliva-coated titanium (SLA and polished) and zirconia (acid etched and polished) disks served as substrates for the adherence of Streptococcus sanguinis DSM20068 and Porphyromonas gingivalis ATCC33277. The test specimens were treated with gaseous ozone (140 ppm; 33 mL/s) for 6 and 24 s. Bacteria were resuspended using ultrasonication, serially diluted and cultured. MG-63 cell adhesion was analyzed with reference to cell attachment, morphology, spreading, and proliferation. Surface topography as well as cell morphology of the test specimens were inspected by SEM. The highest bacterial adherence was found on titanium SLA whereas the other surfaces revealed 50-75% less adherent bacteria. P. gingivalis was eliminated by ozone from all surfaces within 24 s to below the detection limit (≥99.94% reduction). S. sanguinis was more resistant and showed the highest reduction on zirconia substrates (>90% reduction). Ozone treatment did not affect the surface structures of the test specimens and did not influence osteoblastic cell adhesion and proliferation negatively. Titanium (polished) and zirconia (acid etched and polished) had a lower colonization potential and may be suitable material for implant abutments. Gaseous ozone showed selective efficacy to reduce adherent bacteria on titanium and zirconia without affecting adhesion and proliferation of osteoblastic cells. This in vitro study may provide a solid basis for clinical studies on gaseous ozone treatment of peri-implantitis and revealed an essential base for sufficient tissue regeneration. 10.1007/s00784-011-0603-2
    Influence of surface topography and surface physicochemistry on wettability of zirconia (tetragonal zirconia polycrystal). Noro Akio,Kaneko Morio,Murata Isao,Yoshinari Masao Journal of biomedical materials research. Part B, Applied biomaterials Surface modification technologies are available for tetragonal zirconia polycrystal (TZP) to enhance its bioactivity and osseointegration capability. The surface wettability of an implant material is one of the important factors in the process of osseointegration, possibly regulating protein adsorption, and subsequent cell behavior. The aim of this study was to clarify the effect of topographical or physicochemical modification of TZP ceramics on wettability to determine the potential of such treatment in application to implants. Several types of surface topography were produced by alumina blasting and acid etching with hydrofluoric acid; surface physicochemistry was modified with oxygen (O(2)) plasma, ultraviolet (UV) light, or hydrogen peroxide treatment. The obtained specimens were also subjected to storage under various conditions to evaluate their potential to maintain superhydrophilicity. The results showed that surface modification of surface topography or physicochemistry, especially of blast/acid etching as well as O(2) plasma and UV treatment, greatly increased the surface wettability, resulting in superhydrophilicity. X-ray photoelectron spectroscopy revealed that a remarkable decrease in carbon content and the introduction of hydroxyl groups were responsible for the observed superhydrophilicity. Furthermore, superhydrophilicity was maintained, even after immersion in an aqueous solution, an important consideration in the clinical application of this technology. 10.1002/jbm.b.32846
    Microstructured zirconia surfaces modulate osteogenic marker genes in human primary osteoblasts. Bergemann Claudia,Duske Kathrin,Nebe J Barbara,Schöne André,Bulnheim Ulrike,Seitz Hermann,Fischer Jens Journal of materials science. Materials in medicine In dentistry, zirconia has been used since the early 1990s for endodontic posts, more recently for implant abutments and frameworks for fixed dental prostheses. Zirconia is biocompatible and mechanically strong enough to serve as implant material for oral implants. Although several zirconia implant systems are available, currently the scientific and clinical data for zirconia implants are not sufficient to recommend them for routine clinical use. Here the influence of microstructured yttria-stabilized zirconia (YZ) on human primary osteoblast (HOB) behavior was determined. YZ surfaces were treated by sandblasting (YZ-S), acid etching (YZ-SE) and additionally heat treatment (YZ-SEH). Morphological changes of HOB were determined by scanning electron microscopy. Actin cytoskeleton was investigated by laser scanning microscopy and analyzed by novel actin quantification software. Differentiation of HOB was determined by real time RT-PCR. Improved mechanical interlocking of primary HOB into the porous microstructure of the acid etched and additionally heat treated YZ-surfaces correlates with drastically increased osteocalcin (OCN) gene expression. In particular, OCN was considerably elevated in primary HOB after 3 days on YZ-SE (13-fold) as well as YZ-SEH (12-fold) surfaces. Shorter actin filaments without any favored orientation on YZ-SE and YZ-SEH surfaces are associated with higher roughness (Ra) values. Topographically modified yttria-stabilized zirconia is a likely material for dental implants with cell stimulating properties achieving or actually exceeding those of titanium. 10.1007/s10856-014-5350-x
    One-Piece Zirconia Ceramic versus Titanium Implants in the Jaw and Femur of a Sheep Model: A Pilot Study. Siddiqi A,Duncan W J,De Silva R K,Zafar S BioMed research international Reports have documented titanium (Ti) hypersensitivity after dental implant treatment. Alternative materials have been suggested including zirconia (Zr) ceramics, which have shown predictable osseointegration in animal studies and appear free of immune responses. The aim of the research was to investigate the bone-to-implant contact (BIC) of one-piece Zr, compared with one-piece Ti implants, placed in the jaws and femurs of domestic sheep. Ten New Zealand mixed breed sheep were used. A One-piece prototype Ti (control) and one Zr (test) implant were placed in the mandible, and one of each implant (Ti and Zr) was placed into the femoral epicondyle of each animal. The femur implants were submerged and unloaded; the mandibular implants were placed using a one-stage transgingival protocol and were nonsubmerged. After a healing period of 12 weeks, %BIC was measured. The overall survival rate for mandibular and femur implants combined was 87.5%. %BIC was higher for Zr implants versus Ti implants in the femur (85.5%, versus 78.9%) ( = 0.002). Zirconia implants in the mandible showed comparable %BIC to titanium implants (72.2%, versus 60.3%) ( = 0.087). High failure rate of both Zr and Ti one-piece implants in the jaw could be attributed to the one-piece design and surface characteristics of the implant that could have influenced osseointegration. Further clinical trials are recommended to evaluate the performance of zirconia implants under loading conditions. 10.1155/2016/6792972
    Collagen fiber orientation around machined titanium and zirconia dental implant necks: an animal study. Tetè Stefano,Mastrangelo Filiberto,Bianchi Andrea,Zizzari Vincenzo,Scarano Antonio The International journal of oral & maxillofacial implants PURPOSE:To evaluate in vivo collagen fiber behavior around two different dental implant necks placed in the mandibular bone of adult pigs. MATERIALS AND METHODS:Scanning electron microscopic (SEM) and profilometric analyses were performed on both types of implant necks to evaluate the different surface morphology. Ten dental implants with machined titanium necks and 20 implants with zirconia necks were inserted into the mandibles of five adult pigs. Three months later, the animals were sacrificed; samples from the peri-implant mucosa were obtained and prepared for histologic analysis. Evaluation of collagen fiber orientation in the connective tissue surrounding the implant necks was performed by polarized light microscopy. Inflammation in the peri-implant soft tissues was also measured via the Gingival Index. RESULTS:Postoperative healing was uneventful; all implants, except for one of each type, were osseointegrated after 3 months. SEM and profilometric analyses confirmed that zirconia necks showed Ra, Rq, and Rz values that were lower than those seen around the titanium necks. Histologic observation indicated that collagen fiber orientation was similar for both types of implants. The majority of fibers showed a parallel or parallel-oblique orientation to the implant surface for all samples. Implants that were not osseointegrated, as determined by clinical evaluation, showed inflammatory infiltrate, whereas healthy connective tissue was found around all the other implant necks. CONCLUSIONS:Collagen fiber orientation was similar, regardless of implant material, demonstrating a predominantly parallel or parallel-oblique pattern. Moreover, zirconia, which is used as a transgingival collar on some implants, showed connective tissue adhesion that was similar to that seen on the machined titanium surface, but demonstrated limited plaque formation and may provide better esthetics.
    Biomechanical and histomorphometric evaluation of osseointegration of fusion-sputtered zirconia implants. Salem Noha A,Abo Taleb Ahmed L,Aboushelib Moustafa N Journal of prosthodontics : official journal of the American College of Prosthodontists PURPOSE:The aim of this study was to evaluate osseointegration of fusion-sputtered zirconia implants in comparison with sandblasted, acid-etched titanium implants in a biomechanical and histomorphometric study. MATERIALS AND METHODS:Sixty zirconia implants were manufactured using CAD/CAM. Half received fusion sputtering surface treatment through spraying the green body implants with a jet of zirconia suspension. Standard Ti implants of the same shape and dimensions served as control. Thirty adult New Zealand white male rabbits were used in this study. Each animal received one fusion-sputtered and one Ti implant in one femur site and control zirconia in the other, for a healing period of 4, 8, and 12 weeks. At each healing time, a removal torque (RTQ) test was used to assess implant stability, while histological and histometric analyses were used to evaluate osseointegration. RESULTS:Fusion-sputtered zirconia implants demonstrated a statistically higher mean RTQ than control zirconia. When compared to Ti, however, although still higher, the differences were not significant. Histomorphometric evaluation revealed significantly greater bone-implant contact for fusion-sputtered zirconia implants compared to Ti after 4 and 8 weeks of healing time; however, at 12 weeks, the difference did not reach statistical significance. There were no significant differences in the measured bone density between fusion-sputtered and Ti implants, although the difference was significant when compared to the control zirconia. CONCLUSION:Fusion-sputtered zirconia implants demonstrated a degree of osseointegration and interfacial biomechanical stability comparable to Ti implants. 10.1111/j.1532-849X.2012.00940.x
    Reconciling in vivo and in vitro kinetics of the polymorphic transformation in zirconia-toughened alumina for hip joints: I. Phenomenology. Bal B Sonny,Zhu Wenliang,Zanocco Matteo,Marin Elia,Sugano Nobuhiko,McEntire Bryan J,Pezzotti Giuseppe Materials science & engineering. C, Materials for biological applications Exploitation of the toughening effect induced by polymorphic phase transformation of zirconia in zirconia-toughened alumina (ZTA) requires the composite being properly designed and carefully manufactured. A sound algorithm for predicting phase stability along with strict control over manufacturing steps are required in order to prevent possible in vivo surface degradation or implant fracture. This paper is the first in a series of three monographs, which aim at: (i) statistically comparing the in vitro/in vivo phenomenology of surface-metastability for currently marketed ZTA femoral heads; (ii) refining pre-existing theoretical models for predicting in vivo zirconia phase metastability via the use of accelerated in vitro ageing experiments; and, (iii) providing a rationale for the mechanism(s) involved with the observed in vivo surface metastability. This initial paper of a series of three, which specifically deals with item (i), shows discrepancies between the levels of polymorphic phase transformation detected in ZTA retrievals and in vitro predictions, and attempts a phenomenological analysis of the reasons behind such discrepancies. Moreover, marked inhomogeneities are also found among as-manufactured components through different years of production. The phenomenology of retrievals' data suggests key roles for both the presence of metallic stain and the initial value of monoclinic volume fraction. 10.1016/j.msec.2016.11.059
    Effect of heat treatment and in vitro aging on the microstructure and mechanical properties of cold isostatic-pressed zirconia ceramics for dental restorations. Vatali Anna,Kontonasaki Eleana,Kavouras Panagiotis,Kantiranis Nikolaos,Papadopoulou Lambrini,Paraskevopoulos Konstantinos K M,Koidis Petros Dental materials : official publication of the Academy of Dental Materials OBJECTIVES:The temperature variations during the veneering firing cycles of a zirconia dental ceramic can negatively affect its mechanical properties. A possible synergistic effect of both heat-treatment and aging while exposed to the oral environment could result to catastrophic failure. The aim of the present study was to investigate the effect of heat treatment followed during veneering and in vitro aging on the mechanical and microstructural properties of zirconia dental ceramics. METHODS:Three specimens from each of two zirconia blocks (Ivoclar IPS e.max ZirCAD (IV) and Wieland ZENO Zr (WI)) were cut by CAD/CAM technology, fully sintered and polished. Each one was cut in four equal parts. One part was used as control (C), one was heat-treated (H), one was aged (A) (134°C, 2bar, 10h) and one was heat-treated and subsequently aged (HA). The mechanical properties (nano-hardness (H) and elastic modulus (E*)) were investigated by nano-indentation tests while the surface characterization was carried out with XRD, FTIR and SEM. RESULTS:Different treatments on IV and WI samples resulted in a reduction of both H and E* values, however the differences were not statistically significant (p>0.05). The combination of treatments imposes an overall effect (p<0.001), enhancing the influence on both H and E* values. This reduction in mechanical properties was followed by an increase of monoclinic content. Greater variations in both H and E* values were recorded for WI samples. SIGNIFICANCE:The clinical performance of zirconia dental ceramics may be affected during firing and aging resulting in increased probability of failure. 10.1016/j.dental.2014.05.017
    Morphology, proliferation, and gene expression of gingival fibroblasts on Laser-Lok, titanium, and zirconia surfaces. Esfahanizadeh Nasrin,Motalebi Sara,Daneshparvar Niloufar,Akhoundi Nasrin,Bonakdar Shahin Lasers in medical science Soft tissue seal plays a critical role in long-term success of dental implants, and the effects of implant surface treatments such as laser ablation have been a topic of particular interest in this respect. Considering the existing controversy regarding soft tissue behavior in contact with implant surfaces, this study sought to assess the morphology, proliferation, and gene expression of human gingival fibroblasts (HGFs) on different abutment surfaces. In this in vitro, experimental study, HGFs were cultured on 45 discs (Laser-Lok, titanium, and zirconia). Cell morphology, proliferation rate, and interleukin 10 (IL-10), tumor necrosis factor alpha (TNFα), fibronectin, and integrin gene expressions were assessed by electron microscopy, methyl thiazol tetrazolium (MTT) assay, and real-time polymerase chain reaction (PCR), respectively. Data were analyzed using ANOVA and the Kruskal-Wallis H test. Fibroblast attachment was noted in all the three groups. Spindle-shaped cells with pseudopod-like processes were more frequently seen in the Laser-Lok group. Cell proliferation was significantly higher in the Laser-Lok group compared to those in the other groups (P = 0.0002). Significant differences were found in the expression of IL-10, TNFα, fibronectin, and integrin genes among the groups (P < 0.01). Within the limitations of this study, HGFs on Laser-Lok surfaces had a more mature morphology and greater proliferation and differentiation as compared to those on zirconia and titanium surfaces. This indicates better attachment of these cells to laser-modified surfaces, creating a more efficient soft tissue seal around dental implants. 10.1007/s10103-016-1927-6
    Towards long lasting zirconia-based composites for dental implants. Part I: innovative synthesis, microstructural characterization and in vitro stability. Palmero Paola,Fornabaio Marta,Montanaro Laura,Reveron Helen,Esnouf Claude,Chevalier Jérôme Biomaterials In order to fulfill the clinical requirements for strong, tough and stable ceramics used in dental applications, we designed and developed innovative zirconia-based composites, in which equiaxial α-Al2O3 and elongated SrAl12O19 phases are dispersed in a ceria-stabilized zirconia matrix. The composite powders were prepared by an innovative surface coating route, in which commercial zirconia powders were coated by inorganic precursors of the second phases, which crystallize on the zirconia particles surface under proper thermal treatment. Samples containing four different ceria contents (in the range 10.0-11.5 mol%) were prepared by carefully tailoring the amount of the cerium precursor during the elaboration process. Slip cast green bodies were sintered at 1450 °C for 1 h, leading to fully dense materials. Characterization of composites by SEM and TEM analyses showed highly homogeneous microstructures with an even distribution of both equiaxial and elongated-shape grains inside a very fine zirconia matrix. Ce content plays a major role on aging kinetics, and should be carefully controlled: sample with 10 mol% of ceria were transformable, whereas above 10.5 mol% there is negligible or no transformation during autoclave treatment. Thus, in this paper we show the potential of the innovative surface coating route, which allows a perfect tailoring of the microstructural, morphological and compositional features of the composites; moreover, its processing costs and environmental impacts are limited, which is beneficial for further scale-up and real use in the biomedical field. 10.1016/j.biomaterials.2015.01.018
