加载中

    Classification of maxillary central incisors-implications for immediate implant in the esthetic zone. Lau Sze Lok,Chow James,Li William,Chow Lop Keung Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons PURPOSE:This is the first study to analyze the positions and angulations of the central maxillary incisors with reference to the alveolus, providing data for clinicians to achieve good esthetic results for immediate implant placement in the esthetic zone. MATERIALS AND METHODS:A total of 300 cone beam images were selected randomly. Five aspects were measured: the thickness of the palatal and buccal bone at their mid-root and apical level and the apical bone height. A classification was established according to the positions and angulations of the tooth. RESULTS:The data from 170 cone beam images were included in the present study. The mean thickness of the buccal bone at the mid-root level was 0.9 ± 0.4 mm and at the apical level was 2.04 ± 1.01 mm. The mean thickness of the palatal bone at the mid-root level was 3.76 ± 1.37 mm and at the apical level was 8.51 ± 2.54 mm. The mean apical bone height was 9.53 ± 2.76 mm. The proportion of incisors positioned more buccally (type B) was 78.8%, 19.4%, and 1.8% positioned midway (type M) and more palatally (type P), respectively. Regarding the angulation, 49.9% were classified as type 2 (toward buccal), 34.7% as type 3 (toward buccal, with the long axis anterior to the A point), and 15.4% were categorized as type 1 (toward palatal or parallel to the alveolus). CONCLUSIONS:We recommend that clinicians appreciate the socket in 3 dimensions to achieve a good outcome. According to the difficulty of achieving good results, the cases were categorized as levels I to III and recommendations were given. 10.1016/j.joms.2010.07.074
    Mandibular two implant-supported overdentures as the first choice standard of care for edentulous patients--the York Consensus Statement. Thomason J Mark,Feine Jocelyne,Exley Catherine,Moynihan Paula,Müller Frauke,Naert Ignace,Ellis Janice S,Barclay Craig,Butterworth Chris,Scott Brendan,Lynch Christopher,Stewardson Dominic,Smith Philip,Welfare Richard,Hyde Paul,McAndrew Robert,Fenlon Michael,Barclay Stewart,Barker Dean British dental journal The Annual Conference of the BSSPD (British Society for the Study of Prosthetic Dentistry) was held in York on 6 and 7 April 2009. At the symposium on mandibular overdentures, presenters offered a synopsis of the research available on the efficacy of implant-supported mandibular overdentures in the edentulous mandible. Emphasis was given to both qualitative and quantitative research based on patient-centred outcomes of treatment. A draft consensus was circulated to all presenters and to the Council members of the BSSPD and to BSSPD members on the Society's website. The statement was modified in the light of their comments, audience feedback following the presentations and members' feedback. We hope that this consensus statement will be a useful guide for patients and clinicians and that it will act to stimulate wider debate. We also hope that it will prove useful to other patient and professional organisations and will inform discussions with providers of national healthcare and with independent funders. 10.1038/sj.bdj.2009.728
    The McGill Consensus Statement on Overdentures. Mandibular 2-implant overdentures as first choice standard of care for edentulous patients. Thomason J Mark The European journal of prosthodontics and restorative dentistry
    Prosthodontic complications with implant overdentures: a systematic literature review. Andreiotelli Marina,Att Wael,Strub Jörg-Rudolf The International journal of prosthodontics PURPOSE:Problems associated with a complete denture, such as lack of stability and retention, can be solved with the use of implant-retained or implant-supported overdentures. However, controversy exists as to the anchorage system used and indications for both the maxilla and mandible. The purpose of this review was to identify the prosthetic complications associated with the different attachment mechanisms used for implant-supported or implant-retained overdentures. MATERIALS AND METHODS:A search of the MEDLINE and PubMed databases was conducted to find articles in English and German peer-reviewed journals published between 1980 and 2008. The search focused on randomized controlled clinical trials and prospective studies with follow-up periods of at least 5 years that contained clinical data regarding success, failure, and prosthetic complications. RESULTS:The search yielded a limited number of randomized controlled clinical trials referring to implant-supported or implant-retained overdentures. Very few studies have prospectively compared prosthetic complications for a period longer than 5 years after delivery of the prosthesis. CONCLUSIONS:Implant-supported or implant-retained overdentures in the mandible provide predictable results with improved stability, retention, and patient satisfaction. Scientific evidence shows a lower rate of implant survival and a higher frequency of prosthetic complications for maxillary implant-retained or implant-supported overdentures. Although the literature presents considerable information on complications of implant prostheses, variations in study design preclude proper analysis of certain complications. Well-designed longitudinal studies are required to establish evidence-based treatment planning principles.
    Overdenture attachment selection and the loading of implant and denture-bearing area. Part 2: A methodical study using five types of attachment. Heckmann S M,Winter W,Meyer M,Weber H P,Wichmann M G Clinical oral implants research In general, an implant is loaded via axial and horizontal forces. Besides this, moment loading can also occur. The aim of this study was to investigate how different prosthetic connectors with overdentures develop force transfer to implant and bone as well as to the denture-bearing alveolar ridge. Five connectors were investigated on a stereolithographic model fabricated according to a real patient situation. The model was fitted with strain gauges on the "bone" distal and medial to the implants and with vertical force transducers in the alveolar "bone" under the denture-bearing area. The parallel-sided rigid telescopic connector developed the highest moment loading of the implant (P<0.001), which would suggest restraint in the use of this connector. The bar construction also showed somewhat high moments but these may have been at least partly exaggerated by the individual patient situation. Loading results through the non-rigid telescopic copings, single spherical attachments and magnet overdentures demonstrated a low level of implant moment loading which would in part result from horizontal forces caused by denture forward shift during force application. The denture-bearing area loading was different with all attachments (P<0.001) and was related to the rigidity of the connector and reached the highest values with the non-rigid telescopic coping. The clinical implications of the various findings are discussed. 10.1034/j.1600-0501.2001.120613.x
    Effectiveness of maxillary overdentures supported by implants: maintenance and prosthetic complications. Kiener P,Oetterli M,Mericske E,Mericske-Stern R The International journal of prosthodontics PURPOSE:The aim of this study was to evaluate the prosthetic complications with implant-supported overdentures in the maxilla. MATERIALS AND METHODS:Forty-one patients (mean age 61 years) were consecutively admitted for treatment from 1991 to 1998. A total of 173 ITI implants were placed. Four to six implants either connected with a bar (34 overdentures) or with single anchors (seven overdentures) supported the denture, and only a few parties had fewer than four implants. The overdentures had a horseshoe design and were reinforced by a cast-metal framework. The mean observation time was 3.2 years. Oral hygiene and periimplant parameters were regularly assessed, and records were kept of prosthetic maintenance service. All prosthetic complications encountered were classified related to (1) implant components and anchorage devices, (2) mechanical and structural failures of dentures, or (3) denture-related adjustments. RESULTS:Three implants did not osseointegrate, and five implants were lost after loading. Thus, the overall survival rate of the implants was 95.5%. Altogether, 85 prosthetic complications were encountered. The most frequent finding was retightening of the bar screw and adjustments of the bar retainers. Repair of dentures was not frequent and was mostly related to broken teeth. No fracture of dentures was observed. Renewal of dentures occurred twice, once after loss of all implants in one patient. Thirty-nine overdentures had been continuously worn; thus, the overall denture stability was 95%. Mucosal irritation and need for occlusal adjustment were the most frequent findings in the first year. Over time, a decrease of complications was observed. CONCLUSION:Planned maxillary overdentures supported by implants are a successful treatment modality on a short-term basis.
