The International Journal of Oral & Maxillofacial Implants

Purpose: This overview was prepared to describe how an evidence-based approach was used to develop an Academy of Osseointegration (AO) Workshop on the State of the Science on Implant Dentistry (SSID). Materials and Methods: An AO SSID Workshop Planning Committee was appointed in 2001 to follow an evidence-based approach for reviewing published clinical data using strict inclusion and exclusion criteria in order to answer 8 closed-end 4-part clinical questions. A systematic approach was employed to assure coherent data management and analysis. Reviewers, co-reviewers, and a biostatistician were appointed. The workshop agenda was developed to include participants who had the primary responsibility for each of the 8 workshop sections to answer 5 consensus questions for the section's systematic review. The planned outcomes of the SSID Workshop included publication of the 8 consensus reports with their respective systematic reviews in The International Journal of Oral & Maxillofacial Implants (supplemental issue), 2007; the development of clinical guidelines responding to each of the 8 focused questions; and the identification and prioritization of questions or topics requiring further research. Results: The evidence-based approach was utilized successfully in planning and carrying out the AO SSID Workshop held on August 3-6, 2006, in Oak Brook, Illinois, and the subsequent publication of its proceedings. Discussion: Although successful in its objectives, the outcome of systematic reviews is only as good as the published data. Significant deficiencies in published implant studies were identified, including, but not limited to, a lack of randomized controlled prospective clinical trials, universal acceptance and publication of defined implant survival and success criteria, and clear questions with well-defined research design. Conclusion: The evidence-based approach can be used to systematically review the literature for a workshop on important questions related to implant dentistry. A major limitation is the lack of common outcome variables between published studies.

Meta-analyses have been widely used to estimate treatment effects in evidence-based dentistry. Few conferences, however, have used a systems approach to assure coherent data management and analysis. The purpose of this section is to describe the data management and statistical analysis for the State of the Science of Implant Dentistry (SSID) conference. This overview includes (a) a description of widely used clinical trial designs for implant dentistry, (b) a description of data management procedures specifically designed for the SSID conference, and (c) a description of the data analysis methodology, including descriptive analyses and meta-analyses. The use of the systems approach facilitated data abstraction and analysis.

Purpose: A systematic review of the available literature to assess the effects of time to loading of implants on treatment outcomes. Methods: PubMed search strategies identifying clinical trials on implant prosthetics, combined with searching of a personal library and reference lists from included studies, resulted in 1,882 titles published before May 1, 2005. Two independent reviewers appraised the titles and abstracts and identified 187 papers that seemed to focus on the effects of time to loading on treatment outcomes in clinical trials. These papers were retrieved and critically appraised in full text. A set of predefined inclusion and exclusion criteria were applied. All trials (randomized and nonrandomized clinical trials, prospective and retrospective) were included in the review if both an experimental and a control group were adequately described, if the implants had been followed for at least 1 year, and if the sample contained at least 5 patients. Results: Twenty-two papers, published between 1990 and 2005 described the influence of time to loading on implant treatment success. Seven trials were randomized controlled trials, 13 were prospective with concurrent controls, and 2 were retrospective with concurrent controls. The general impression of the papers was that (1) the methodologic rigor of the trials was often not very strong, (2) the reported treatment outcomes were mostly surrogate rather than patient-centered, and (3) the follow-up times were relatively short. Statistical comparisons between subgroups were considered inappropriate because of the heterogeneity of trials. Data from 19 trials reporting different patient follow-up periods between 1 and 10 years suggest that the overall performance was not significantly different between immediate or early loaded implants versus implants using a conventional loading period. Conclusion: Within the limitations of the study populations in the papers appraised in this systematic review, although the average outcome was in favor of delayed loading, there are no indications that immediate or early loading cannot be a safe procedure. Keywords: early loading, immediate loading, oral implants, osseointegration, prosthodontics