    Bone formation around zirconia implants combined with rhBMP-2 gel in the canine mandible. Lee Byung-Chul,Yeo In-Sung,Kim Dae-Joon,Lee Jai-Bong,Kim Sung-Hun,Han Jung-Suk Clinical oral implants research OBJECTIVE:The aim of this study was to estimate the effects of zirconia implants and recombinant human bone morphogenetic protein-2 (rhBMP-2) gel on the acceleration of local bone formation and osseointegration in the canine mandible. MATERIALS AND METHODS:Four groups of 48 implants with identical geometry were installed in the mandibles of beagle dogs: alumina-blasted zirconia implants applied with rhBMP-2, alumina-blasted zirconia implants applied with demineralized bone matrix (DBM), alumina-blasted zirconia implants, and resorbable blast media-treated titanium (Ti) implants. For the first two groups, zirconia implants were inserted after the surgical sites were filled with rhBMP-2 or DBM gel. For the other two groups, zirconia or Ti implants were installed with no adjunctive treatment. Fluorescent bone markers were administered to monitor bone remodeling at weeks 2, 4, and 5 postimplantation. After healing periods of 3 weeks and 6 weeks, the animals were sacrificed, and fluorescent microscopy, histology, and histomorphometric analyses were performed. RESULTS:Fluorescent microscopy showed that bone formation around the zirconia implants installed with rhBMP-2 gel was the most prominent at 2 weeks postimplantation, while the Ti implants acquired bone apposition mainly at week 5. No significant differences were found in bone area among the groups (P > 0.05). The zirconia implants showed similar bone-to-implant contact to the Ti implants. There were no significant differences in bone-to-implant contact between the zirconia implants with rhBMP-2 gel and those with DBM (P > 0.05). CONCLUSIONS:The zirconia implants with alumina-blasted surfaces may achieve osseointegration in much the same manner as the well-established Ti implants. The area influenced by rhBMP-2 gel, including the alveolar crest, may cause active remodeling and early bone formation. 10.1111/clr.12004
    Surface characterization of monolithic zirconia submitted to different surface treatments applying optical interferometry and raman spectrometry. Tzanakakis Emmanouil,Kontonasaki Eleana,Voyiatzis George,Andrikopoulos Konstantinos,Tzoutzas Ioannis Dental materials journal This study evaluated roughness parameters and phase transformation of monolithic zirconia ceramics after various mechanical and laser thermal treatments. Fully sintered monolithic zirconia cylinder specimens were divided to five groups, according to the applied surface treatment: CL: control, GB: grit-blasted with glass particles. AL50: grit-blasted with 50 μm alumina particles, AL90: grit-blasted with 90 μm dyed-alumina particles and FEML: subjected to femto laser thermal treatment. Six roughness parameters (Sa, Sq, Sz, Sci, Svi and Sdr) were measured by optical profilometry. Phase transformation in zirconia was determined by micro-Raman spectroscopy. The highest roughness values were recorded in AL90 and FEML groups, followed by AL50. AL90 presented statistically higher monoclinic phase content compared to all other groups. Control and GB groups presented similar roughness without phase transformation. Laser thermal treatment causes minimal destruction of the zirconia surface, and can be suggested as an alternative to other roughening treratments, for enhancing the adhesive potential to dentin. 10.4012/dmj.2018-358
    Osseointegration of a Zirconia Implant: A Histologic Assessment. Schepke Ulf,Meijer Gert J,Meijer Henny Ja,Walboomers X Frank,Cune Marco The International journal of prosthodontics PURPOSE:The aim of this study was to describe the histologic and histomorphometric features of a retrieved, functional endosseous zirconia implant in a human subject. MATERIALS AND METHODS:A maxillary zirconia implant (ZV3) placed in a 52-year-old man was retrieved after 2 years of uncompromised service and prepared for light microscopic evaluation. RESULTS:Histologic examination demonstrated good osseointegration. Bone contact measurements revealed a mean percentage of bone-to-implant contact of 55.8% (SD 3.8%). CONCLUSION:The histologic data provide further evidence of the potential of zirconia implants to osseointegrate to a similar degree as titanium in humans. 10.11607/ijp.5230
    Histological and Histomorphometric Evaluation of Zirconia Dental Implants Modified by Femtosecond Laser versus Titanium Implants: An Experimental Study in Fox Hound Dogs. Calvo-Guirado Jose Luis,Aguilar-Salvatierra Antonio,Delgado-Ruiz Rafael Arcesio,Negri Bruno,Fernández María Piedad Ramírez,Maté Sánchez de Val José Eduardo,Gómez-Moreno Gerardo,Romanos Georgios E Clinical implant dentistry and related research PURPOSE:This study applied femtosecond laser technology to zirconia dental implants (Bredent GmbH & Co.KG, Senden, Germany) to generate a surface texture of microgrooves over the entire intraosseous surface, analyzing its behavior in an in vivo model in comparison with titanium implants with sandblasted and acid-etched surfaces. MATERIALS AND METHODS:The study used six American Fox Hound dogs. Each received four implants per hemi-mandible, making a total of eight implants per animal. The 48 immediate loaded implants were divided into two groups of 24 titanium implants (control group) and 24 zirconia implants (study/test group), distributed randomly. Bone-to-implant contact (BIC) values and crestal resorption were determined at 1 and 3 months, also measuring calcium, phosphorous, and carbon concentrations by means of energy dispersive x-ray. RESULTS:BIC percentages after 30 days were 51.36% for titanium implants and 44.68% for zirconia implants. After 90 days, values increased to 61.73% in titanium and 47.94% in zirconia implants. After 30 days, there was more crestal bone lost in the titanium group (0.77 mm) compared with the zirconia group (0.01 mm). After 90 days, zirconia implants showed greater marginal bone resorption (1.25 mm) compared with the titanium group (0.37 mm). CONCLUSIONS:The present study shows that zirconia implants with modified surfaces can produce good osseointegration values when compared with titanium implants in terms of BIC and crestal bone resorption at 1 and 3 months. 10.1111/cid.12162
    Zirconia in dental implantology: A review. Apratim Abhishek,Eachempati Prashanti,Krishnappa Salian Kiran Kumar,Singh Vijendra,Chhabra Saurabh,Shah Sanket Journal of International Society of Preventive & Community Dentistry BACKGROUND:Titanium has been the most popular material of choice for dental implantology over the past few decades. Its properties have been found to be most suitable for the success of implant treatment. But recently, zirconia is slowly emerging as one of the materials which might replace the gold standard of dental implant, i.e., titanium. MATERIALS AND METHODS:Literature was searched to retrieve information about zirconia dental implant and studies were critically analyzed. PubMed database was searched for information about zirconia dental implant regarding mechanical properties, osseointegration, surface roughness, biocompatibility, and soft tissue health around it. The literature search was limited to English language articles published from 1975 to 2015. RESULTS:A total of 45 papers met the inclusion criteria for this review, among the relevant search in the database. CONCLUSION:Literature search showed that some of the properties of zirconia seem to be suitable for making it an ideal dental implant, such as biocompatibility, osseointegration, favourable soft tissue response and aesthetics due to light transmission and its color. At the same time, some studies also point out its drawbacks. It was also found that most of the studies on zirconia dental implants are short-term studies and there is a need for more long-term clinical trials to prove that zirconia is worth enough to replace titanium as a biomaterial in dental implantology. 10.4103/2231-0762.158014
    Peptide-functionalized zirconia and new zirconia/titanium biocermets for dental applications. Fernandez-Garcia Elisa,Chen Xi,Gutierrez-Gonzalez Carlos F,Fernandez Adolfo,Lopez-Esteban Sonia,Aparicio Conrado Journal of dentistry OBJECTIVE:Titanium materials have been functionalized with biomolecules as a modern strategy to incorporate bioactive motifs that will expand and improve their biomedical applications. Here, we have biofunctionalized biomaterials based on zirconia of much interest for dentistry: the widely used bioceramic 3Y-TZP and a newly developed 3Y-TZP/Ti biocermet. METHODS:The biosurfaces were activated, silanized, and functionalized with coatings made of oligopeptides. Surface activation by plasma or alkaline-etching was optimized. The surfaces were coated by tethering a purposely-designed RGD-containing peptide. We selected this oligopeptide as a model peptide to validate the effectiveness of the biofunctionalization process. Successful treatments after each step of the process were assessed by surface physical and chemical characterization with water contact angles and XPS, respectively. Coatings' stability was evaluated after 2h sonication in water. Pre-osteoblasts adhesion on the functionalized surfaces was also studied. RESULTS:10-min air-plasma treatment effectively activated all types of materials with no detrimental effects on the material structure and hardness. Nitrogen XPS-peak confirmed that RGD-peptides were chemically-attached on the silanized samples. This was further confirmed by visualizing the functionalized surfaces with flourescence-labelled RGD-peptides before and after ultrasonication. Furthermore, RGD-functionalized surfaces significantly enhanced osteoblast adhesion on all types of substrates, which demonstrated their successful bioactivation. CONCLUSIONS:We successfully developed stable functional biocoatings on zirconia and biocermets made of oligopeptides. Surface bioactivation of zirconia-containing components for dental implant applications will enable their improved clinical performance by incorporating signalling oligopeptides to accelerate osseointegration, improving permucosal sealing, and/or incorporating antimicrobial properties to prevent peri-implant infections. 10.1016/j.jdent.2015.06.002
    Complete mouth reconstruction with implant-supported fixed partial dental prostheses fabricated with zirconia frameworks: a 4-year clinical follow-up. Puri Shweta,Parciak Ewa C,Kattadiyil Mathew T The Journal of prosthetic dentistry Few scientific reports regarding the success of complete mouth partial fixed dental prostheses frameworks fabricated with zirconia are available, especially when dental implants serve as the abutments. A complete mouth reconstruction with zirconia frameworks veneered with feldspathic porcelain is reported involving a 65-year-old white woman who presented with partial edentulism and an unrestorable remaining dentition. After examination, 14 implants were planned (8 in the maxillary arch and 6 in the mandibular arch), and implant-supported zirconia framework screw-retained partial fixed dental prostheses (ISZPFDPs) were fabricated and made in sections for easier retrievability and management. No major complications were encountered during follow-up appointments at 6-month intervals for 4 years. However, minor fractures of the veneering ceramic were noted 4 years after placement. The ISZPFDPs were well accepted by the patient and had a favorable outcome in terms of patient acceptability and success, despite some complications. 10.1016/j.prosdent.2013.11.016
    Pilot clinical and histologic evaluations of a two-piece zirconia implant. Nevins Myron,Camelo Marcelo,Nevins Marc L,Schupbach Peter,Kim David M The International journal of periodontics & restorative dentistry An investigation was conducted to evaluate the clinical and histologic results of bone and soft tissue healing around a two-piece zirconia dental implant in a human model. A healthy female patient requiring tooth replacement with dental implants received a two-piece zirconia implant together with conventional titanium implants to be implemented in a prosthesis. Clinical and radiographic evaluations at 6 months revealed stable osseointegrated zirconia and titanium dental implants. Light microscopy and backscatter scanning electron microscopic analyses confirmed the biocompatibility and achievement of osseointegration, in addition to maintenance of the crestal bone level. The findings suggest that the bone-to-implant contact with a zirconia implant surface is sufficient to provide clinical and histologic evidence of osseointegration. The biopsied two-piece zirconia dental implant with platform switching demonstrated osseointegration occlusal to the implant-abutment junction, eliminating the significance of the microgap.
    Influence of a zirconia sandblasting treated surface on peri-implant bone healing: An experimental study in sheep. Bacchelli Beatrice,Giavaresi Gianluca,Franchi Marco,Martini Désirée,De Pasquale Viviana,Trirè Alessandra,Fini Milena,Giardino Roberto,Ruggeri Alessandro Acta biomaterialia A sandblasting process with round zirconia (ZrO(2)) particles might be an alternative surface treatment to enhance the osseointegration of titanium dental implants. Our previous study on sheep compared smooth surface titanium implants (control) with implant surfaces sandblasted with two different granulations of ZrO(2). As the sandblasted surfaces proved superior, the present study further compared the ZrO(2) surface implant with other surface treatments currently employed: machined titanium (control), titanium oxide plasma sprayed (TPS) and alumina sandblasted (Al-SL) at different times after insertion (2, 4 and 12weeks). Twelve sheep were divided into three groups of four animals each and underwent implant insertion in tibia cortical bone under general anaesthesia. The implants with surrounding tissues were subjected to histology, histomorphometry, scanning electron microscopy and microhardness tests. The experimentation indicated that at 2weeks Zr-SL implants had the highest significant bone ingrowth (p<0.05) compared to the other implant surfaces, and a microhardness of newly formed bone inside the threads significantly higher than that of Ti. The present work shows that the ZrO(2) treatment produces better results in peri-implant newly formed bone than Ti and TPS processing, whereas its performance is similar to the Al-SL surface treatment. 10.1016/j.actbio.2009.01.024
    Zirconia versus titanium in dentistry: A review. Hanawa Takao Dental materials journal This review scientifically compares the properties of zirconia and titanium, but does not identify the best among them as an implant material. Surface treatment and modification to improve tissue bonding and inhibit bacterial adhesion are not considered in this review. The mechanical properties of titanium are superior to those of zirconia; some studies have shown that zirconia can be used as a dental implant, especially as an abutment. Extensive surface treatment research is ongoing to inhibit bacterial adhesion and improve osseointegration and soft tissue adhesion phenomena which make it difficult to evaluate properties of the materials themselves without surface treatment. Osseointegration of titanium is superior to that of zirconia itself without surface treatment; after surface treatment, both materials show comparable osseointegration. The surface morphology is more important for osseointegration than the surface composition. To inhibit bacterial adhesion, zirconia is superior to titanium, and hence, more suitable for abutments. Both materials show similar capability for soft tissue adhesion. 10.4012/dmj.2019-172
    Osseointegration of zirconia implants with different surface characteristics: an evaluation in rabbits. Hoffmann Oliver,Angelov Nikola,Zafiropoulos Gregory-George,Andreana Sebastiano The International journal of oral & maxillofacial implants PURPOSE:Zirconia ceramics are a viable alternative to titanium for use as dental implants. However, the smooth surface of zirconia means that longer healing periods are needed to accomplish osseointegration compared to roughened titanium surfaces. Surface modifications can be used to increase the roughness of zirconia. The aim of this study was to assess histologically and compare the degree of early bone apposition around zirconia dental implants with sandblasted, sintered, or laser-modified surfaces to that seen around surface-modified titanium implants. Removal torque was also measured and compared. MATERIALS AND METHODS:Ninety-six implants--24 each of four types (sintered zirconia, laser-modified zirconia, sandblasted zirconia, and acid-etched titanium)--were placed in 48 New Zealand White female rabbits. One implant was inserted in each distal femur. Half of the specimens were harvested at 6 or 12 weeks and processed for light microscopic analysis; the area of bone-to-implant contact was measured morphometrically. The other half were evaluated for removal torque at 6 and 12 weeks. RESULTS:No statistically significant differences existed in bone apposition between the different surfaces at either time point. Differences in removal torque were significantly different between titanium and sandblasted zirconia and between sintered zirconia and sandblasted zirconia, with the first mentioned demonstrating a higher torque value at 6 weeks. At 12 weeks, the only significant difference in removal torque was between titanium and sandblasted zirconia, with titanium demonstrating the higher value. CONCLUSION:Comparable rates of bone apposition in the zirconia and titanium implant surfaces at 6 and 12 weeks of healing were observed. Removal torque values were similar for all implants with a roughened surface.