    The effectiveness of different attachment systems maxillary and mandibular implant overdentures. Stafford Gary L Evidence-based dentistry Data sources Cochrane Oral Health's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, the US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform.Study selection Randomised controlled trials (RCTs), including cross-over trials on maxillary or mandibular implant overdentures with different attachment systems with at least one-year follow-up were considered. There were no restrictions on language or date of publication. Data extraction and synthesis Data were abstracted by four reviewers with risk of bias being assessed using the Cochrane tool. Data were combined using a fixed effects meta-analysis. The GRADE approach was used to assess the overall body of evidence.Results Six RCTs with a total of 294 mandibular overdentures were included. All of the trials were considered to be at high risk of bias. No studies on maxillary overdentures were included. For bar and ball attachments there was low quality evidence [two studies] that short-term re-treatment (repair of attachment system) was higher with ball attachments; RR =3.11(95%CI; 1.68 to 5.75) but no difference RR = 1.18(95%CI; 0.38 to 3.71) for replacements of attachment systems. There was no difference between ball and magnet systems in medium-term prosthodontic success or repair of attachment systems, but prosthodontic maintenance costs were higher when magnet attachments were used [one study - very low quality evidence]. Only one trial compared ball and telescopic attachments providing very low quality evidence. Conclusions For mandibular overdentures, there is insufficient evidence to determine the relative effectiveness of different attachment systems on prosthodontic success, prosthodontic maintenance, patient satisfaction, patient preference or costs. No trial evidence was available for maxillary overdentures. 10.1038/s41432-019-0011-z
    Locator Versus Bar Attachment Effect on the Retention and Stability of Implant-Retained Maxillary Overdenture: An In Vitro Study. ELsyad Moustafa Abdou,Dayekh Mahmoud Abdehamid,Khalifa Ahmed Khalifa Journal of prosthodontics : official journal of the American College of Prosthodontists PURPOSE:To compare retention and stability of Locator and bar attachments for implant-retained maxillary overdentures. MATERIALS AND METHODS:Four implants were inserted into a maxillary acrylic resin model in canines and second premolar areas. Experimental overdentures were connected to the implants with bar (group I) or Locator (group II) attachments. Locators were divided into 3 subgroups according the degree of retention of the patrix nylon insert: Locator blue (group IIa), Locator pink (group IIb), and Locator transparent (group IIc). Retention (vertical dislodging) and stability (lateral, anterior, posterior dislodging) forces (N) were measured at the start of the experiment (initial retention) and after 540 cycles of denture insertion and removal (final retention). RESULTS:The highest initial and final stability was recorded with group IIc, followed by group IIb and group IIa, and the lowest retention and stability was noted with group I. For all groups, the highest final retention and stability forces were noted with vertical dislodging, followed by posterior dislodging, anterior dislodging, and lateral dislodging. The highest loss of retention and stability was recorded with group I, followed by group IIc, group IIb, and group IIa. CONCLUSION:Locator attachments are recommended to retain maxillary overdentures over Dolder bar attachments, as Locator attachments were associated with high retention and stability after wear simulation with minimal retention loss. 10.1111/jopr.12608
    Complications associated with implant-retained removable prostheses. Vahidi Farhad,Pinto-Sinai Gitanjali Dental clinics of North America Implant-supported removable prostheses improve patients' satisfaction with treatment and quality of life. Improvements in the implant's surface and in attachment elements have made this treatment method very successful. However, some biological and mechanical complications remain. Mechanical complications associated with implant-supported overdentures and implant-supported removable partial dentures are loss of retention of attachment systems, the need to replace retention elements and to reline or repair the resin portion of the denture, and implant fracture. Despite their success, implant-supported removable prostheses require periodic maintenance. 10.1016/j.cden.2014.08.001
    Long-term, retrospective evaluation (implant and patient-centred outcome) of the two-implant-supported overdenture in the mandible. Part 2: marginal bone loss. Vercruyssen M,Quirynen M Clinical oral implants research OBJECTIVE:In part 2 of this long-term, retrospective study on the two-implant-supported overdenture in the mandible, the annual marginal bone loss was evaluated in detail and parameters, with a significant effect on the annual bone loss, were verified. MATERIAL AND METHODS:For all 495 patients with an overdenture in the mandible at least 5 years in function, data up to their last follow-up visit had been collected, including long-cone radiographs (taken at the abutment connection and after years 1, 3, 5, 8, 12 and 16 of loading) and probing data at their last evaluation. General information (medical history, implant data, report on surgery) was retrieved from the patient's file. Two hundred and forty-eight patients had been clinically examined recently. For the others, information on bone level and probing depths were retrieved from the patient's files, as all patients had been enrolled in our annual follow-up schedule. RESULTS:The mean annual bone loss on a site level (without considering the first year of bone remodelling) after 3 years of loading was 0.08 mm/year (SD=0.22, n=1105), after 5 years of loading 0.07 mm/year (SD=0.14, n=892), after 8 years of loading 0.06 mm/year (SD=0.12, n=598), after 12 years 0.04 mm/year (SD=0.07, n=370) and 0.05 mm/year (SD=0.05, n=154) after 16 years of loading. Ongoing bone loss was seen in a number of implants (n=26) with the annual bone loss exceeding 0.2 mm. Some factors clearly showed a significant impact on bone loss: smoking (> or =10 cigarettes/day), GBR, the presence of dehiscence and bone quantity(the latter only during the first year). The probing data showed a favourable condition, with <1.2% of the approximal pockets being > or =6 mm, and 4.1%=5 mm. CONCLUSIONS:The mean annual bone loss over the study period was <0.1 mm/year after the first year of loading. However, a small number (2.5%) of the implants showed continuing bone loss. 10.1111/j.1600-0501.2009.01902.x