    Cytocompatibility of Titanium, Zirconia and Modified PEEK after Surface Treatment Using UV Light or Non-Thermal Plasma. Guo Linna,Smeets Ralf,Kluwe Lan,Hartjen Philip,Barbeck Mike,Cacaci Claudio,Gosau Martin,Henningsen Anders International journal of molecular sciences A number of modifications have been developed in order to enhance surface cytocompatibility for prosthetic support of dental implants. Among them, ultraviolet (UV) light and non-thermal plasma (NTP) treatment are promising methods. The objective of this study was to compare the effects of UV light and NTP on machined titanium, zirconia and modified polyetheretherketone (PEEK, BioHPP) surfaces in vitro. Machined samples of titanium, zirconia and BioHPP were treated by UV light and NTP of argon or oxygen for 12 min each. Non-treated disks were set as controls. A mouse fibroblast and a human gingival fibroblast cell line were used for in vitro experiments. After 2, 24 and 48 h of incubation, the attachment, viability and cytotoxicity of cells on surfaces were assessed. Results: Titanium, zirconia and BioHPP surfaces treated by UV light and oxygen plasma were more favorable to the early attachment of soft-tissue cells than non-treated surfaces, and the number of cells on those treated surfaces was significantly increased after 2, 24 and 48 h of incubation ( < 0.05). However, the effects of argon plasma treatment on the cytocompatibility of soft tissue cells varied with the type of cells and the treated material. UV light and oxygen plasma treatments may improve the attachment of fibroblast cells on machined titanium, zirconia and PEEK surfaces, that are materials for prosthetic support of dental implants. 10.3390/ijms20225596
    Biomechanical and histomorphometric comparison between zirconia implants with varying surface textures and a titanium implant in the maxilla of miniature pigs. Gahlert M,Gudehus T,Eichhorn S,Steinhauser E,Kniha H,Erhardt W Clinical oral implants research BACKGROUND:Mechanical properties and biocompatibility make zirconia ceramics suitable implant material. The characteristics of tooth-color like, the ability to be machined and the low plaque affinity make zirconia especially suitable as a dental implant material. The influence of surface modification on the osseointegration of this material has not been extensively investigated. PURPOSE:Long-term investigations with titanium implants have shown superior biomechanical results with the sandblasted acid-etched (SLA) surface, demonstrating a high bone-implant interaction. The objective of this study was to compare two different zirconia surface topographies biomechanically and histologically with the well-documented titanium SLA surface. MATERIAL AND METHODS:Zirconia implants with either a machined (ZrO2m) or a sandblasted (rough, ZrO2r) surface were manufactured with the exact same cylindrical shape with a standard ITI thread configuration as the SLA titanium implants. The incisors 2 and 3 were removed from both sides of the maxillae of 13 adult miniature pigs and the tissues left to heal for 6 months. After this time period the animals received a total of 78 implants using a randomized scheme, with the titanium SLA implant used as an only individual reference. After healing periods of 4, 8, and 12 weeks 20, 24, and 25 implants, respectively, were subjected to removal torque tests (RTQ) as the main biomechanical analysis of the of the study. A fewer number was resected on bloc, embedded in methylmethacrylat and analyzed for their direct bone apposition under a light microscope. RESULTS:Surface analysis revealed the highest surface roughness for the SLA-implant, followed by ZrO2r and ZrO2m. The turned ZrO2m implants showed statistically significant lower RTQ values than the other two implants types after 8 and 12 weeks, while the SLA implant showed significantly higher RTQs values than ZrO2r surface after 8 weeks. Differences in the bone apposition were observed in the histomorphometric analysis using light microscopy for all surfaces at any time point. CONCLUSION:The findings suggest that ZrO2r implants can achieve a higher stability in bone than ZrO2m implants. Roughening the turned zirconia implants enhances bone apposition and has a beneficial effect on the interfacial shear strength. 10.1111/j.1600-0501.2007.01401.x
    The Effect of UV Treatment on the Osteoconductive Capacity of Zirconia-Based Materials. Brezavšček Miha,Fawzy Ahmed,Bächle Maria,Tuna Taskin,Fischer Jens,Att Wael Materials (Basel, Switzerland) OBJECTIVE:Improvements in the bioactivity of zirconia implants for accelerated healing and reduced morbidity have been of continuing interest in the fields of dentistry and orthopedic surgery. The aim of the present study was to examine whether UV treatment increases the osteoconductivity of zirconia-based materials. MATERIALS AND METHODS:Smooth and rough zirconia-based disks and cylindrical implants were treated with UV light for 15 min and subsequently placed in rat femurs. Surface characterization was performed using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle measurements. RESULTS:In vivo histomorphometry revealed that the percentage of bone-implant contact and the amount of bone volume, formed around UV-treated implants, increased by 3-7-fold for smooth surfaces and by 1.4-1.7-fold for rough surfaces compared to non-treated specimens at Weeks 2 and 4 of healing, respectively. A biomechanical test showed that UV treatment accelerated the establishment of bone-zirconia integration and enhanced the strength of the bone-implant interface by two-fold. Additionally, surface characterization of the zirconia disks revealed that UV treatment decreased the amount of surface carbon and converted the hydrophilic status from hydrophobic to superhydrophilic. CONCLUSIONS:This study indicates that UV light pretreatment enhances the osteoconductive capacity of zirconia-based materials. 10.3390/ma9120958
    Fractured zirconia implants and related implant designs: scanning electron microscopy analysis. Osman Reham B,Ma Sunyoung,Duncan Warwick,De Silva Rohana K,Siddiqi Allauddin,Swain Michael V Clinical oral implants research OBJECTIVES:Two fractured one-piece experimental (commercially unavailable) zirconia implants were analyzed using scanning electron microscope (SEM) analysis to identify failure origins and aid in understanding the failure mechanisms. Modifications to the zirconia implant design are suggested to minimize such fracture incidences. MATERIALS AND METHODS:Two zirconia implants fractured during the final torquing in the maxillary ridge using the prescribed hand torque wrench. The implants were subsequently retrieved and prepared for optical and SEM evaluation. Critical attention was given to the fractography (crack morphology) of the fractured implants to identify the fracture origin. RESULTS:Events related to initiation and propagation of the crack front could be detected from the morphology of the fractured surfaces. Unfavorable torque and bending forces applied on the implant during surgical placement and the inherent flaws in the material may have resulted in crack initiation and implant failure. CONCLUSIONS:Caution must be exercised when placing zirconia implants in dense bone sites. Modification of surgical protocols for the intended implant site may be necessary. Improvement in design features specific to zirconia implants, and strict quality control during manufacture is essential to minimize the likelihood of fracture. 10.1111/j.1600-0501.2011.02411.x
    Essential oils and zirconia dental implant materials. Al-Radha Afya Sahib Diab,Younes Charles,Diab Ban Sahib,Jenkinson Howard F The International journal of oral & maxillofacial implants PURPOSE:This study was conducted to evaluate the effectiveness of natural antimicrobial agents in reducing biofilm development on different titanium and zirconia dental implant materials in vitro using a constant depth film fermentor (CDFF). MATERIALS AND METHODS:Contact angles and surface free energy were determined for all surfaces. Biofilms were grown on disks of polished partially stabilized zirconia, titanium blasted with zirconia, titanium blasted with zirconia and acid-etched, and polished titanium using a CDFF to simulate oral cavity conditions. Antimicrobials (cinnamon oil, clove oil, chlorhexidine gluconate, or 0.5% Tween 80) were pulsed twice daily to the biofilm to mimic application in the oral cavity. Samples were taken after 6, 24, and 48 hours. Serial dilutions were made and plated onto agar. Bacterial colonies were counted to determine colony-forming units/mL. RESULTS:Treatment of different implant material surfaces with the various antimicrobial agents led to significant increases in wettability and free energy on all surfaces. All surfaces showed a remarkable decrease in bacterial adhesion in the first 2 days in a relatively similar manner, with significant reduction in most of them, particularly after 48 hours. CONCLUSIONS:Functionalization of different dental implant material surfaces with essential oils resulted in immediate and ongoing antibacterial and antiplaque activities, and this antibacterial effect was enhanced with increased plaque age. Differences in the type of material seemed to have little effect on bacterial adhesion after treatment with antimicrobial agents. Expansion of this work with in vivo studies and clinical trials would be valuable. 10.11607/jomi.3142
    Zirconia with laser-modified microgrooved surface vs. titanium implants covered with melatonin stimulates bone formation. Experimental study in tibia rabbits. Calvo-Guirado José Luis,Aguilar Salvatierra Antonio,Gargallo-Albiol Jordi,Delgado-Ruiz Rafael Arcesio,Maté Sanchez Jose Eduardo,Satorres-Nieto Marta Clinical oral implants research OBJECTIVES:The aim of the study was to evaluate if zirconia implants with micro-grooved surfaces supplemented with melatonin enhance the bone-to-implant contact (BIC) vs. titanium implants with the same coating. MATERIALS AND METHODS:Eighty implants divided in four groups were inserted in the tibia of 20 New Zealand rabbits as follows: (group A) 20 titanium implants; (group B) 20 micro-grooved zirconia implants; (group C) 20 titanium implants supplemented with melatonin and (group D) 20 micro-grooved zirconia implants supplemented with melatonin. Histometric and SEM evaluation of BIC were evaluated after 1 and 4 weeks. RESULTS:At 1 week, group C (29.7 ± 2.4%) and group D (28.9 ± 1.3%) implants showed higher BIC% compared with group A and B (P < 0.05). After 4 weeks, group D showed higher BIC compared with all the groups (47.5 ± 2.2%) (P < 0.05). Also Connective tissue was higher in groups B (78.9 ± 2.1%) and D (88.7 ± 1.2%) related to titanium and zirconia melatonin untreated at 4 weeks (P < 0.05). CONCLUSIONS:Within the limitations of this pilot study in rabbits, we can conclude that the local application of melatonin increases the BIC values in titanium and in zirconia implants at 1 week. 10.1111/clr.12472
    Surface Modification Techniques for Zirconia-Based Bioceramics: A Review. Karthigeyan Suma,Ravindran Arun Jaikumar,Bhat Ramesh T R,Nageshwarao Madhulika Naidu,Murugesan Sree Varun,Angamuthu Vignesswary Journal of pharmacy & bioallied sciences Zirconia is gaining interest as a ceramic biomaterial for implant applications due to its biocompatibility and desirable mechanical properties. At present, zirconia-based bioceramics is often seen in the applications of hip replacement and dental implants. This article briefly reviews different surface modification techniques that have been applied to zirconia such as polishing, sandblasting, acid etching, biofunctionalization, coating, laser treatment, and ultraviolet light treatment. The potential of surface modification to make zirconia a successful implant material in the future is highly dependent on the establishment of successful and studies. Hence, further effort should be made in order to deepen the understanding of tissue response to implant and tissue regeneration process. 10.4103/JPBS.JPBS_45_19
    Effect of airborne-particle abrasion of presintered zirconia on surface roughness and bacterial adhesion. Zhang Ming,Zhang Zutai,Ding Ning,Zheng Dongxiang The Journal of prosthetic dentistry STATEMENT OF PROBLEM:Factors associated with implant periodontal disease of zirconia restorations such as surface roughness remain largely unknown. PURPOSE:The purpose of this study was to investigate how airborne-particle abrasion before sintering affects roughness and bacterial adhesion on the surface of zirconia. MATERIAL AND METHODS:Thirty presintered zirconia specimens were divided into 6 groups of 5 after being polished with silicon carbide paper (1200 grit). A different surface treatment was applied to each group (no treatment [group Ct] and 120-μm alumina abrasion for 5, 8, 10, 12, and 15 seconds [A5s, A8s, A10s, A12s, and A15s]), and the specimens were then densely sintered. The mean centric linear roughness (Ra) was measured, and the 3D measurement of surface roughness (3D roughness) was determined. The number of colony forming units (CFUs) of Streptococcus mutans adhering to the surface was also examined. One-way ANOVA was used for data analysis (α=.05). RESULTS:Airborne-particle abrasion before sintering significantly increased surface roughness. Group A8s, A10s, A12s, and A15s showed statistically significant higher CFU/mL than did group A5s (P<.05). No difference was found in CFU/mL between group Ct and A5s (P=.230). CONCLUSIONS:Airborne-particle abrasion before sintering is a useful method of increasing the surface roughness of zirconia. Ra < 0.58 μm is necessary to inhibit the adherence of S. mutans to zirconia. 10.1016/j.prosdent.2014.12.012
    Effect of Surface Modification on Viability of L929 Cells on Zirconia Nanocomposite Substrat. Aivazi Moluk,Fathi Mohammadhossein,Nejatidanesh Farahnaz,Mortazavi Vajihesadat,Hashemi Beni Batoul,Matinlinna Jukka Pekka Journal of lasers in medical sciences Zirconia bioceramic can be considered for metallic replacement in dental implant applications. A proper method of surface modification may promote better osseointegration. In study evaluated viability of fibroblast cell following surface treatment. Therefore, viability L929 cells were characterized using MTT assay and scanning electron microscopy. The viability assessment determined significant differences A-Y-TZP20 without surface treatment as compared to laser surface treatment (B), laser surface treatment + hydroxyapatiteyttrium stabilized tetragonal zirconia nanocomposite coat (C) and control. This study demonstrated that L929 cells approximately proliferated and spread on A-Y-TZP20 nanocomposite disk in laser surface treatment(B), Laser surface treatment + hydroxiapatite-yttrium stabilized tetragonal zirconia nanocomposite coat (C) groups similar to control group. Laser surface treatment showed positive effect on the viability of L929 cells. 10.15171/jlms.2018.18
    Evaluation of alumina toughened zirconia implants with a sintered, moderately rough surface: An experiment in the rat. Kohal Ralf J,Bächle Maria,Renz Alexander,Butz Frank Dental materials : official publication of the Academy of Dental Materials OBJECTIVE:Alumina toughened zirconia (ATZ) is more fracture resistant than unmodified zirconia and has been shown to be a viable substrate for the growth of osteoblasts. In this study, we examined the histological and biomechanical behavior of moderately roughened ATZ implants in rat femoral bone. METHODS:Miniature implants made of ATZ with pore-building polymers sintered onto the surface and electrochemically anodized titanium (TiUnite®) were placed into the femurs of Sprague-Dawley rats. Implant surface topography was analyzed by 3D laserscan measurements and scanning electron microscopy (SEM). After a healing period of 14 and 28 days, respectively, histologic and biomechanical testing was performed. RESULTS:Under the SEM, the TiUnite® surface could be clearly distinguished from the ATZ surface, but 3D laserscan measurements indicated a moderately rough surface topography for both, TiUnite® (Sa=1.31μm) and ATZ (Sa=1.51μm). The mean mineralized bone-to-implant contact showed the highest values after 14 and 28 days for TiUnite® (58%/75%) as compared to ATZ (24%/41%). The push-in values after a healing period of 14 and 28 days, respectively, increased from 20N to 39N for TiUnite® and from 10N to 25N for ATZ. SIGNIFICANCE:Our findings suggest that the moderately roughened ATZ implant surface is well accepted by rat bone tissue. However, compared to titanium, the osseointegration-process of ATZ seems to proceed more slowly in that early phase of implant integration. 10.1016/j.dental.2015.10.008
    Biological and osseointegration capabilities of hierarchically (meso-/micro-/nano-scale) roughened zirconia. Rezaei Naser Mohammadzadeh,Hasegawa Masakazu,Ishijima Manabu,Nakhaei Kourosh,Okubo Takahisa,Taniyama Takashi,Ghassemi Amirreza,Tahsili Tania,Park Wonhee,Hirota Makoto,Ogawa Takahiro International journal of nanomedicine Purpose:Zirconia is a potential alternative to titanium for dental and orthopedic implants. Here we report the biological and bone integration capabilities of a new zirconia surface with distinct morphology at the meso-, micro-, and nano-scales. Methods:Machine-smooth and roughened zirconia disks were prepared from yttria-stabilized tetragonal zirconia polycrystal (Y-TZP), with rough zirconia created by solid-state laser sculpting. Morphology of the surfaces was analyzed by three-dimensional imaging and profiling. Rat femur-derived bone marrow cells were cultured on zirconia disks. Zirconia implants were placed in rat femurs and the strength of osseointegration was evaluated by biomechanical push-in test. Results:The rough zirconia surface was characterized by meso-scale (50 µm wide, 6-8 µm deep) grooves, micro-scale (1-10 µm wide, 0.1-3 µm deep) valleys, and nano-scale (10-400 nm wide, 10-300 nm high) nodules, whereas the machined surface was flat and uniform. The average roughness (Ra) of rough zirconia was five times greater than that of machined zirconia. The expression of bone-related genes such as collagen I, osteopontin, osteocalcin, and BMP-2 was 7-25 times upregulated in osteoblasts on rough zirconia at the early stage of culture. The number of attached cells and rate of proliferation were similar between machined and rough zirconia. The strength of osseointegration for rough zirconia was twice that of machined zirconia at weeks two and four of healing, with evidence of mineralized tissue persisting around rough zirconia implants as visualized by electron microscopy and elemental analysis. Conclusion:This unique meso-/micro-/nano-scale rough zirconia showed a remarkable increase in osseointegration compared to machine-smooth zirconia associated with accelerated differentiation of osteoblasts. Cell attachment and proliferation were not compromised on rough zirconia unlike on rough titanium. This is the first report introducing a rough zirconia surface with distinct hierarchical morphology and providing an effective strategy to improve and develop zirconia implants. 10.2147/IJN.S159955
    Photofunctionalization of dental zirconia oxide: Surface modification to improve bio-integration preserving crystal stability. Roy Marco,Pompella Alfonso,Kubacki Jerzy,Piosik Adam,Psiuk Bronisław,Klimontko Joanna,Szade Jacek,Roy Robert A,Hedzelek Wieslaw Colloids and surfaces. B, Biointerfaces The use of zirconium oxide in dental implantology is rapidly increasing as it is regarded as being more aesthetical and biologically friendly than titanium oxide. The interaction of titanium oxide with cells and proteins has proven to be significantly affected by the inevitable atmospheric hydrocarbon contamination, defined as biological ageing. The latter has proven to be effectively reversed by UVC irradiation. Crystal structures of both Zr and Ti oxides are very similar, thus also ZrO is prone to contamination by hydrocarbons. In the present study we have characterized the chemical-physical changes occurring to ZrO after UVC irradiation. Firstly a reduction by 3-fold of carbon present on its surface. XRD analysis has indicated that UVC irradiation treatment does not affect the crystalline structure of ZrO, suggesting that it is possible to improve cell attachment on the surface without sacrificing the mechanical strength of the material. In addition a chemical model of interaction of cell surface proteins with the almost carbon free ZrO surface obtainable after UVC irradiation is proposed, pointing to the important role likely played by integrins and RGD sequences originating in soluble proteins adsorbed at the cell/ZrO interface. Hence in clinical practice UVC photofunctionalization could improve the soft tissue seal around dental implants functioning as a valid barrier between implant and peri-implant bone, thereby improving the long-term success of implants. 10.1016/j.colsurfb.2017.05.031
    Direct silanization of zirconia for increased biointegration. Caravaca Carlos,Shi Liu,Balvay Sandra,Rivory Pascaline,Laurenceau Emmanuelle,Chevolot Yann,Hartmann Daniel,Gremillard Laurent,Chevalier Jérôme Acta biomaterialia High-performance bioinert ceramics such as zirconia have been used for biomedical devices since the early seventies. In order to promote osseointegration, the historical solution has been to increase the specific surface of the implant through roughness. Nevertheless these treatments on ceramics may create defects at the surface, exposing the material to higher chances of early failure. In zirconia, such treatments may also affect the stability of the surface. More recently, the interest of improving osseointegration of implants has moved the research focus towards the actual chemistry of the surface. Inspired by this, we have adapted the current knowledge and techniques of silica functionalization and applied it to successfully introduce 3-aminopropyldimethylethoxy silane (APDMES) directly on the surface of zirconia (3Y-TZP). We used plasma of oxygen to clean the surface and promote hydroxylation of the surface to increase silane density. The samples were extensively characterized by means of X-ray photoelectron spectroscopy (XPS) and contact angle, mechanically tested and its cytotoxicity was evaluated through cell adhesion and proliferation tests. Additionally, aging was studied to discard negative effects of the treatment on the stability of the tetragonal phase. No adverse effect was found on the mechanical response of treated samples. In addition, plasma-treated samples exhibited an unexpectedly higher resistance to aging. Finally, silane density was 35% lower than the one reported in literature for silica. However cells displayed a qualitatively higher spreading in opposition to the rounder appearance of cells on untreated zirconia. These results lay the foundations for the next generation of zirconia implants with biologically friendlier surfaces. STATEMENT OF SIGNIFICANCE:The use of zirconia-based ceramics in biomedical devices is broad and well accepted, especially in dental implants. However, they do not bond naturally to bone, therefore to ensure fixation surgeons typically rely on roughness at different scales, or on cements. Alternatively in this work we present a new perspective of surface modification through chemistry to enhance the interaction between surface and biological environment, without the downsides of roughness. This surface treatment is proposed for zirconia, which allowed a direct silanization of its surface and a higher cell attachment. The results of this research may open the possibility for the next generation of bioinert ceramic implants with more advanced tailored surfaces for increased osseointegration. 10.1016/j.actbio.2016.09.034
    Effect of wet storage on the bioactivity of ultraviolet light- and non-thermal atmospheric pressure plasma-treated titanium and zirconia implant surfaces. Choi Sung-Hwan,Ryu Jeong-Hyun,Kwon Jae-Sung,Kim Jong-Eun,Cha Jung-Yul,Lee Kee-Joon,Yu Hyung-Seog,Choi Eun-Ha,Kim Kwang-Mahn,Hwang Chung-Ju Materials science & engineering. C, Materials for biological applications The aim of this study was to evaluate whether combining two treatments to avoid biological aging of the surface of titanium and zirconia implants; i.e., storage in an aqueous solution after ultraviolet light (UV) or non-thermal atmospheric pressure plasma (NTP) treatment, yielded surface bioactivity comparable to that following post-15-min UV or NTP treatment storage under air or immediately after UV or NTP treatment. Grade IV titanium discs modified by large grit sand-blasting and acid-etching (SLA) and smooth zirconia discs were irradiated with UV or NTP and their surface properties were evaluated immediately and after storage for 8 weeks in distilled HO (dHO) and a sealed container under air. Approximately 15-30 nm-sized nano-protrusions were formed only on SLA surfaces in dHO immediately after UV or NTP treatment. Immediate dHO storage after UV or NTP treatment prevented hydrocarbon contamination and maintained elevated amounts of Ti and Zr. After 8 weeks, unlike zirconia, protein adsorption, cellular adhesion, and cytoskeletal development of MC3T3-E1 cells on SLA surfaces stored in dHO immediately after UV treatment were further exceeding those immediately after UV or NTP treatments. UV treatment of SLA implants followed by wet storage can not only maintain but also strengthen bioactivity during shelf storage. 10.1016/j.msec.2019.110049
    Antimicrobial efficacy of photodynamic therapy and light-activated disinfection on contaminated zirconia implants: An in vitro study. Azizi Bleron,Budimir Ana,Bago Ivona,Mehmeti Blerim,Jakovljević Suzana,Kelmendi Jeta,Stanko Aleksandra Presecki,Gabrić Dragana Photodiagnosis and photodynamic therapy BACKGROUND:We aimed to evaluate the antimicrobial efficacy of photodynamic therapy (PDT) and light-activated disinfection (LAD) on zirconia dental implants contaminated with three bacterial species and investigate if the PDT and LAD cause implant surface alterations. METHODS:Seventy-two zirconia dental implants were contaminated with a bacterial suspension of Prevotella intermedia, Actinomyces actinomycetemcomitans, and Porphyromonas gingivalis. The implants were subsequently randomly divided into four groups (n = 12 dental implants/each) according to the decontamination protocol: Group 1 (PDT1) - PDT (660 nm, 100 mW) with toluidine blue; Group 2 (PDT2) - PDT (660 nm, 100 mW) with phenothiazine chloride dye; Group 3 (LAD) - light emitting diode (LED) with toluidine blue; and Group 4 (TB) - toluidine blue without the application of light. Implants in the positive control (PC) group were treated with a 0.2% chlorhexidine-based solution, and implants assigned to the negative control (NC) group did not undergo any treatment. Each implant was then placed in tubes containing phosphate buffered saline (PBS) and vortexed for 60 s to remove the remaining bacteria from the implant surface. After 10-fold serial dilutions, 30 μl of the suspension was plated on Brucella agar plates. After 72 h, the colony forming units (CFU) were counted. Distinctive colonies were confirmed with MALDI Biotyper. The implants were analyzed using scanning electron microscope (SEM) to evaluate the possible surface alterations due to PDT or LAD. RESULTS:All study groups had significant reductions in the number of CFUs compared with the NC (p < 0.05). PDT1, the PDT2, and the LAD groups had the largest bacterial reduction with respect to each bacterial species separately and the total bacterial count, and they were more efficient compared with the TB group (p < 0.05). SEM analysis did not reveal any alterations of the implant surface after the treatment procedures. CONCLUSION:Both PDT protocols and LAD showed high and equal effectiveness in decontamination of zirconia dental implants. 10.1016/j.pdpdt.2018.01.017
    Surface micro-structuring of zirconia dental implants. Fischer J,Schott A,Märtin S Clinical oral implants research OBJECTIVE:Sandblasting with subsequent acid etching is a potential procedure to generate microstructured surfaces on zirconia implants. The aim of the study was to systematically analyze the effect of these process steps on surface morphology and mechanical strength of the implants. MATERIALS AND METHODS:Zirconia implant blanks (ceramic.implant, VITA) were sandblasted (105-μm alumina, 6 bar), subsequently HF-etched, and finally heat-treated at 1250°C. Surface topographies were documented by SEM. Surface roughness Ra (n = 4), monoclinic volume fraction in the surface layer (n = 1), and static fracture load (n = 4) were measured. RESULTS:Surface roughness Ra reached a maximum of 1.2 μm after 4× sandblasting. Scratches and sharp edges dominated the surface aspect. Fracture load increased with the number of sandblasting cycles with a gain of 30% after 20 cycles. HF etching did not change the Ra values, but sharp edges were rounded and small pits created. A minor decrease in fracture load with increasing etching time was observed. Heat treatment of 1 h reduced the fracture load by 1/3. Longer heat treatment had no further effect. The roughness Ra was not modified by heat treatment. Fracture load was strongly correlated with the monoclinic fraction except for the results obtained directly after acid etching, where a constant monoclinic fraction was observed. CONCLUSIONS:Sandblasting with 105-μm alumina followed by 1 h HF etching at room temperature and 1 h heat treatment at 1250°C is a reliable and tolerant process to create a surface roughness of about Ra  = 1.2 μm on zirconia implants. 10.1111/clr.12553