    Long-term, retrospective evaluation (implant and patient-centred outcome) of the two-implants-supported overdenture in the mandible. Part 1: survival rate. Vercruyssen M,Marcelis K,Coucke W,Naert I,Quirynen M Clinical oral implants research OBJECTIVE:This retrospective analysis evaluated the long-term outcome of two implants supporting an overdenture in the mandible, as well as the significance of some confounding factors (smoking, implant length, bone quality). MATERIAL AND METHODS:All mandibular overdenture cases (n=495) treated during the past 25 years in our centre (with > or = 5 years loading of the implants) were included in this study. General information (medical history, implant data, report on surgery) was retrieved from the patient's file. A large number of patients (n=248) were willing to visit the clinic for an additional follow-up visit. For the others, information on implant survival was collected by phone (n=121), or contact was impossible (57 had died, three were hospitalized and 66 could not be reached). In the latter group, information was used, up to their last visit to the clinic. An implant was considered as surviving if it was still in function in the mouth, without clear adverse effects (pain, swelling, mobility). A failure was defined as early if it occurred within the window, insertion-final prosthesis placement; afterwards, it was considered as late. RESULTS:Most of the inserted implants (Brånemark type) were of the turned (machined) type (95.5%), the remainder was anodized (TiUnite). The anchoring system was either a bar (86.3%), ball attachments (11.7%) or magnets (1.6%), and only some patients changed from one to the other (0.4%). Kaplan-Meier analyses showed a survival rate of 95.5% after 20 years of loading. Factors that influenced the outcome included smoking (90% rate for smokers) and the surgical protocol (reduced survival rate for one-stage-placed implants). Implant length and bone quality had no impact. CONCLUSIONS:These results fully support the two-implant overdenture concept in the mandible even in the long run. 10.1111/j.1600-0501.2009.01849.x
    Tissue-supported dental implant prosthesis (overdenture): the search for the ideal protocol. A literature review. Laurito Domenica,Lamazza Luca,Spink Michael J,De Biase Alberto Annali di stomatologia AIMS:The success of maxillary and mandibular tissue supported implant prostheses varies in the literature, and the ideal protocol may be elusive from given the numerous studies. The oral rehabilitation option is an alternative to conventional dentures and should improve function, satisfaction, and retention. The purpose of this review article is to clarify these questions. METHODS:The search of literature reviews English non-anecdotal implant overdentures articles from 1991 to 2011. RESULTS:The results display an aggregate comprehensive list of categorical variables from the literature review. Overall success of maxillary and mandibular implant overdenture was respectively, 86.6% and 95.8%. CONCLUSION:The literature indicates that the implant overdenture prosthesis provides predictable results - enhanced stability, function and a high-degree of satisfaction compared to conventional removable dentures.
    The effects of fixed and removable implant-stabilised prostheses on posterior mandibular residual ridge resorption. Wright Paul S,Glantz Per-Olof,Randow Kjell,Watson Roger M Clinical oral implants research This study investigated the change over time in the area of the posterior mandibular residual ridge in patients wearing either i) mandibular overdentures stabilised by two implants (Brånemark System; Nobel Biocare, Göteborg, Sweden) connected by a bar, or ii) mandibular fixed cantilever prostheses stabilised on five or six implants. Proportional measurements were made in order to compare the area of the residual ridge with an area of bone uninfluenced by resorption. Measurements were made by digitising tracings of panoramic radiographs that were taken shortly after implant insertion and up to seven years later. With the use of overdentures, the posterior bone area index reduced by a mean of 1.1% per annum, while a mean bone area index increase of 1.6% per annum was demonstrated in association with fixed prostheses. A multiple linear regression model was fitted to predict the change in posterior area from type of prosthesis, gender, age, years of edentulism and initial height of the mandible. The model was only significant for initial height of mandible (P = 0.04) and type of prosthesis (P = 0.0001). In conclusion, patients rehabilitated with implant-stabilised mandibular overdentures demonstrated low rates of posterior mandibular residual ridge resorption, while patients rehabilitated with implant-stabilised mandibular fixed cantilever prostheses demonstrated bone apposition in the same area. 10.1034/j.1600-0501.2002.130207.x
    Maintenance requirements associated with mandibular implant overdentures: clinical results after first year of service. Bilhan Hakan,Geckili Onur,Mumcu Emre,Bilmenoglu Caglar The Journal of oral implantology The aim of this clinical study was to evaluate the prosthodontic maintenance requirements during the first year of service of mandibular overdentures supported by interforaminal implants and to assess the influence of attachment type, implant number, and bite force on these requirements. Fifty-nine patients treated with mandibular implant overdentures between the years 2004 and 2009 and appearing in the 12th-month recall were included in this study. The overdentures constituted 4 groups: 2 single interforaminal implants (1 group with locator and 1 group with ball attachments), 3 single interforaminal implants, 3 splinted interforaminal implants (bar), and 4 splinted interforaminal implants (bar). During the examination, prosthetic parameters such as occlusion, tissue adaptation, condition of the retentive mechanism (matrice and patrice), and the condition of the denture-bearing tissues were evaluated and recorded. No statistically significant relation was found between attachment type, bite force values, implant number, and the occurring complications except the need for relining, which was found significantly more in the ball attachments than in other attachment groups (P  =  .03). After 12 months following the overdenture insertion, there seems to be no relation between occurring complications and patient-related factors, such as maximum bite force, age, and gender, as well as factors related to the overdentures such as number and type of attachments. 10.1563/AAID-JOI-D-10-00096
    Long-term treatment outcomes in edentulous patients with implant overdentures: the Toronto study. Attard Nikolai J,Zarb George A The International journal of prosthodontics PURPOSE:Few long-term studies on overdentures report both implant and prosthodontic outcomes. The aim of this prospective study was to report long-term prosthodontic- and implant-related treatment outcomes of patients treated with design-specific implant-supported overdentures. MATERIALS AND METHODS:Between 1982 and 1992, 45 consecutively treated patients received a total of 47 overdentures (42 mandibular and 5 maxillary) supported by Brånemark implants. Prospective clinical and radiographic data were collected over the observation period; this study presents the most recent treatment outcomes. RESULTS:Thirty patients (mean age 70 years) with 32 prostheses attended the final recall visit, with 67% of patients followed for 15.53 years (range 10 to 19 years). Six implants failed, and the prosthetic plan and implant cumulative survival rates were both in excess of 90%. Mean marginal bone loss around implants after the first year of loading was small (0.05 mm/year), although the individual variation was high. Linear regression analysis of bone loss indicated that gender, bicortical stabilization, bone quality, and healing time were predictors of bone loss for the first year of loading but not for the ensuing years. Prosthetic maintenance included fractured components, denture relining, and replacement of prostheses. On average, the longevity of overdenture prostheses was 12 years, and laboratory relining was necessary every 4 years. CONCLUSION:This study confirmed the long-term outcome success of patients treated with design-specific overdenture prostheses supported by Brånemark implants. However, prosthetic maintenance was required, a fact that should be discussed with patients prior to treatment.