    Cell Attachment Following Instrumentation with Titanium and Plastic Instruments, Diode Laser, and Titanium Brush on Titanium, Titanium-Zirconium, and Zirconia Surfaces. Lang Melissa S,Cerutis D Roselyn,Miyamoto Takanari,Nunn Martha E The International journal of oral & maxillofacial implants PURPOSE:The aim of this study was to evaluate the surface characteristics and gingival fibroblast adhesion of disks composed of implant and abutment materials following brief and repeated instrumentation with instruments commonly used in procedures for implant maintenance, stage-two implant surgery, and periimplantitis treatment. MATERIALS AND METHODS:One hundred twenty disks (40 titanium, 40 titaniumzirconium, 40 zirconia) were grouped into treatment categories of instrumentation by plastic curette, titanium curette, diode microlaser, rotary titanium brush, and no treatment. Twenty strokes were applied to half of the disks in the plastic and titanium curette treatment categories, while half of the disks received 100 strokes each to simulate implant maintenance occurring on a repetitive basis. Following analysis of the disks by optical laser profilometry, disks were cultured with human gingival fibroblasts. Cell counts were conducted from scanning electron microscopy (SEM) images. RESULTS:Differences in surface roughness across all instruments tested for zirconia disks were negligible, while both titanium disks and titaniumzirconium disks showed large differences in surface roughness across the spectrum of instruments tested. The rotary titanium brush and the titanium curette yielded the greatest overall mean surface roughness, while the plastic curette yielded the lowest mean surface roughness. The greatest mean cell counts for each disk type were as follows: titanium disks with plastic curettes, titanium-zirconium disks with titanium curettes, and zirconia disks with the diode microlaser. CONCLUSION:Repeated instrumentation did not result in cumulative changes in surface roughness of implant materials made of titanium, titanium-zirconium, or zirconia. Instrumentation with plastic implant curettes on titanium and zirconia surfaces appeared to be more favorable than titanium implant curettes in terms of gingival fibroblast attachment on these surfaces. 10.11607/jomi.4440
    Epithelial sealing effectiveness against titanium or zirconia implants surface. Atsuta Ikiru,Ayukawa Yasunori,Furuhashi Akihiro,Narimatsu Ikue,Kondo Ryosuke,Oshiro Wakana,Koyano Kiyoshi Journal of biomedical materials research. Part A The aims of implant treatment now involve not only restoration of mastication function, but also recovery of esthetics. Currently, zirconia is widely used as an esthetic material for implant abutment. Therefore, it is very important to understand the efficacy of zirconia for epithelial sealing as an implant material. We compared the effects of materials on the sealing of the peri-implant epithelium (PIE) to titanium (Ti) or zirconia (Zr) implants, for application to clinical work. Maxillary first molars were extracted from rats and replaced with Ti or Zr implants. The sealing of the PIE to the implants was evaluated with immunohistochemistry observation and HRP analysis. The morphological and functional changes in rat oral epithelial cells (OECs) cultured on Ti or Zr plates were also evaluated. After 4 weeks, the PIE on the Ti and Zr implants showed similar structures. The Zr implants appeared to form a weak epithelial seal at the tissue-implant interface, and exhibited markedly less adhesive structures than the Ti implants under electron microscopic observation. In the in vitro experiments, decreased expression levels of adhesion proteins were observed in OECs cultured on Zr plates compared with those cultured on Ti plates. In addition, the cell adherence on Zr plates was reduced, while the cell migration was low on Ti plates. Zr is a better choice for an esthetic implant material, but needs further improvement for integration with the epithelial wound healing process around a dental implant. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2019. 10.1002/jbm.a.36651
    Initial Bacterial Adhesion on Different Yttria-Stabilized Tetragonal Zirconia Implant Surfaces . Karygianni Lamprini,Jähnig Andrea,Schienle Stefanie,Bernsmann Falk,Adolfsson Erik,Kohal Ralf J,Chevalier Jérôme,Hellwig Elmar,Al-Ahmad Ali Materials (Basel, Switzerland) Bacterial adhesion to implant biomaterials constitutes a virulence factor leading to biofilm formation, infection and treatment failure. The aim of this study was to examine the initial bacterial adhesion on different implant materials . Four implant biomaterials were incubated with , and for 2 h: 3 mol % yttria-stabilized tetragonal zirconia polycrystal surface (B1a), B1a with zirconium oxide (ZrO₂) coating (B2a), B1a with zirconia-based composite coating (B1b) and B1a with zirconia-based composite and ZrO₂ coatings (B2b). Bovine enamel slabs (BES) served as control. The adherent microorganisms were quantified and visualized using scanning electron microscopy (SEM); DAPI and live/dead staining. The lowest bacterial count of was detected on BES and the highest on B1a. The fewest vital strains (42.22%) were detected on B2a surfaces, while most and strains (approximately 80%) were vital overall. Compared to BES; coated and uncoated zirconia substrata exhibited no anti-adhesive properties. Further improvement of the material surface characteristics is essential. 10.3390/ma6125659
    Surface roughened zirconia: towards hydrothermal stability. Camposilvan Erik,Flamant Quentin,Anglada Marc Journal of the mechanical behavior of biomedical materials Surface roughness is needed in several yttria-stabilized zirconia components used in restorative dentistry for osseointegration or adhesion purposes. This can be achieved by different treatments, which may also modify the microstructure of the surface. Among them, sandblasting and chemical etching are widely used, but their effect on hydrothermal aging of zirconia is not fully understood. In the present work, the zirconia long-term stability of rough surfaces prepared by these techniques is analyzed and a method is proposed for preventing hydrothermal aging while maintaining the original surface appearance and mechanical properties. The method involves pressure infiltration of a Cerium salt solution on the roughened surfaces followed by a thermal treatment. The solution, trapped by surface defects and small pores, is decomposed during thermal treatment into Cerium oxide, which is diffused at high temperature, obtaining Ce co-doping in the near-surface region. In addition, the microstructural changes induced in the near-surface by sandblasting or chemical etching are removed by the thermal treatment together with surface defects. No color modification was observed and the final roughness parameters were in the range of existing implants of proved good osseointegration. The aging resistance of Ce co-doped materials was strongly enhanced, showing the absence of aging after artificial degradation, increasing in this way the surface mechanical integrity. The proposed treatment is easily applicable to the current manufacturing procedures of zirconia dental posts, abutments, crowns and dentures, representing a solution to hydrothermal aging in these and other biomedical applications. 10.1016/j.jmbbm.2015.03.017
    [Effects of zirconia micron coating on the proliferation and differentiation of osteoblasts]. Wang Y F,Niu G L,Han J M Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology To investigate the effects of zirconia micro coating on the proliferation and differentiation of osteoblasts on the surface of zirconia ceramic, and to provide a strategy for zirconia implant surface treatment. Forty tablets of zirconia ceramic, with the diameter of 15 mm and the thickness of 1.5 mm, were prepared. Then, twenty tablets polished by water sandpaper were taken as the control group, and 20 pieces of the zirconia coating after sintering micron were taken as the experimental group. The micromorphology of the surface of the two groups were observed by scanning electron microscope. The cell morphology after inoculation with MC3T3-E1 of osteoblasts on the surface of the material was investigated for 1, 3, and 5 days by scanning electron microscope. The cell proliferation was detected at 1 and 3 days by methyl thiazolyl tetrazolium. The cell differentiation ability was detected at 3 and 7 days by real-time quantitative PCR. Statistical analysis was conducted by independent sample test. After coating with zirconia micron particles, pores with the diameter of 1-20 μm could be observed on the surface of the test group of tiles through high temperature sintering. The growth of osteoblasts on the surface of the ceramic chip in the test group and control group exhibited the similar cell morphology. As they were cultured for 1 day, the experimental group exhibited a similar quality of cells as those in the test group (>0.05). After 3 days incubation, comparing with the cell quality of the test group (1.067 ± 0.077) (<0.05), the quality of osteoblasts on the surface of zirconia ceramics coating increased to 1.763±0.165, and the expression of mRNA in alkaline phosphatase (ALP), osteopotin (OPN) and osteocalcin (OCN) also increased with the amount of 1.63±0.28, 1.99±0.41 and 1.60±0.30, respectively, compared with the test group (1.00± 0.00) (<0.05). Seven days later, the expression of mRNA in Runt-related transcription factor-2 (RNUX2) (1.33±0.19), special AT-rich sequence binding protein-2 (SATB2) (1.64 ± 0.36), as well as alkaline phosphatase (ALP) (1.78±0.40), OPN (2.25±0.36), and OCN (1.88±0.21), showed a remarkably increase compared with the test group (1.00±0.00) (<0.05). Zirconia micro coating on the surface of zirconia ceramics promoted the proliferation and differentiation of osteoblasts adhered. 10.3760/cma.j.issn.1002-0098.2018.05.010
    Prospective evaluation of zirconia based tooth- and implant-supported fixed dental prostheses: 3-year results. Konstantinidis Ioannis K,Jacoby Stephan,Rädel Michael,Böning Klaus Journal of dentistry OBJECTIVES:This prospective clinical study compared the performance of implant-retained (study group) and tooth-retained (control) zirconia based fixed dental prostheses (FDPs) with at least 4 units. The null-hypothesis stated that complication rates in both groups are equally distributed. METHODS:The study included patients in need of one 4- to 6-unit implant- or tooth-retained FDP each. All patients were examined 2 weeks after insertion (baseline) and then at 6 month intervals up to 3 years. At follow-up all restorations were examined for framework fracture, chipping, marginal integrity, surface roughness and biological complications. Kaplan-Meier estimation was used for data analysis. RESULTS:20 patients received tooth-retained and 7 patients implant-retained FDPs. The study was halted early when differences in chipping rates reached a statistically significant level. One FDP in the study group was lost due to implant abutment failure. FDP related chipping rates were 71% in the study group (mean observation time 32 months) and 15% in the control (mean observation time 34 months). Unit (abutment crown/pontic) related chipping rates were 32% in the study group and 6% in the control. Chipping rates differed statistically significant (log-rank test, p<.05). However, all ceramic defects could be corrected by grinding and polishing. No framework fracture was detected. CONCLUSIONS:Within the study limitations, survival rates seem satisfactorily in both implant- and tooth retained long-span zirconia based FDPs. However, implant-supported FDPs seem more susceptible to veneering ceramic chippings. CLINICAL SIGNIFICANCE:The high chipping rates found in this study discourage the use of long-span implant-retained FDPs with zirconia frameworks. The study was registered in ClinicalTrials.gov with the ID Number NCT02220764. 10.1016/j.jdent.2014.10.011
    Biomechanical and histological evaluation of the osseointegration capacity of two types of zirconia implant. Han Jian-Min,Hong Guang,Lin Hong,Shimizu Yoshinaka,Wu Yuhan,Zheng Gang,Zhang Hongyu,Sasaki Keiichi International journal of nanomedicine The purpose of this study was to evaluate the biomechanical and histological behavior of a ceria-stabilized zirconia-alumina nanocomposite (NanoZr) in comparison with that of 3 mol% yttria-stabilized tetragonal zirconia polycrystalline (3Y-TZP) in Sprague Dawley rats. Cylindrical NanoZr and 3Y-TZP implants (diameter 1 mm, length 2 mm) were used. Implant-surface morphology and surface roughness were determined by scanning white-light interferometry and scanning electron microscopy, respectively. The cylindrical zirconia implants were placed at the distal edge of the femur of Sprague Dawley rats. At weeks 2, 4, and 8, the interfacial shear strength between implant and bone was measured by push-in test. Histological analysis was performed using hard-tissue sections. Bone-implant contact (BIC), the thickness of new bone around the implant within the bone marrow area, and osteoclast numbers were evaluated. The average surface roughness of 3Y-TZP (Sa 0.788 μm) was significantly higher than that of NanoZr (Sa 0.559 μm). The shear strengths of 3Y-TZP and NanoZr were similar at 2 weeks, but at 4 and 8 weeks the shear strength of NanoZr was higher than that of 3Y-TZP. The average BIC values within the bone marrow area for 3Y-TZP and NanoZr were 25.26% and 31.51% at 2 weeks, 46.78% and 38% at 4 weeks, and 47.88% and 56.81% at 8 weeks, respectively. The average BIC values within the cortical area were 38.86% and 58.42% at 2 weeks, 66.82% and 57.74% at 4 weeks, and 79.91% and 78.97% at 8 weeks, respectively. The mean BIC value did not differ significantly between the two zirconia materials at any time point. The NanoZr implants were biocompatible, capable of establishing close BIC, and may be preferred for metal-free dental implants. 10.2147/IJN.S119519
    Bone response to functionally loaded, two-piece zirconia implants: A preclinical histometric study. Janner Simone F M,Gahlert Michael,Bosshardt Dieter D,Roehling Stefan,Milz Stefan,Higginbottom Frank,Buser Daniel,Cochran David L Clinical oral implants research OBJECTIVE:To evaluate the bone response to a two-piece zirconia implant in comparison with a control titanium implant in the canine mandible 4 and 16 weeks after restoration. MATERIAL AND METHODS:Zirconia and titanium implants were alternately placed bilaterally in healed mandibular molar and premolar sites of five canines. Full-ceramic single-tooth restorations were cemented after 6 weeks of transmucosal healing, allowing for full functional loading of the implants. Histologic and histometric analyses were performed on orofacial and mesiodistal undecalcified sections of the specimens obtained upon sacrifice after 4 and 16 weeks of functional loading. Bone-to-implant contact (BIC), multinucleated giant cells-to-implant contact (MIC), crestal bone level, and peri-implant bone density were histometrically assessed. RESULTS:All 60 implants and 60 restorations were still in function after 4 and 16 weeks of loading in both test and control groups. No implant loss, no implant or abutment fracture, and no chipping of the restorations could be detected. Histometric analysis showed no statistically significant differences between zirconia and titanium implants in BIC, crestal bone level, and peri-implant bone density at both time points. Between 4 and 16 weeks, the crestal bone level around zirconia implants showed a small but statistically significant increase in its distance from the implant shoulder. MIC was very low on both implant types and both time points and decreased statistically significantly overtime. CONCLUSION:The present two-piece zirconia implant showed a similar bone integration compared to the titanium implant with similar surface morphology after 4 and 16 weeks of loading. 10.1111/clr.13112