    Space requirements for implant-retained bar-and-clip overdentures. Phillips K,Wong K M Compendium of continuing education in dentistry (Jamesburg, N.J. : 1995)
    Classification of facial peri-implant soft tissue dehiscence/deficiencies at single implant sites in the esthetic zone. Zucchelli Giovanni,Tavelli Lorenzo,Stefanini Martina,Barootchi Shayan,Mazzotti Claudio,Gori Guido,Wang Hom-Lay Journal of periodontology BACKGROUND:The incidence of a peri-implant soft tissue dehiscence/deficiency (PSTD) is not a rare finding. Despite multiple previous attempts aimed at correcting the PSTDs, a classification of these conditions has not yet been proposed. This lack in the literature may also lead to discrepancies in the reported treatment outcomes and thus misinform the clinician or the readers. The aim of the present article was therefore to present a classification of peri-implant PSTD at a single implant site. METHODS:Four classes of PSTDs were discussed based on the position of the gingival margin of the implant-supported crown in relation to the homologous natural tooth. In addition, the bucco-lingual position of the implant head was also taken into consideration. Each class was further subdivided based on the height of the anatomical papillae. RESULTS:Subsequently, for each respective category a surgical approach (including bilaminar techniques, the combined prosthetic-surgical approach or soft tissue augmentation with a submerged healing) was also suggested. CONCLUSION:This paper provides a new classification system for describing PSTDs at single implant sites, with the appropriate recommended treatment protocol. 10.1002/JPER.18-0616
    Management of inter-dental/inter-implant papilla. Zetu Laura,Wang Hom-Lay Journal of clinical periodontology OBJECTIVES:The aims of this paper are to review and compare existing techniques for creation of interdental/interimplant papillae, to address factors that may influence its appearance and to present an approach that authors developed that could help clinicians to manage and recreate the interproximal papillae. METHODS:Papers related to interdental and interimplant papillae published over the last 30 years were selected and analyzed. RESULTS:Thorough treatment planning is essential for maintenance of the height of the interproximal papillae following tooth removal. The key for achieving an esthetically pleasing outcome is the clinicians' ability of properly managing/creating interdental/interimplant papillae. Bone support is the foundation for any soft tissue existence, techniques such as socket augmentation, orthodontic extrusion, guided bone regeneration, onlay graft and distraction osteogenesis are often used for this purpose. Soft tissue grafts as well as esthetic mimic restorations can also be used to enhance the esthetic outcomes. CONCLUSIONS:An esthetic triangle is developed to address the foundations that are essential for maintaining/creating papilla. These include adequate bone volume, proper soft tissue thickness as well as esthetic appearing restorations. 10.1111/j.1600-051X.2005.00748.x
    Treatment plan for restoring the edentulous maxilla with implant-supported restorations: removable overdenture versus fixed partial denture design. Zitzmann N U,Marinello C P The Journal of prosthetic dentistry STATEMENT OF PROBLEM:Restoring the edentulous maxilla with a fixed complete denture or a removable overdenture is a complex and challenging procedure. PURPOSE:This article presents and discusses the crucial factors involved in deciding whether a fixed or removable implant prosthesis should be planned in fulfilling the patient's preference for optimal esthetics, phonetics, comfort, and function. METHODS AND MATERIAL:A concept for treatment planning is presented that enables the practitioner to check the decisive parameters during the first examination and to make the final decision with the help of the reformatted computerized tomography scan. CONCLUSION:If this treatment plan is followed, implants can be placed to comply with the selected prosthetic solution and compromised solutions can be avoided. The fixed design for implant prosthesis is only appropriate for patients with minimal resorption of the alveolar bone and an optimal maxillomandibular relationship. The removable overdenture may be indicated from the outset and is no longer restricted to patients with a compromised situation in which fixed implant prostheses are not feasible. 10.1016/s0022-3913(99)70155-1
    [The modified lip-tooth-ridge classification: a guide for edentulous maxillary arches]. Liu Jian-Zhang Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology According to the width and height of the maxillary alveolar ridge, the maxillary edentulous jaws can be divided into three categories by using modified lip-tooth-ridge (MLTR) classification. Class Ⅰ is characterized by sufficient bone available for implants in the vertical and horizontal aspects and is suitable for fixed implant-supported prostheses. Class Ⅱ is characterized by sufficient bone amount available for implants in a horizontal aspect but insufficient for lip support and is suitable for a fixed detachable implant-supported prosthesis. Class Ⅲ is characterized by inadequate amount of bone for implants (with vertical or horizontal components) and is suitable for the use of zygomatic implants or traditional complete denture. Patients belonging to Class Ⅰ can be further classified into two sub-categories according to the height of the alveolar ridge. The first subclass is characterized by minimal bone deficiency and is suitable for a conventional implant-supported "crown and bridge" prosthesis. The second subclass is characterized by a larger vertical deficiency than that of the first subclass and is suitable for implant-supported hybrid prosthesis. The MLTR classification system can help the dentist to determine whether the patient is suitable for implanting dentures and whether fixed denture or removable denture is appropriate for the patient, select indications, reduce complications, and achieve long-term results. 10.7518/hxkq.2018.03.001
    Virtual implant planning in the edentulous maxilla: criteria for decision making of prosthesis design. Avrampou Marianna,Mericske-Stern Regina,Blatz Markus B,Katsoulis Joannis Clinical oral implants research OBJECTIVES:To evaluate prosthetic parameters in the edentulous anterior maxilla for decision making between fixed and removable implant prosthesis using virtual planning software. MATERIAL AND METHODS:CT- or DVT-scans of 43 patients (mean age 62 ± 8 years) with an edentulous maxilla were analyzed with the NobelGuide software. Implants (≥3.5 mm diameter, ≥10 mm length) were virtually placed in the optimal three-dimensional prosthetic position of all maxillary front teeth. Anatomical and prosthetic landmarks, including the cervical crown point (C-Point), the acrylic flange border (F-Point), and the implant-platform buccal-end (I-Point) were defined in each middle section to determine four measuring parameters: (1) acrylic flange height (FLHeight), (2) mucosal coverage (MucCov), (3) crown-Implant distance (CID) and (4) buccal prosthesis profile (ProsthProfile). Based on these parameters, all patients were assigned to one of three classes: (A) MucCov ≤ 0 mm and ProsthProfile≥45(0) allowing for fixed prosthesis, (B) MucCov = 0-5 mm and/or ProsthProfile = 30(0) -45(0) probably allowing for fixed prosthesis, and (C) MucCov ≥ 5 mm and/or ProsthProfile ≤ 30(0) where removable prosthesis is favorable. Statistical analyses included descriptive methods and non-parametric tests. RESULTS:Mean values were for FLHeight 10.0 mm, MucCov 5.6 mm, CID 7.4 mm, and ProsthProfile 39.1(0) . Seventy percent of patients fulfilled class C criteria (removable), 21% class B (probably fixed), and 2% class A (fixed), while in 7% (three patients) bone volume was insufficient for implant planning. CONCLUSIONS:The proposed classification and virtual planning procedure simplify the decision-making process regarding type of prosthesis and increase predictability of esthetic treatment outcomes. It was demonstrated that in the majority of cases, the space between the prosthetic crown and implant platform had to be filled with prosthetic materials. 10.1111/j.1600-0501.2011.02407.x
    Long-term treatment outcomes in edentulous patients with implant-fixed prostheses: the Toronto study. Attard Nikolai J,Zarb George A The International journal of prosthodontics PURPOSE:The aim of this prospective study was to report long-term treatment outcomes (prosthetic and implant related) of edentulous patients treated with implant-supported fixed prostheses who participated in the first clinical implant study in North America. MATERIALS AND METHODS:Forty-five patients were treated with Brånemark implants supporting a total of 47 fixed prostheses (42 mandibular and 5 maxillary) between 1979 and 1984. All patients were recalled regularly for comprehensive prospective clinical and radiographic assessments. RESULTS:Thirty-one patients (33 prostheses) attended a final recall visit in 2002; 71% of patients had been followed for 20 years (range 18 to 23 years), with overall prosthetic plan and implant outcome success rates of 84% and 87%, respectively. Mean marginal bone loss around the implants after the first year of loading was small (0.05 mm/year), with high individual variations. Poor oral hygiene, smoking history, and implant position appeared to be predictors of marginal bone loss. Prosthetic maintenance was ongoing and included fractured components and replacement of prostheses; the longevity of a fixed prosthesis for this group of patients was 8.39+/-5.30 years. CONCLUSION:This study confirmed the overall long-term treatment outcome success of patients treated with fixed prostheses supported by Brånemark implants. Successful osseointegration with a small mean bone loss was maintained as study patients aged, although prosthetic maintenance was required. The latter consideration should be discussed with all patients seeking such treatment.