    Effect of ultraviolet photofunctionalisation on the cell attractiveness of zirconia implant materials. Tuna T,Wein M,Altmann B,Steinberg T,Fischer J,Att W European cells & materials Ultraviolet (UV) light treatment of implant surfaces has been demonstrated to enhance their bioactivity significantly. This study examined the effect of UV treatment of different zirconia surfaces on the response of primary human alveolar bone-derived osteoblasts (PhABO). Disks of two zirconia-based materials with two different surface topographies (smooth, roughened) were exposed to UV light. Qualitative and quantitative assessment of PhABO on zirconia surfaces, by means of immunofluorescence, scanning electron microscopy and DNA quantification at 4 and 24 h revealed a higher number of initially attached osteoblasts on UV-treated surfaces. Cell area and perimeter were significantly larger on all UV-treated surfaces (p<0.05). The proliferation activity was significantly higher on both roughened UV-treated surfaces than on untreated samples at day 3 of culture (p<0.05). The expression levels of collagen I, osteopontin and osteocalcin at day 14 and alkaline phosphatase activity at day 7 and 14 of culture period were similar among UV-treated and untreated surfaces. Alizarin-Red-Staining at day 21 demonstrated significantly more mineralised nodules on UV-treated samples than on untreated samples. Contact angle measurements and X-ray photoelectron spectroscopy showed that UV light transformed zirconia surfaces from hydrophobic to (super-) hydrophilic (p<0.05) and significantly reduced the atomic percentage of surface carbon. The results showed that UV light pre-treatment of zirconia surfaces changes their physicochemical properties and improves their attractiveness against PhABO, primarily demonstrated by an augmented cell attachment and spreading. This may result in faster healing and better bone-to-implant contact of zirconia implants in vivo following such a pre-treatment. 10.22203/ecm.v029a07
    Different behavior of human gingival fibroblasts on surface modified zirconia: A comparison between ultraviolet (UV) light and plasma. Yang Yang,Zheng Miao,Liao Yu,Zhou Jianfeng,Li Heping,Tan Jianguo Dental materials journal This study was to evaluate whether UV light irradiation and He plasma treatment of zirconia disks enhances its biocompatibility with human gingival fibroblasts (HGFs), and to compare the difference of two methods. Zirconia disks were prepared and divided into three groups: UVC light treatment (Group UV), He plasma (Group P), and control group. The surface morphology, wettability were analyzed. The cultured HGFs' adhesive density, morphology, proliferation and collagen synthesis were measured. After UV light and plasma treatment, contact angles decreased. HGFs' adhesion and proliferation in Group P was the highest (p<0.05) at each time point. HGFs on Group P also released the highest level of Col-1 after 3 and 7 days. Our study demonstrated that plasma and UV light treatment on smooth zirconia improved the hydrophilic property of surface in different mechanism and He plasma had the better effect on cells adhesion, proliferation, and especially on collagen synthesis. 10.4012/dmj.2018-101
    Surrounding Tissue Response to Surface-Treated Zirconia Implants. Iinuma Yohei,Hirota Masatsugu,Hayakawa Tohru,Ohkubo Chikahiro Materials (Basel, Switzerland) Yttria-stabilized tetragonal zirconia polycrystals (Y-TZP), which are partially stabilized zirconia, have been used for fabricating dental implants. This study investigated the soft tissue attachment, the collagen fiber orientation to zirconia at different surface conditions, and the bone response using implantation experiments in animals. The zirconia implant surfaces were treated with ultraviolet irradiation (UV), a combination of large-grit sandblasting and hydrofluoric acid etching (blastedHF), and a combination of blastedHF and UV (blastedHF+UV). The surface treated with blastedHF and blastedHF+UV appeared rough and hydrophilic. The surface treated with blastedHF+UV appeared to be superhydrophilic. Subsequently, tapered cylindrical zirconia implants were placed in the alveolar sockets of the maxillary molars of rats. The bone-to-implant contact ratio of blastedHF and blastedHF+UV implants was significantly higher than that of the non-treated controls and UV-treated implants. The four different surface-treated zirconia implants demonstrated tight soft tissue attachments. Perpendicularly oriented collagen fibers towards zirconia implants were more prominent in blastedHF and blastedHF+UV implants compared to the controls and UV-treated implants. The area of the soft tissue attachment was the greatest with the perpendicularly oriented collagen fibers of blastedHF+UV-treated implants. In conclusion, blastedHF+UV treatment could be beneficial for ensuring greater soft-tissue attachment for zirconia implants. 10.3390/ma13010030
    The impact of surface alteration on epithelial tissue attachment after the mechanical cleaning of titanium or zirconia surface. Hu Jiangqi,Atsuta Ikiru,Ayukawa Yasunori,Zhou Xudiyang,Dwi Rakhmatia Yunia,Koyano Kiyoshi Journal of oral rehabilitation OBJECTIVE:Mechanical plaque removal may alter the surface morphology of the gingival penetration part of the implant. We applied an air-powered abrasive system (AP), titanium curette (TC), stainless curette (SC), ultrasound scaler (US), and titanium brush (TB) which are commonly used to remove plaque, to titanium or zirconia and the changes in surface morphology and the epithelial attach against substrata. MATERIALS AND METHODS:(a) The morphological changes of titanium and zirconia after mechanical cleaning were assessed by scanning electron microscopy and a roughness analyser. (b) Oral epithelial cells of rats were inoculated on the surface of the materials after mechanical cleaning, and the adherence of epithelial cells was observed. (c) The maxillary first molars were extracted from the rats and replaced by experimental titanium or zirconia implants. The length of the immunoreactive laminin-332 band was observed at the implant-peri-implant epithelium interface. RESULTS:(a) The surface roughness increased in experimental groups except the AP group. (b) Among the experimental groups, the AP group showed the highest number of attached cells. (c) The length of the immunoreactive laminin-332 band was longer in the control group than those in all five experimental groups. Among the experimental groups, the AP group showed the longest band. CONCLUSION:All mechanical cleaning methods increased the surface roughness of the materials except AP. AP did not cause distinct implant surface alterations. Surface alteration caused by mechanical cleaning may evoke inferior for epithelial attachment and reduce resistance against foreign infiltration. 10.1111/joor.12920
    Effect of various surface preparations on bond strength of a gingiva-colored indirect composite to zirconia framework for implant-supported prostheses. Komine Futoshi,Koizuka Mai,Fushiki Ryosuke,Iwasaki Taro,Kubochi Kei,Matsumura Hideo Dental materials journal To evaluate the effects of various surface preparations on shear bond strength of a gingiva-colored indirect composite material and zirconia framework. Zirconia disks were prepared with one of nine surface treatments: hydrofluoric acid etching (HF), heating at 1,000°C for 10 min (HT), wet-grinding with 600- and 1500-grit SiC paper (SiC 600 and 1500), alumina-blasting at 0.1, 0.2, 0.4 and 0.6 MPa (AB 0.1, 0.2, 0.4, and 0.6), and no treatment (NT). An indirect composite material was bonded to zirconia. Shear bond strengths were measured. Bond strength was significantly higher in AB 0.2, 0.4, and 0.6 groups than in other groups at 0 and 20,000 thermocycles. Post-thermocycling bond strength was lower in NT, HF, and HT groups than in other groups. Alumina-blasting with 0.2 MPa or higher yielded sufficient durable bond strength between gingiva-colored indirect composite and zirconia frameworks. Hydrofluoric acid etching and heat treatment did not achieve durable bond strengths. 10.4012/dmj.2014-360
    Distinct cell functions of osteoblasts on UV-functionalized titanium- and zirconia-based implant materials are modulated by surface topography. Altmann Brigitte,Kohal Ralf-Joachim,Steinberg Thorsten,Tomakidi Pascal,Bächle-Haas Maria,Wennerberg Ann,Att Wael Tissue engineering. Part C, Methods Though recent studies report decisive positive effects on cells, elicited by ultraviolet (UV)-induced bioactivation of biomaterial implant surfaces, they frequently employ cells other than of human origin or cells not representing oral implant targets. Therefore, the present study aims at exploring distinct cell functions of primary human alveolar bone osteoblasts (PHABO) in response to bioactivated microstructured titanium and zirconia implant surfaces with matched controls. UV-treatment significantly reduced surface carbon, while concomitantly increasing wettability. In case of titanium or zirconia biomaterial source of equal roughness, bioactivation did not significantly improve cell functions, including initial cell attachment, morphogenesis, proliferation, and gene expression of osteogenic biomarkers osteocalcin, alkaline phosphatase and collagen type I. However, cell functions discriminated surface roughness by either comparing titanium and zirconia or interindividual zirconia surfaces. While rough surfaces primarily favored primary adhesion, proliferation appeared improved on smooth surfaces, and gene expression seemed to be stronger modulated on the smoothest biomaterial. Our results show for the first time that bioactivation appears to be not the main causative for the observed modulation of the distinct cell functions analyzed in PHABO, but add to the body of evidence that they were more governed by surface architecture rather than by bioactivation. 10.1089/ten.TEC.2012.0695
    Long-term stability of an injection-molded zirconia bone-level implant: A testing protocol considering aging kinetics and dynamic fatigue. Spies Benedikt C,Maass Madeleine E,Adolfsson Erik,Sergo Valter,Kiemle Tobias,Berthold Christoph,Gurian Elisa,Fornasaro Stefano,Vach Kirstin,Kohal Ralf-Joachim Dental materials : official publication of the Academy of Dental Materials OBJECTIVE:Separately addressing the fatigue resistance (ISO 14801, evaluation of final product) and aging behavior (ISO 13356, standardized sample) of oral implants made from yttria-stabilized zirconia proved to be insufficient in verifying their long-term stability, since (1) implant processing is known to significantly influence transformation kinetics and (2) aging, up from a certain level, is liable to decrease fatigue resistance. Therefore, the aim of this investigation was to apply a new testing protocol considering environmental conditions adequately inducing aging during dynamic fatigue. METHODS:Zirconia implants were dynamically loaded (10 cycles), hydrothermally aged (85°, 60 days) or subjected to both treatments simultaneously. Subsequent, monoclinic intensity ratios (X) were obtained by locally resolved X-ray microdiffraction (μ-XRD). Transformation propagation was monitored at cross-sections by μ-Raman spectroscopy and scanning electron microscopy (SEM). Finally, implants were statically loaded to fracture. Linear regression models (fracture load) and mixed models (X) were used for statistical analyses. RESULTS:All treatments resulted in increased fracture load (p≤0.005), indicating the formation of transformation induced compressive stresses around surface defects during all treatment modalities. However, only hydrothermal and combinational treatment were found to increase X (p<0.001). No change in X was observed for solely dynamically loaded samples (p≥0.524). Depending on the variable observed, a monoclinic layer thickness of 1-2μm (SEM) or 6-8μm (Raman spectroscopy) was measured at surfaces exposed to water during treatments. SIGNIFICANCE:Hydrothermal aging was successfully induced during dynamic fatigue. Therefore, the presented setup might serve as reference protocol for ensuring pre-clinically long-term reliability of zirconia oral implants. 10.1016/j.dental.2017.06.002
    Surface Characteristics of Bioactive Glass-Infiltrated Zirconia with Different Hydrofluoric Acid Etching Conditions. Oh Gye-Jeong,Yoon Ji-Hye,Vu Van Thi,Ji Min-Kyung,Kim Ji-Hyun,Kim Ji-Won,Yim Eun-Kyung,Bae Jung-Chan,Park Chan,Yun Kwi-Dug,Lim Hyun-Pil,Park Sang-Won Journal of nanoscience and nanotechnology The purpose of this study was to examine the surface characteristics of bioactive glass-infiltrated zirconia specimens that underwent different hydrofluoric acid (HF) etching conditions. Specimens were classified into the following six groups: Zirconia, Zirliner, Porcelain, Bioactive glass A1, Bioactive glass A2, and Bioactive glass A3. Zirliner and porcelain were applied to fully sintered zirconia followed by heat treatment. Bioactive glass was infiltrated into presintered zirconia using a spin coating method followed by complete sintering. All the specimens were acid-etched with 10% or 20% HF, and surface roughness was measured using a profiler. The surface roughness of the zirconia group was not affected by the etching time or the concentration of the acid. The roughness of the three bioactive glass groups (A1, A2, and A3) was slightly increased up until 10 minutes of etching. After 1 hour of etching, the roughness was considerably increased. The infiltrated bioactive glass and acid etching did not affect the adhesion and proliferation of osteoblasts. This study confirmed that surface roughness was affected by the infiltration material, etching time, and acid concentration. For implant surfaces, it is expected that the use of etched bioactive glass-infiltrated zirconia with micro-topographies will be similar to that of machined or sand-blasted/acid-etched (SLA) titanium.