    Retention mechanisms and prosthetic complications of implant-supported mandibular overdentures: long-term results. Dudic Alexander,Mericske-Stern Regina Clinical implant dentistry and related research BACKGROUND:Although many studies report high survival rates of mandibular implants supporting an overdenture, complications with prostheses and the need for prosthetic maintenance are not so well documented. PURPOSE:The purpose of the present study was to analyze three categories of prosthetic complications in relation to the type of retention mechanism for overdenture connection to the implants (ie, rigid or resilient). MATERIALS AND METHODS:One hundred nineteen patients with a total of 258 implants participated in the study. They had been monitored regularly during an observation period of 5 to 15 years (mean 9.3 yr). Seventy-five patients had a resilient retention device (ball anchors or a round clip bar); 44 patients had a rigid bar with or without distal extensions. The incidence and rate of complications were calculated for the overall- and for the 2- and 5-year observation periods. Comparisons were made between the three categories of maintenance and the two types of retention. A Kaplan-Meier analysis was applied for calculations of changes of the retention mechanism. RESULTS:The mean number of complications per overdenture during the entire observation period was 3.5; this did not differ statistically between the two retention groups. Some significant differences were found only for the 2- and 5- year period. Broken, loose, or lost female parts were more frequently observed with resilient devices, as were repairs and relining of the resin denture base, whereas tightening of bar retainers was more typical with rigid bars. A change from a resilient retention device to a rigid bar was performed more often than vice versa but not at a statistically significant level. CONCLUSION:Although these long-term results do not indicate a significant difference between the retention groups, a slight superiority of the rigid bar is suggested. 10.1111/j.1708-8208.2002.tb00173.x
    The implant-supported overdenture as an alternative to the complete mandibular denture. Doundoulakis James H,Eckert Steven E,Lindquist Clarence C,Jeffcoat Marjorie K Journal of the American Dental Association (1939) BACKGROUND:Approximately one-third of Americans older than 65 years of age are fully edentulous, requiring replacement of missing teeth. While the conventional denture may meet the needs of many patients, others require more retention, stability, function and esthetics, especially in the mandible. The implant-supported prosthesis is an alternative to the conventional removable denture. METHODS:This article describes the strengths of the implant-supported mandibular overdenture. The authors also outline the risks of this approach. They performed a review of recent literature to summarize the reported success rate of implants used to support a mandibular overdenture. RESULTS:The literature review indicates that implants placed in the anterior mandible (anterior to the foramen) have a success rate better than 95 percent. Patients have reported a high degree of satisfaction with the implant-supported overdenture. CONCLUSIONS:The literature indicates that implant-supported overdentures in the mandible provide predictable results with improved stability, retention, function and patient satisfaction compared with conventional dentures. Implants placed in the anterior mandible have a success rate equal to or greater than 95 percent. CLINICAL IMPLICATIONS:When planning treatment for patients with edentulous mandibles, clinicians should consider the implant-supported prosthesis. 10.14219/jada.archive.2003.0073
    Complications associated with the ball, bar and Locator attachments for implant-supported overdentures. Cakarer Sirmahan,Can Taylan,Yaltirik Mehmet,Keskin Cengizhan Medicina oral, patologia oral y cirugia bucal BACKGROUND:The purpose of this clinical study was to evaluate the complications associated with the different attachments used in implant-supported overdentures, including prosthetic problems and implant failures. A comparison of ball, bar and Locator (Zest Anchors, Inc, homepage, Escondido, CA, USA) attachments, in completely edentulous patients with two, three or four implants, was conducted. MATERIAL AND METHODS:A total of 36 edentulous patients (20 female, 16 male) with a mean age of 66.3 years, were enrolled in the study. The patients were treated with 95 implants, for the prosthetic restoration of the maxilla or the mandible. The mean follow-up time was 41.17 months. Prosthetic complications including, fractured overdentures, replacements of O-ring attachment and retention clips, implant failures, hygiene problems, mucosal enlargements, attachment fractures, retention loss and dislodgement of the attachments were recorded and evaluated. The recall visits at 3, 6, 12 months and, annually thereafter. RESULTS:Fourteen complications in the ballattachment group and 7 complications in the bar group were observed. No complications were observed in the locator group. The difference was found to be as statistically significant (p=0,009). Six of the 95 implants had failed. Totally 39 implant overdentures were applied. Three prostheses were renewed because of fractures. CONCLUSION:Within the limits of the present study, it was concluded that the locator system showed superior clinical results than the ball and the bar attachments, with regard to the rate of prosthodontic complications and the maintenance of the oral function. 10.4317/medoral.17312
    Fixed-prosthetic implant restoration of the edentulous maxilla: a systematic pretreatment evaluation method. Bedrossian Edmond,Sullivan Richard M,Fortin Yvan,Malo Paulo,Indresano Thomas Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons 10.1016/j.joms.2007.06.687
    Vertical distance from the crest of bone to the height of the interproximal papilla between adjacent implants. Tarnow Dennis,Elian Nicolas,Fletcher Paul,Froum Stuart,Magner Ann,Cho Sang-Choon,Salama Maurice,Salama Henry,Garber David A Journal of periodontology BACKGROUND:As patient demand increases for more natural restorations in the esthetic zone, clinicians must have the highest level of skill and knowledge to maintain or reform the interdental papilla between teeth, between implants and teeth, and between adjacent implants. To date, there are no reports that have measured the distance from the contact point to the bony crest between implants. One reason for this may be the fact that, with two adjacent implants, the contact point of the crown can be established at any distance from the gingival margin according to the restorative dentist's specifications. Therefore, in this study, the height of the soft tissue to the crest of bone was measured between two adjacent implants independent of the location of the contact point. The purpose of this study was to determine the range and average height of tissue between two adjacent implants. METHODS:A total of 136 interimplant papillary heights were examined in 33 patients by eight different examiners in five private dental offices. After administration of appropriate local anesthesia, a standardized periodontal probe was placed vertically from the height of the papilla to the crest of bone. The measurements were rounded off to the nearest millimeter. RESULTS:The mean height of papillary tissue between two adjacent implants was 3.4 mm, with a range of 1 mm to 7 mm. CONCLUSIONS:Clinicians should proceed with great caution when placing two implants adjacent to each other in the esthetic zone. In most cases, only 2, 3, or 4 mm of soft tissue height (average 3.4 mm) can be expected to form over the interimplant crest of bone. These results showed that modification of treatment plans may be necessary when esthetics are critical for success. 10.1902/jop.2003.74.12.1785
    The effectiveness of immediate, early, and conventional loading of dental implants: a Cochrane systematic review of randomized controlled clinical trials. Esposito Marco,Grusovin Maria Gabriella,Willings Mark,Coulthard Paul,Worthington Helen V The International journal of oral & maxillofacial implants PURPOSE:To test whether there is a difference in success rates between immediately, early, and conventionally loaded implants. MATERIALS AND METHODS:All randomized controlled clinical trials (RCTs) of root-form osseointegrated oral implants having a follow-up of 6 months to 1 year comparing the same osseointegrated root-form oral implants loaded immediately (within 1 week); early (between 1 week to 2 months); or conventionally (after 2 months) were eligible. An exhaustive search was conducted with no language restriction on January 15, 2007. Outcome measures were prosthesis failures, implant failures, and marginal bone levels measured on intraoral radiographs. Screening of eligible studies, quality assessment, and data extraction were conducted in duplicate. Authors were contacted for any missing information. Results were expressed as random effects models using weighted mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals. The statistical unit of the analysis was the patient. RESULTS:Twenty RCTs were identified, and 11 trials including a total of 300 patients were included. Six trials compared immediate versus conventional loading, 3 early versus conventional loading, and 2 immediate versus early loading. None of the meta-analyses revealed any statistically significant differences. CONCLUSIONS:It is possible to successfully load dental implants immediately or early after their placement in selected patients, although not all clinicians may achieve optimal results. A high degree of primary implant stability (high value of insertion torque) seems to be 1 of the prerequisites for a successful immediate/early loading procedure. More well-designed RCTs are needed. Priority should be given to trials comparing immediately versus early loaded implants. These trials should be reported according to the CONSORT guidelines (www.consort-statement.org).