    Accelerated Osteogenic Differentiation and Bone Formation on Zirconia with Surface Grooves Created with Fiber Laser Irradiation. Taniguchi Yusuke,Kakura Kae,Yamamoto Katsuki,Kido Hirofumi,Yamazaki Jun Clinical implant dentistry and related research BACKGROUND:Modification of the surface topography of biomaterials is a critical factor for the proliferation and differentiation of osteoblasts. Elucidating the biological response to surface roughening is necessary for clinical application of zirconia implants. PURPOSE:To investigate the effects of fiber laser-induced zirconia surface roughening on cultured osteoblast-like cell morphology, proliferation, differentiation, and calcification, and on in vivo bone formation. MATERIALS AND METHODS:Sixty-six machine-surfaced yttria-tetragonal zirconia polycrystal plates (S-Zr) and 16 machine-surfaced implants were used as controls. We prepared 66 rough plates (R-Zr) and 16 rough implants by surface treatment using a fiber laser. RESULTS:MC3T3-E1 cells spread well in all directions on S-Zr, whereas elongated cells with poorly organized actin stress fibers were observed on R-Zr. Cell proliferation was significantly greater on R-Zr than on S-Zr. The Runx2 mRNA level increased time dependently in osteogenic culture condition. Alkaline phosphatase activity and osteocalcin mRNA levels were higher on R-Zr compared with S-Zr. Alizarin red S staining revealed greater calcification on R-Zr than on S-Zr. Laser treatment of zirconia implant bodies placed in rat tibiae increased the bone-implant contact ratio and removal torque considerably. CONCLUSIONS:Our results suggest that fiber laser irradiation produces adequate surface roughening of zirconia ceramics to support osseointegration. 10.1111/cid.12366
    Changes in surface characteristics of titanium and zirconia after surface treatment with ultraviolet light or non-thermal plasma. Henningsen Anders,Smeets Ralf,Heuberger Roman,Jung Ole T,Hanken Henning,Heiland Max,Cacaci Claudio,Precht Clarissa European journal of oral sciences Positive effects of irradiation with ultraviolet (UV) light or treatment with non-thermal plasma on titanium and zirconia surfaces have been described in various studies. The aim of this study was to assess and compare the changes in the physicochemical surface conditions of titanium and zirconia surfaces after a short treatment with UV light or with non-thermal plasmas of argon or oxygen. Titanium and zirconia samples with moderately rough surfaces were treated for 12 min either in a UV-light oven or in a non-thermal plasma reactor that generates non-thermal plasmas of oxygen or argon. Changes in surface conditions were assessed by confocal microscopy, dynamic contact angle measurement, and X-ray photoelectron spectroscopy (XPS). No changes in roughness occurred. Ultraviolet irradiation and non-thermal plasma significantly increased the wettability of the titanium and zirconia surfaces. X-ray photoelectron spectroscopy showed an increase of oxygen and a significant decrease of carbon after treatment with either method. Thus, ultraviolet light and non-thermal plasma were found to be able to improve the chemical surface conditions of titanium and zirconia following a short exposure time. However, further in vitro and in vivo studies are needed to determine the relevance of the results. 10.1111/eos.12400
    Mechanical anchorage and peri-implant bone formation of surface-modified zirconia in minipigs. Schliephake Henning,Hefti Thomas,Schlottig Falko,Gédet Philippe,Staedt Henning Journal of clinical periodontology AIM:To test the hypothesis that peri-implant bone formation and mechanical stability of surface-modified zirconia and titanium implants are equivalent. MATERIALS AND METHODS:Twelve minipigs received three types of implants on either side of the mandible 8 weeks after removal of all pre-molar teeth: (i) a zirconia implant with a sandblasted surface; (ii) a zirconia implants with a sandblasted and etched surface; and (iii) a titanium implant with a sandblasted and acid-etched surface that served as a control. Removal torque and peri-implant bone regeneration were evaluated in six animals each after 4 and 13 weeks. RESULTS:The titanium surface was significantly rougher than both tested zirconia surfaces. Mean bone to implant contact (BIC) did not differ significantly between the three implant types after 4 weeks but was significantly higher for titanium compared with both zirconia implants after 13 weeks (p<0.05). Bone volume density (BVD) did not differ significantly at any interval. Removal torque was significantly higher for titanium compared with both zirconia surfaces after 4 and 13 weeks (p<0.001). The sandblasted and etched zirconia surface showed a significantly higher removal torque after 4 weeks compared with sandblasted zirconia (p<0.05); this difference levelled out after 13 weeks. CONCLUSIONS:It is concluded that all implants achieved osseointegration with similar degrees of BIC and BVD; however, titanium implants showed a higher resistance to removal torque, probably due to higher surface roughness. 10.1111/j.1600-051X.2010.01549.x
    Evaluation of laser bacterial anti-fouling of transparent nanocrystalline yttria-stabilized-zirconia cranial implant. Damestani Yasaman,De Howitt Natalie,Halaney David L,Garay Javier E,Aguilar Guillermo Lasers in surgery and medicine BACKGROUND AND OBJECTIVE:The development and feasibility of a novel nanocrystalline yttria-stabilized-zirconia (nc-YSZ) cranial implant has been recently established. The purpose of what we now call "window to the brain (WttB)" implant (or platform), is to improve patient care by providing a technique for delivery and/or collection of light into/from the brain, on demand, over large areas, and on a chronically recurring basis without the need for repeated craniotomies. WttB holds the transformative potential for enhancing light-based diagnosis and treatment of a wide variety of brain pathologies including cerebral edema, traumatic brain injury, stroke, glioma, and neurodegenerative diseases. However, bacterial adhesion to the cranial implant is the leading factor for biofilm formation (fouling), infection, and treatment failure. Escherichia coli (E. coli), in particular, is the most common isolate in gram-negative bacillary meningitis after cranial surgery or trauma. The transparency of our WttB implant may provide a unique opportunity for non-invasive treatment of bacterial infection under the implant using medical lasers. STUDY DESIGN/MATERIALS AND METHODS:A drop of a diluted overnight culture of BL21-293 E. coli expressing luciferase was seeded between the nc-YSZ implant and the agar plate. This was followed by immediate irradiation with selected laser. After each laser treatment the nc-YSZ was removed, and cultures were incubated for 24 hours at 37 °C. The study examined continuous wave (CW) and pulsed wave (PW) modes of near-infrared (NIR) 810 nm laser wavelength with a power output ranging from 1 to 3 W. During irradiation, the temperature distribution of nc-YSZ surface was monitored using an infrared thermal camera. Relative luminescence unit (RLU) was used to evaluate the viability of bacteria after the NIR laser treatment. RESULTS:Analysis of RLU suggests that the viability of E. coli biofilm formation was reduced with NIR laser treatment when compared to the control group (P < 0.01) and loss of viability depends on both laser fluence and operation mode (CW or PW). The results demonstrate that while CW laser reduces the biofilm formation more than PW laser with the same power, the higher surface temperature of the implant generated by CW laser limits its medical efficacy. In contrast, with the right parameters, PW laser produces a more moderate photothermal effect which can be equally effective at controlling bacterial growth. CONCLUSIONS:Our results show that E. coli biofilm formation across the thickness of the nc-YSZ implant can be disrupted using NIR laser treatment. The results of this in vitro study suggest that using nc-YSZ as a cranial implant in vivo may also allow for locally selective, non-invasive, chronic treatment of bacterial layers (fouling) that might form under cranial implants, without causing adverse thermal damage to the underlying host tissue when appropriate laser parameters are used. Lasers Surg. Med. 48:782-789, 2016. © 2016 Wiley Periodicals, Inc. 10.1002/lsm.22558
    Effects of different surface treatments on the cyclic fatigue strength of one-piece CAD/CAM zirconia implants. Ding Qian,Zhang Lei,Bao Rui,Zheng Gang,Sun Yuchun,Xie Qiufei Journal of the mechanical behavior of biomedical materials OBJECTIVES:The effects of different surface treatments on cyclic fatigue strengths of computer-aided design and computer-aided manufacturing (CAD/CAM) zirconia implants and its mechanisms were evaluated. MATERIAL AND METHODS:One-piece cylindrical screw-type zirconia (Y-TZP) implants with diameters of 4.1-mm were fabricated using CAD/CAM technique; they were divided into four groups according to the type of surface treatment: (i) sintering (control group, CTRL), (ii) sandblasting (SB), (iii) sandblasting and etching with an experimental hot etching solution (SB-ST), and (iv) sandblasting and etching with hydrofluoric acid (SB-HF). The surface morphology and roughness of the implants were evaluated. Tetragonal to monoclinic transformation was measured on the surface by micro Raman spectroscopy. Static and fatigue tests were carried out at room temperature following the ISO 14801:2014 Standard. The cyclic fatigue strength of each group was determined using the staircase method. Specimens that survived the fatigue test were statically loaded to measure the residual fracture strength. RESULTS:Among the four groups, SB-HF exhibited the highest surface roughness. Compared with the CTRL group, the surface monoclinic content was higher after all three types of surface treatments, amongst which, SB-HF had the highest content (39.14%), significantly more than the other three groups (P < 0.01). The cyclic fatigue strengths of CTRL, SB, SB-ST, and SB-HF implants were 530 N, 662.5 N, 705 N, and 555 N, respectively. The fracture strength after fatigue loading was higher than that before fatigue loading with no significant difference (P>0.05). CONCLUSIONS:SB and SB-ST remarkably enhanced the fatigue resistance of zirconia implants, while SB-HF did not. One-piece 4.1-mm diameter CAD/CAM zirconia implants have sufficient durability for application in dental implants. 10.1016/j.jmbbm.2018.05.002
    Influence of a nanoporous zirconia implant surface of on cell viability of human osteoblasts. Aboushelib Moustafa N,Osman Essam,Jansen Ineke,Everts Vincent,Feilzer Albert J Journal of prosthodontics : official journal of the American College of Prosthodontists PURPOSE:The dense nonretentive surface of zirconia implants was modified into a nanoporous surface using selective infiltration etching surface treatment. The aim of this study was to investigate the influence of such a nanoporous modified zirconia surface on the attachment of human osteoblasts. MATERIALS AND METHODS:Human osteoblasts were cultured for 21 days on (i) selective infiltration etched zirconia (nanoporous surface), (ii) polished zirconia, (iii) polished titanium, or (iv) airborne particle abraded acid etched (SLA) titanium disks. After the culture period the following parameters were assessed: number of cells, the morphology of the cells, the attachment of the cells, alkaline phosphatase activity, and the level of total protein (α= 0.05). RESULTS:Statistical analysis revealed a significantly higher cell count on the third (F = 17.4, p < 0.001) and eighth day (F = 163, p < 0.001) for nanoporous zirconia and SLA titanium surfaces compared to polished specimens. The number of cells (nanoporous zirconia 160 ± 20/mm(2) , SLA titanium 133 ± 15/mm(2) ) and cell size (nanoporous zirconia 50.7 ± 3 μm, SLA titanium 42.5 ± 4 μm) were significantly higher than polished specimens. Nanoporous zirconia specimens demonstrated comparable alkaline phosphatase activity (0.0036 ± 0.0035 ng/μl) and intracellular protein content (72.7 ± 0.9 ng/μl) compared to other tested groups. Scanning electron microscopy revealed that cells attached on the polished surface using finger-like processes, whereas on the nanoporous surface, finger-like processes were not observed, as the cell membrane appeared to be in close proximity to the underlying surface. CONCLUSION:The findings of this study suggest that a nanoporous zirconia surface favors cell growth and attachment compared to a polished surface. It was proposed that a nanoporous zirconia surface may improve clinical performance of zirconia implants. 10.1111/j.1532-849X.2012.00920.x
    Peri-implant bone response to retrieved human zirconia oral implants after a 4-year loading period: A histologic and histomorphometric evaluation of 22 cases. Kohal Ralf-Joachim,Schwindling Franz Sebastian,Bächle Maria,Spies Benedikt Christopher Journal of biomedical materials research. Part B, Applied biomaterials AIM:To evaluate the bone tissue response to surface modified zirconia oral implants retrieved from humans. MATERIALS AND METHODS:Twenty-nine one-piece zirconia implants showed increased marginal bone loss and did not response to the applied peri-implantitis therapy. After their removal using a trephine bur, 22 of the implant-bone biopsies were suitable for an evaluation and immediately immersed in formalin for two weeks. Subsequent, the retrieved specimens were histologically prepared and the regions still showing osseointegration computer-assisted analyzed regarding the bone-to-implant contact (BIC) and bone density using a transmitted-light microscope. RESULTS:The removed implants were in situ for a mean time period of 47.7 months. After their removal, compact bone could be depicted at the apical regions. The remaining bone that was attached to the implants contained a regular lamellar structure with osteons and osteocytes. The BIC ranged from 58.1% to 93.7% (mean: 76.5%) and the bone area/density within the implant threads ranged from 57% to 97.2% (mean: 84.8%). CONCLUSIONS:The porous zirconia implants showed a sufficient BIC in the areas where bone still was attached. Although the implants had to be removed due to increased bone loss, it seems that the presented zirconia implant surface per se elicited appropriate osseointegration. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1622-1631, 2016. 10.1002/jbm.b.33512
    Peri-implant bone formation and surface characteristics of rough surface zirconia implants manufactured by powder injection molding technique in rabbit tibiae. Park Young-Seok,Chung Shin-Hye,Shon Won-Jun Clinical oral implants research OBJECTIVE:To evaluate osseointegration in rabbit tibiae and to investigate surface characteristics of novel zirconia implants made by powder injection molding (PIM) technique, using molds with and without roughened inner surfaces. MATERIAL AND METHODS:A total of 20 rabbits received three types of external hex implants with identical geometry on the tibiae: machined titanium implants, PIM zirconia implants without mold etching, and PIM zirconia implants with mold etching. Surface characteristics of the three types of implant were evaluated. Removal torque tests and histomorphometric analyses were performed. RESULTS:The roughness of PIM zirconia implants was higher than that of machined titanium implants. The PIM zirconia implants exhibited significantly higher bone-implant contact and removal torque values than the machined titanium implants (P < 0.001). The PIM zirconia implants using roughened mold showed significantly higher removal torque values than PIM zirconia implants without using roughened mold (P < 0.001). CONCLUSIONS:It is concluded that the osseointegration of PIM zirconia implant is promising and PIM using roughened mold etching technique can produce substantially rough surfaces on zirconia implants. 10.1111/j.1600-0501.2012.02468.x
    Peri-implant bone formations around (Ti,Zr)O(2) -coated zirconia implants with different surface roughness. Chung Shin Hye,Kim Hong-Kyun,Shon Won-Jun,Park Young-Seok Journal of clinical periodontology AIM:The aim of this study was to evaluate and compare the osseointegration in rabbit tibiae of smooth and roughened powder injection moulded (PIM) zirconia implants with or without (Ti,Zr)O2 surface coatings. MATERIAL AND METHODS:Twenty-five rabbits received four types of external hex implants with identical geometry on the tibiae: PIM zirconia implants, roughened PIM zirconia implants, (Ti,Zr)O2 -coated PIM zirconia implants and (Ti,Zr)O2 -coated roughened PIM zirconia implants. The surface characteristics of the four types of implants were evaluated. Removal torque tests and histomorphometric analyses were performed. RESULTS:The (Ti,Zr)O2 coatings substantially changed the surface topography and chemical composition of the both type of PIM zirconia implants. There were statistically significant differences in the bone to implant contact ratios and removal torque values (RT) among the tested implant types (p < 0.001). The histological response favoured the coated surface at smooth PIM zirconia implants. The removal torque values favoured the rough surface whether coated or uncoated. CONCLUSIONS:Within the limit of this study, the (Ti,Zr)O2 coated PIM zirconia implants, both smooth and rough, showed enhanced histological response (bone to implant contact) compared with uncoated ones. On the other hand, the mechanical anchorage (RT) was higher for rough surface implants, coated or uncoated. 10.1111/jcpe.12073
    Ultraviolet light-treated zirconia with different roughness affects function of human gingival fibroblasts in vitro: the potential surface modification developed from implant to abutment. Yang Yang,Zhou Jianfeng,Liu Xiaoqiang,Zheng Miao,Yang Jianjun,Tan Jianguo Journal of biomedical materials research. Part B, Applied biomaterials OBJECTIVES:To evaluate whether ultraviolet (UV) light irradiation of smooth and rough zirconia disks enhances its biocompatibility with human gingival fibroblasts (HGFs). MATERIALS AND METHODS:Zirconia disks were divided into four groups: smooth control (S-C), smooth with UV light treatment (S-UV), rough control (R-C), and rough with UV light treatment (R-UV). The surface morphology and wettability were analyzed, and X-ray photoelectron spectroscopy was carried out. The cultured HGFs' adhesive density, morphology, proliferation, and collagen synthesis were measured on different time points from 3 h to 7 days. RESULTS:After 24-h UV light treatment, contact angles decreased from 51.98° (S-C) and 63.87° (R-C) to 33.76° (S-UV) and 36.15° (R-UV). X-ray photoelectron spectroscopy analysis showed that surface C/O ratio reduced from 1.86 and 2.39 to 1.33 and 1.19. After UV light treatment, cells initial spreading areas and perimeters were doubled on S-UV disks and nearly tripled on R-UV disks. Three hours cell adhesion was enhanced on S-UV disks, and 24-h cell density was increased on R-UV. Cell proliferation of 48 or 72 h was all significantly changed on UV-treated disks. Cells on R-UV also released highest level of Col-1 after 3 and 7 days, whereas those on S-UV produced less levels compared with control. CONCLUSION:Our study demonstrated for the first time that UV light treatment on rough (Ra = 0.19 ± 0.03 μm) zirconia had a positive effect on behavior of HGFs, including 24-h cell adhesion, proliferation, and collagen release. The effect varied with surface roughness and time point. Surface morphology and hydrophilicity, as two interacted factors, both are governed on HGFs behavior. 10.1002/jbm.b.33183