    High versus low implant insertion torque: a histologic, histomorphometric, and biomechanical study in the sheep mandible. Trisi Paolo,Todisco Marzio,Consolo Ugo,Travaglini Domenico The International journal of oral & maxillofacial implants PURPOSE:The purpose of this study was to analyze, in an animal model, the histologic and biomechanical phenomena at the bone-implant interface of implants inserted with high torque (HT) as compared to low torque (LT) during the first 6 weeks of healing. MATERIALS AND METHODS:Forty tapered-screw-form implants were placed in five hybrid sheep. The implant sites were placed in the mandible, using an extraoral approach; four were placed with HT (test: mean 110 Ncm) on one side and four were placed with LT (control: mean 10 Ncm) on the contralateral side. After 1, 2, 3, 4, and 6 weeks of healing, removal torque testing and resonance frequency analysis were performed and the animals were sacrificed for histologic examination. RESULTS:Implants from the HT group showed significantly higher bone apposition than implants from the LT group at all examined healing times. Similarly, removal torque was consistently higher for the HT as compared to the LT group. A significant loss of primary stability in the HT group was evident 7 days after placement. Implants from the LT group achieved a significant increase in stability after 4 weeks. Resonance frequency analysis was unable to detect these histologic and biomechanical modifications of the bone-implant complex. CONCLUSIONS:The results of the study showed that high implant insertion torque in dense cortical bone does not induce bone necrosis or implant failure, but it does increase the primary stability of implants, which is extremely important in immediate loading protocols.
    Nasopalatine canal position relative to the maxillary central incisors: a cone beam computed tomography assessment. Chatriyanuyoke Pakawat,Lu Chun-I,Suzuki Yusuke,Lozada Jaime L,Rungcharassaeng Kitichai,Kan Joseph Y K,Goodacre Charles J The Journal of oral implantology The aim of this study was to determine the proximity of the nasopalatine canal (NPC) to the maxillary central incisor root (MCIR). The study included 120 cone beam computed tomography scans obtained from the Center for Implant Dentistry, Loma Linda University, between June 2006 and September 2009. They were equally distributed into six groups: (1) 21- to 40-year-old men, (2) 21- to 40-year-old women, (3) 41- to 60-year-old men, (4) 41- to 60-year-old women, (5) 61- to 80-year-old men, and (6) 61- to 80-year-old women. The closest distances between the NPC and the MCIR (NPC-to-MCIR) were measured at the midroot (bisecting palatal cementoenamel junction to root apex) and the apex levels. Differences between the groups were analyzed using a t test and 1-way analysis of variance at a significance level of α = .05. The overall mean NPC-to-MCIR distances at the midroot and apex levels were 3.05 ± 1.64 and 5.22 ± 1.56 mm, respectively. The modes of the NPC-to-MCIR distances at the midroot and apex levels were in the range of 1.01-2.00 mm and 4.01-5.00 mm, respectively. The mean NPC-to-MCIR distance was significantly greater in men than in women at the midroot level (P < .05) but not at the apex level (P > .05). The mean NPC-to-MCIR distance was significantly shorter for the youngest age group than the other two age groups at the midroot level (P < .05). However, at the apex level, the youngest age group had a significantly shorter distance compared with the oldest age group (P < .05) but not the middle age group (P > .05). The results of this study suggest that, to avoid NPC penetration, more care must be exercised during immediate implant placement at the midroot level of a maxillary central incisor in women and younger patients because of the root proximity to the NPC. Tapered implants may also be beneficial in such situations. 10.1563/AAID-JOI-D-10-00106
    10 Keys for Successful Esthetic-Zone Single Implants: Importance of Biotype Conversion for Lasting Success. Levine Robert A,Ganeles Jeffrey,Kan Joseph,Fava Phil L Compendium of continuing education in dentistry (Jamesburg, N.J. : 1995) The concept of 10 keys for successful esthetic-zone single immediate implants is an evidenced-based summary for the treatment planning and replacement of a hopeless tooth in the maxillary anterior sextant. It includes two treatment-planning, five surgical, and three prosthetic keys. These keys are aimed at minimizing soft- and hard-tissue complications to achieve an optimal long-term esthetic implant restoration. Based on the 10 keys, which were described in a prior publication and are reiterated herein, the management of an immediate implant in the esthetic zone is considered a complex SAC procedure (SAC = straightforward, advanced, and complex). The present article highlights the importance of connective tissue grafting as part of the 10 keys and its role in biotype conversion and esthetic success that endures.