    Cortical bone response toward nanosecond-pulsed laser-treated zirconia implant surfaces. Hirota Masatsugu,Harai Tomohiro,Ishibashi Shinji,Mizutani Masayoshi,Hayakawa Tohru Dental materials journal Two type of partially stabilized zirconia, namely yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and ceria-stabilized tetragonal zirconia polycrystals including aluminum oxide nanocomposite (Ce-TZP), were irradiated by nanosecond-pulsed Nd:YAG laser and the regular structure with concave and convex of each 30 μm width and 30 μm depth were prepared on both surfaces. In the case of Ce-TZP, the surface was changed to be black after laser irradiation. EDX measurement revealed the reduction of more amounts of oxygen atoms on Ce-TZP compared to Y-TZP. Laser irradiated zirconia implants were inserted into the bone defects of rat femur during 4 weeks. As a control, large grid sandblasted and acid etching (blastedHF) implant was used. Laser treatment for Y-TZP provided greater degree of bone-implant contact ratio than blastedHF treated Y-TZP (p<0.05). In the case of Ce-TZP, however, laser treatment showed no clear effect on bone response. 10.4012/dmj.2018-153
    Titanium implant with nanostructured zirconia surface promotes maturation of peri-implant bone in osseointegration. Dusad Anand,Chakkalakal Dennis A,Namavar Fereydoon,Haider Hani,Hanisch Brock,Duryee Michael J,Diaz April,Rensch Adam,Zhang Yijia,Hess Ryan,Thiele Geoffrey M,Fehringer Edward V Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine The goal of the experiment outlined in this article is to improve upon noncemented methods of arthroplasty for clinical application in elderly patients. This was done by determining whether titanium implants with a novel nanostructured zirconia surface, which was created by ion beam-assisted deposition, would prevent impaired osseointegration of intramedullary implants in 1-year-old rats receiving a protein-deficient diet. Specifically, we asked whether the implant with the nanostructured zirconia surface would increase expression of markers of bone maturation within the remodeling of peri-implant woven bone. The control implants, which were made of commercially pure titanium, had a polished surface ex vivo but are known to acquire a microstructured titania surface in vivo. Ten 1-year-old rats received experimental implant (group A) and 10 had control (group B) implants. Ten 3-month-old rats received normal protein diet and the control implant (group C). Animals were euthanized 8 weeks after implantation, and transverse sections of femur-implant samples were used for histology, micro-computed tomography and immunohistochemical evaluations. In group B, the expression of α2β1 and α5β1 integrins, which are known to mediate osteoblast adhesion, glycosaminoglycans, heparan sulfate and chondroitin sulfate, was less than half of that in group C. Important to this study, the zirconia surface used in group A prevented these deficiencies. Therefore, these results indicate that nanostructured zirconia surface created on clinical implants by ion beam-assisted deposition may prevent impaired osseointegration in elderly patients by promoting quicker maturation of peri-implant woven bone. 10.1177/0954411913479300
    Peri-implant bone formation of non-thermal atmospheric pressure plasma-treated zirconia implants with different surface roughness in rabbit tibiae. Shon Won-Jun,Chung Shin Hye,Kim Hong-Kyun,Han Geum-Jun,Cho Byeong-Hoon,Park Young-Seok Clinical oral implants research OBJECTIVES:The aim of this study was to evaluate and compare the osseointegration of powder-injection molded (PIM) zirconia implants in rabbit tibiae with or without He plasma treatment. MATERIAL AND METHODS:Twenty-five rabbits received 4 types of external hex implants with identical geometry in the tibiae: PIM zirconia implants, roughened PIM zirconia implants, plasma-treated PIM zirconia implants, and plasma-treated roughened PIM zirconia implants. The contact angles of the four types of implants were evaluated. Removal torque tests and histomorphometric analyses were performed. RESULTS:The plasma treatment markedly enhanced the hydrophilicity, but did not seem to change the surface topography of the PIM zirconia implants. There were statistically significant differences in the bone-to-implant contact (BIC) ratios, bone volume (BV/TV), and removal torque values (RTQ) among the tested implant types (P < 0.001). The plasma-treated implants exhibited significantly higher BIC and BV/TV values than the untreated implants. However, the removal torque values favored the rough surface. CONCLUSIONS:The He plasma treatments on PIM zirconia implants made the surface more hydrophilic and enhanced the osseointegration of the implants without changing the micro-topography. 10.1111/clr.12115
    Histological, radiological and histomorphometric evaluation of immediate vs. non-immediate loading of a zirconia implant with surface treatment in a dog model. Calvo-Guirado Jose L,Aguilar-Salvatierra Antonio,Gomez-Moreno Gerardo,Guardia Javier,Delgado-Ruiz Rafael A,Mate-Sanchez de Val Jose Eduardo Clinical oral implants research OBJECTIVE:The aim of this study was to assess the performance of zirconia implants under immediate loading compared with delayed loading in dogs over 30-90 days. MATERIALS AND METHODS:Tooth extractions were made for the subsequent placement of dental implants at premolars P2, P3, P4 and molars M1 bilaterally in the dog mandible. Forty eight zirconia implants, 4 mm in diameter and 10 mm in length, were inserted, whose neck and body surfaces had been treated with femtosecond laser texturing; 24 implants were loaded immediately and 24 remained unloaded during the osseointegration period. Final radiographs were taken recording stability values before sacrifice at 30 or 90 days when sample removal for histological and histomorphometric analysis was performed. Bone-to-implant contact, crestal bone loss and implant stability were evaluated at these two study times. RESULTS:Bone-to-implant contact values after 30 days were 38.9% for immediately loaded implants and 32% for non-loaded implants. After 90 days, values increased to 65% for immediately loaded and 57.6% for non-loaded implants. After 30 days, there was more crestal bone lost in the non-loaded group (0.58 ± 0.28 mm) compared with the immediately loaded group (0.5 ± 0.3 mm). After 90 days, there was improved stability in both groups, but was lower in the immediately loaded group (0.5 ± 0.23 mm) compared with the non-loaded group (0.56 ± 0.28 mm). Initial implant stability values were -3.5 PTV at the moment of implant placement. Stability values after the first 30 days were -4 for immediately loaded implants and -3 for non-loaded. At 90 days, non-loaded implants showed -4.9, whereas immediately loaded showed -7.1. CONCLUSIONS:For the different parameters studied, zirconia implants treated with femtosecond laser and subjected to immediate loading showed better results compared with non-loaded implants in terms of BIC, crestal bone loss and implant stability. 10.1111/clr.12145
    Is zirconia a viable alternative to titanium for oral implant? A critical review. Sivaraman Karthik,Chopra Aditi,Narayan Aparna I,Balakrishnan Dhanasekar Journal of prosthodontic research PURPOSE:Titanium based implant systems, though considered as the gold standard for rehabilitation of edentulous spaces, have been criticized for many inherent flaws. The onset of hypersensitivity reactions, biocompatibility issues, and an unaesthetic gray hue have raised demands for more aesthetic and tissue compatible material for implant fabrication. Zirconia is emerging as a promising alternative to conventional Titanium based implant systems for oral rehabilitation with superior biological, aesthetics, mechanical and optical properties. This review aims to critically analyze and review the credibility of Zirconia implants as an alternative to Titanium for prosthetic rehabilitation. STUDY SELECTION:The literature search for articles written in the English language in PubMed and Cochrane Library database from 1990 till December 2016. The following search terms were utilized for data search: "zirconia implants" NOT "abutment", "zirconia implants" AND "titanium implants" AND "osseointegration", "zirconia implants" AND compatibility. RESULTS:The number of potential relevant articles selected were 47. All the human in vivo clinical, in vitro, animals' studies were included and discussed under the following subheadings: Chemical composition, structure and phases; Physical and mechanical properties; Aesthetic and optical properties; Osseointegration and biocompatibility; Surface modifications; Peri-implant tissue compatibility, inflammation and soft tissue healing, and long-term prognosis. CONCLUSIONS:Zirconia implants are a promising alternative to titanium with a superior soft-tissue response, biocompatibility, and aesthetics with comparable osseointegration. However, further long-term longitudinal and comparative clinical trials are required to validate zirconia as a viable alternative to the titanium implant. 10.1016/j.jpor.2017.07.003
    Influence of ultraviolet photofunctionalization on the surface characteristics of zirconia-based dental implant materials. Tuna Taskin,Wein Martin,Swain Michael,Fischer Jens,Att Wael Dental materials : official publication of the Academy of Dental Materials OBJECTIVES:To examine the effect of ultraviolet light (UV) treatment on the surface characteristics of two acid-etched zirconia-based dental implant materials. METHODS:Discs of two zirconia-based materials (Zr1 and Zr2) with smooth (m) and roughened (r) surfaces were treated by UV light for 15min. The surface topography was investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The surface elemental composition of all samples was determined by X-ray photoelectron spectroscopy (XPS), the crystalline property by X-ray diffraction (XRD) and the hydrophilic status by contact angle (CA) measurements of a water droplet. RESULTS:SEM and AFM revealed quantitative and qualitative differences between the roughened and smooth surfaces. UV treatment did not induce any topographic changes of the tested surfaces (p>0.05). All UV-treated samples showed a significant surface elemental content change with a decrease of carbon by 43-81%, an increase of oxygen by 19-45%, and an increase of zirconia by 9-41%. Upon UV treatment, a 19-25% increase of the crystalline monoclinic phase was observed on surfaces of material Zr1, whereas a slight increase on the smooth Zr2 surface (+3%) and a decrease on the roughened Zr2 surface by 20% was observed. For all samples, the hydrophilic status changed significantly from hydrophobic to hydrophilic by UV treatment (p<0.0001). The average contact angles were between 56.4° and 69° before and 2.5° and 14.1° after UV-light treatment. SIGNIFICANCE:UV treatment altered the physicochemical properties of the two zirconia implant surfaces investigated. The mechanism by which such changes are induced requires further investigation. 10.1016/j.dental.2014.10.008
    Osseointegration of zirconia implants with 3 varying surface textures and a titanium implant: A histological and micro-CT study. Kubasiewicz-Ross Paweł,Hadzik Jakub,Dominiak Marzena Advances in clinical and experimental medicine : official organ Wroclaw Medical University BACKGROUND:Zirconium - a bioinert metal - in comparison with titanium implants, offers a variety of potential advantages for use in the esthetic area of dentistry due to its tooth-like color. Zirconium dental implants are considered to be an alternative method of treatment to conventional titanium dental implants for patients with a thin gingival biotype. OBJECTIVES:This study was designed to study the bone tissue response to new zirconia implants with modified surfaces in comparison with commercially available titanium dental implants and commercially available zirconia implants. MATERIAL AND METHODS:The study was carried out on a group of 12 16-month-old minipigs. New zirconia implants with 3 different surfaces were used: M1 - blasted surface, M2 - etched surface and M3 - blasted and etched surface (Maxon Motor GmbH, Sexau, Germany) and compared to conventional titanium implants with an sandblasted and acid etched (SLA) surface (Straumann GmbH, Freiburg, Germany) and commercially available zirconia implants (Ziterion GmbH, Uffenheim, Germany). Histological and micro-computed tomopgraphy (micro-CT) evaluation was performed. RESULTS:In the micro-CT assessment, the average bone-implant contact (BIC) of the zirconia experimental implants was 41.44%. In particular, the BIC% for M1 was 39.72%, for M2 it was 43.97%, and for M3 - 40.63%; in the control group it was 49.63% and 27.77% for ceramic and titanium control implants, respectively. The intra-group analysis showed no statistically important differences between the BIC values for implants in any group. However, the analysis of BIC for different regions of the same implant showed statistically significant differences in all of the groups between the results of the threaded region and the neck and the apex. CONCLUSIONS:The results of our study suggest that zirconia implants with modified surfaces display features of osseointegration similar to those of titanium implants. These results are promising in using zirconia implants for dental applications in the future. 10.17219/acem/69246
    An In Vitro Study to Evaluate and Compare the Hemocompatibility of Titanium and Zirconia Implant Materials after Sandblasted and Acid-etched Surface Treatment. Rajan Arjun,Sivarajan Sujith,Vallabhan Chitra G,Nair Anjana S,Jayakumar Shilpa,Pillai Arya S The journal of contemporary dental practice AIM:This study was aimed to investigate the hemocompatibility of zirconia and titanium implant materials after surface treatment with sandblasting and acid etching (SLA). MATERIALS AND METHODS:Sixty specimens were procured from manufacturers of dimension 10mm × 3mm, thirty of each were prefabricated medical grade titanium (Ti-6Al-4V) and thirty of sintered zirconia. Silicon carbide grit papers of 240 to 1200pm, was used to polish the specimen surface. The surfaces were rinsed with water to remove any remnant particles after polishing. Later ultrasonic cleaning was done for 5 minutes using distilled water. The control specimens included 15 specimens each from titanium (groups A1) and zirconia (groups B1). The remaining 15 specimens (groups A2 and B2) were sandblasted using alumina particles of 150 microns particle size and using 20% hydrochloric acid, acid etching was done for 30 seconds. The specimens were scanned under electron microscope after surface treatment for analysis purpose and evaluated for surface characteristics. Before the exposure of specimens to blood, percentage hemolysis, prothrombin, platelet aggregation and activation, and thrombin time values were calculated. one mL of blood was added to each specimen for testing. The values before and after the exposure of specimens to blood were noted. Using a t-test, the values noted were statistically Results: A (polished titanium) showed highest mean values after exposure, in platelet count (184.67 ± 1.29), leucocyte count (7.27 ± 0.08), and thrombin time (10.15 ± 0.34) while prothrombin time's highest mean value after exposure were showed by A (SLA treated titanium) with a mean value of 10.04 ± 0.24. CONCLUSION:Surface treatment with sandblasting and acid etching (SLA) using 150 microns alumina particles and 20% hydrochloric acid increased the surface roughness of the titanium and zirconia implant materials and polished titanium showed maximum hemocompatibility. CLINICAL SIGNIFICANCE:The implant's success depends on its biocompatibility and its property of osseointegration. The adverse interaction between blood and the artificial surface is detected by the hemocompatibility test for medical materials, to know if the surface can activate or destruct the blood components. The success of implant placement also depends on the interaction between the blood and the specimen.
    Zirconia surface modifications for implant dentistry. Schünemann Fernanda H,Galárraga-Vinueza María E,Magini Ricardo,Fredel Márcio,Silva Filipe,Souza Júlio C M,Zhang Yu,Henriques Bruno Materials science & engineering. C, Materials for biological applications BACKGROUND:Zirconia has emerged as a versatile dental material due to its excellent aesthetic outcomes such as color and opacity, unique mechanical properties that can mimic the appearance of natural teeth and decrease peri-implant inflammatory reactions. OBJECTIVE:The aim of this review was to critically explore the state of art of zirconia surface treatment to enhance the biological and osseointegration behavior of zirconia in implant dentistry. MATERIALS AND METHODS:An electronic search in PubMed database was carried out until May 2018 using the following combination of key words and MeSH terms without time periods: "zirconia surface treatment" or "zirconia surface modification" or "zirconia coating" and "osseointegration" or "biological properties" or "bioactivity" or "functionally graded properties". RESULTS:Previous studies have reported the influence of zirconia-based implant surface on the adhesion, proliferation, and differentiation of osteoblast and fibroblasts at the implant to bone interface during the osseointegration process. A large number of physicochemical methods have been used to change the implant surfaces and therefore to improve the early and late bone-to-implant integration, namely: acid etching, gritblasting, laser treatment, UV light, CVD, and PVD. The development of coatings composed of silica, magnesium, graphene, dopamine, and bioactive molecules has been assessed although the development of a functionally graded material for implants has shown encouraging mechanical and biological behavior. CONCLUSION:Modified zirconia surfaces clearly demonstrate faster osseointegration than that on untreated surfaces. However, there is no consensus regarding the surface treatment and consequent morphological aspects of the surfaces to enhance osseointegration. 10.1016/j.msec.2019.01.062