    Immediate implant placement and provisionalization of maxillary anterior single implants. Kan Joseph Yun Kwong,Rungcharassaeng Kitchai,Deflorian Matteo,Weinstein Tommaso,Wang Hom-Lay,Testori Tiziano Periodontology 2000 An inevitable loss of soft and hard tissue after tooth extraction often results in a compromised site for anterior implant esthetics in both vertical and horizontal dimensions. Immediate implant placement and provisionalization has been a viable option for replacing failing maxillary anterior teeth as it preserves the vertical existing osseous and gingival architecture. With the simultaneous addition of soft- and hard-tissue grafts, the peri-implant horizontal tissue topography can also be maintained. The esthetic success of immediate implant placement and provisionalization procedures is influenced by a number of factors that can be identified as patient-dependent or clinician-dependent. This article describes in detail the process of patient selection, indications, contraindications, diagnosis, treatment planning and treatment execution required to achieve functional and esthetic success with immediate implant placement and provisionalization. 10.1111/prd.12212
    Restorative Emergence Profile for Single-Tooth Implants in Healthy Periodontal Patients: Clinical Guidelines and Decision-Making Strategies. Chu Stephen J,Kan Joseph Yk,Lee Ernesto A,Lin Guo-Hao,Jahangiri Leila,Nevins Myron,Wang Hom-Lay The International journal of periodontics & restorative dentistry The peri-implant soft tissue seal consists of a connective tissue cuff and a junctional epithelium that is different from the arrangement of periodontium around a natural tooth. However, the peri-implant soft tissue complex lacks Sharpey's fibers, thus offering less resistance to clinical probing and biofilm penetration compared to the natural dentition. Therefore, the proper restorative emergence profile design is essential to facilitate favorable esthetic outcomes and maintain peri-implant health. The aim of this article is to review the currently available evidence related to the design of subgingival (critical and subcritical) and supragingival contours of the implant restorative emergence profile (IREP) as well as provide a flowchart for decision-making in clinical practice. Theoretically, the subgingival contours of the crown/abutment complex should mimic the morphology of the root and the cervical third of the anatomic crown as much and as often as possible. However, this is highly dependent upon the three-dimensional spatial position of the implant relative to the hard and soft tissue complex, in addition to the location of the definitive restoration. Frequently, a convex critical contour is required on the facial aspect of a palatally or incisally positioned implant to support an adequate gingival-margin architecture. Conversely, if the implant is placed too far facially, then a flat or concave contour is recommended. In instances where soft tissue support is not needed, the subcritical area may be undercontoured to increase the thickness, height, and stability of the soft tissue cuff. 10.11607/prd.3697
    Clinical and radiographic evaluation of the papilla level adjacent to single-tooth dental implants. A retrospective study in the maxillary anterior region. Choquet V,Hermans M,Adriaenssens P,Daelemans P,Tarnow D P,Malevez C Journal of periodontology BACKGROUND:The regeneration of gingival papillae after single-implant treatment is an area of current investigation. This study was designed to determine: 1) whether the distance from the base of the contact point to the crest of the bone would correlate with the presence or absence of interproximal papillae adjacent to single-tooth implants, and 2) whether the surgical technique at uncovering influences the outcome. METHODS:A clinical and radiographic retrospective evaluation of the papilla level around single dental implants and their adjacent teeth was performed in the anterior maxilla in 26 patients restored with 27 implants. Six months after insertion, 17 implants were uncovered with a standard technique, while 10 implants were uncovered with a technique designed to generate papilla-like formation around dental implants. Fifty-two papillae were available for clinical and radiographic evaluation. The presence or absence of papillae was determined, and the effects of the following variables were analyzed: the influence of the 2 surgical techniques; the vertical relation between the papilla height and the crest of bone between the implant and adjacent teeth; the vertical relation between the papilla level and the contact point between the crowns of the teeth and the implant; and the distance from the contact point to the crest of bone. RESULTS:When the measurement from the contact point to the crest of bone was 5 mm or less, the papilla was present almost 100% of the time. When the distance was > or = 6 mm, the papilla was present 50% of the time or less. The mean distance between the crest of bone and the most coronal papilla level (interproximal soft tissue height) was 3.85 mm (SD = 1.04). When comparing the conventional and modified surgical technique, the relation shifted from 3.77 mm (SD = 1.01) to 4.01 mm (SD = 1.10), respectively. CONCLUSIONS:These results clearly show the influence of the bone crest on the presence or absence of papillae between implants and adjacent teeth. The data also show a positive influence for the modified surgical technique, aimed at reconstructing papillae at the implant uncovering. 10.1902/jop.2001.72.10.1364
    Analysis of the socket bone wall dimensions in the upper maxilla in relation to immediate implant placement. Huynh-Ba Guy,Pjetursson Bjarni E,Sanz Mariano,Cecchinato Denis,Ferrus Jorge,Lindhe Jan,Lang Niklaus P Clinical oral implants research BACKGROUND:Animal and human researches have shown that immediate implant placement into extraction sockets failed to prevent socket dimensional changes following tooth extraction. It has been suggested that a minimal width of 1-2 mm of buccal bone is necessary to maintain a stable vertical dimension of the alveolar crest. AIM:To determine the dimensions of the bony wall at extraction sites in the esthetic zone (anterior teeth and premolars in the maxilla) and relate it to immediate implant placement. METHODS:As part of an ongoing prospective randomized-controlled multicenter clinical study on immediate implant placement, the width of the buccal and palatal bony walls was recorded at 93 extraction sites. RESULTS:The mean width of the buccal and palatal bony walls was 1 and 1.2 mm, respectively (P<0.05). For the anterior sites (canine to canine), the mean width of the buccal bony wall was 0.8 mm. For the posterior (premolar) sites, it was 1.1 mm (P<0.05). In the anterior sites, 87% of the buccal bony walls had a width < or = 1 mm and 3% of the walls were 2 mm wide. In the posterior sites, the corresponding values were 59% and 9%, respectively. CONCLUSIONS:If the criterion of a minimal buccal bone width of 2 mm to maintain a stable buccal bony wall is valid, only a limited number of sites in the anterior maxilla display such a clinical situation. The data suggested that in the majority of extraction sites in the anterior maxilla, thin (< or = 1 mm) buccal walls were present. This, in turn, means that in most clinical situations encountered, augmentation procedures are needed to achieve adequate bony contours around the implant. 10.1111/j.1600-0501.2009.01870.x
    Ridge alterations post-extraction in the esthetic zone: a 3D analysis with CBCT. Chappuis V,Engel O,Reyes M,Shahim K,Nolte L-P,Buser D Journal of dental research Dimensional alterations of the facial bone wall following tooth extractions in the esthetic zone have a profound effect on treatment outcomes. This prospective study in 39 patients is the first to investigate three-dimensional (3D) alterations of facial bone in the esthetic zone during the initial 8 wks following flapless tooth extraction. A novel 3D analysis was carried out, based on 2 consecutive cone beam computed tomographies (CBCTs). A risk zone for significant bone resorption was identified in central areas, whereas proximal areas yielded only minor changes. Correlation analysis identified a facial bone wall thickness of ≤ 1 mm as a critical factor associated with the extent of bone resorption. Thin-wall phenotypes displayed pronounced vertical bone resorption, with a median bone loss of 7.5 mm, as compared with thick-wall phenotypes, which decreased by only 1.1 mm. For the first time, 3D analysis has allowed for documentation of dimensional alterations of the facial bone wall in the esthetic zone of humans following extraction. It also characterized a risk zone prone to pronounced bone resorption in thin-wall phenotypes. Vertical bone loss was 3.5 times more severe than findings reported in the existing literature. 10.1177/0022034513506713