Purpose: A variety of techniques and materials have been used to establish the structural base of osseous tissue for supporting dental implants. The aim of this systematic review was to identify the most successful technique(s) to provide the necessary alveolar bone to place a dental implant and support long-term survival. Methods: A systematic online review of a main database and manual search of relevant articles from refereed journals were performed between 1980 and 2005. Updates and additions were made from September 2004 to May 2005. The hard tissue augmentation techniques were separated into 2 anatomic sites, the maxillary sinus and alveolar ridge. Within the alveolar ridge augmentation technique, different surgical approaches were identified and categorized, including guided bone regeneration (GBR), onlay/veneer grafting (OVG), combinations of onlay, veneer, interpositional inlay grafting (COG), distraction osteogenesis (DO), ridge splitting (RS), free and vascularized autografts for discontinuity defects (DD), mandibular interpositional grafting (MI), and socket preservation (SP). All identified articles were evaluated and screened by 2 independent reviewers to meet strict inclusion criteria. Articles meeting the inclusion criteria were further evaluated for data extraction. The initial search identified a total of 526 articles from the electronic database and manual search. Of these, 335 articles met the inclusion criteria after a review of the titles and abstracts. From the 335 articles, further review of the full text of the articles produced 90 articles that provided sufficient data for extraction and analysis. Results: For the maxillary sinus grafting (SG) technique, the results showed a total of 5,128 implants placed, with follow-up times ranging from 12 to 102 months. Implant survival was 92% for implants placed into autogenous and autogenous/composite grafts, 93.3% for implants placed into allogeneic/nonautogenous composite grafts, 81% for implants placed into alloplast and alloplast/xenograft materials, and 95.6% for implants placed into xenograft materials alone. For alveolar ridge augmentation, a total of 2,620 implants were placed, with follow-up ranging from 5 to 74 months. The implant survival rate was 95.5% for GBR, 90.4% for OVG, 94.7% for DO, and 83.8% for COG. Other techniques, such as DD, RS, SP, and MI, were difficult to analyze because of the small sample size and data heterogeneity within and across studies. Conclusions: The maxillary sinus augmentation procedure has been well documented, and the long-term clinical success/survival (> 5 years) of implants placed, regardless of graft material(s) used, compares favorably to implants placed conventionally, with no grafting procedure, as reported in other systematic reviews. Alveolar ridge augmentation techniques do not have detailed documentation or long-term follow-up studies, with the exception of GBR. However, studies that met the inclusion criteria seemed to be comparable and yielded favorable results in supporting dental implants. The alveolar ridge augmentation procedures may be more technique- and operator-experience-sensitive, and implant survival may be a function of residual bone supporting the dental implant rather than grafted bone. More in-depth, long-term, multicenter studies are required to provide further insight into augmentation procedures to support dental implant survival.

Purpose: The study provides a systematic review of the literature to determine the long-term survival characteristics of single implant-supported crowns and fixed partial dentures. Materials and Methods: A search of the MEDLINE, EMBASE, and Cochrane Collaboration databases was conducted to identify articles that compared survival and success of fixed partial dentures and single implant-supported crowns. In addition to comparative cohort studies, articles that pertained specifically to single implant-supported crowns or fixed partial dentures were included in this review. Inclusion criteria for implant and fixed partial denture articles included a minimum 2-year study, primary publication in the English language, a minimum of 12 implants, implants designed to osseointegrate, and inclusion of data regarding implant and prosthetic performance. Data were analyzed using cumulative proportions of survival and success for both prosthetic types and for individual implants. Wilson score method was used to establish 95% confidence intervals for each population. The chi-square test for homogeneity was performed. Results: The literature search failed to identify any articles that directly compared survival or success of single implant-supported restorations with fixed partial dentures. Following the search criteria, and independent analysis by reviewers, 51 articles were identified in the implant literature (agreement, 95.42%; kappa coefficient, 0.8976), and 41 were identified in the fixed partial denture literature (agreement, 90.97%; kappa coefficient, 0.7524). Pooled success of single-implant restorations at 60 months was 95.1% (CI: 92.2%-98.0%), while fixed partial dentures of all designs exhibited an 84.0% success rate (CI: 79.1%-88.9%). Conclusions: This systematic review of the scientific literature failed to demonstrate any direct comparative studies assessing clinical performance of single implant-supported crowns and tooth-supported fixed partial dentures. The analysis suggested differences at 60 months between survival of implant-supported single crowns and natural tooth-supported fixed prostheses when resin-bonded and conventionally retained fixed prostheses were grouped. This difference disappeared when implant-supported single crowns were compared with conventionally retained fixed partial dentures at 60 months. For other time periods, direct comparative data were unavailable. Keywords: etched bonded dentures, fixed partial dentures, implant-supported restorations, implant-supported single crowns, implant-supported single-tooth restorations, resin-bonded fixed partial denture, success, survival

Purpose: The clinical question this systematic review aimed to answer was "What are the differences in outcomes of restored endodontically treated teeth compared to implant-supported restorations? Therefore the aim of this study was to use systematic review to compare the survival of compromised teeth restored with either root canal therapy followed by a crown, or placement of a single-tooth implant. Materials and Methods: MEDLINE, EMBASE, and PubMed databases were searched for studies dealing with survival of single-tooth implants and restored endodontically treated teeth. A 2-step screening procedure was used to identify articles that met the inclusion/exclusion criteria. Fifty-five studies related to single-tooth implants and 13 studies related to restored root canal-treated teeth were included. The endpoint analyzed in these studies was the survival rate of the treated tooth or implant. Results: The 95% confidence intervals for the pooled estimates for the single-tooth implants and restored endodontically treated teeth were found overlapping in forest plots for all follow-up periods. This indicated no significant differences in survival between restored root canal-treated teeth and single-tooth implants. Conclusions: The results of this systematic review indicate that the decision to treat a tooth endodontically or replace it with an implant must be based on factors other than the treatment outcomes of the procedures themselves. Both nonsurgical root canal therapy followed by an appropriate restoration and single-tooth implants are excellent treatment modalities for the treatment of compromised teeth. Keywords: restored root canal-treated teeth, single-tooth implants, survival of root canal-treated restored teeth, survival of single-tooth implants, systematic review

Purpose: A systematic review, including meta-analysis, was conducted to answer the question "Does the type of implant prosthesis affect outcomes for the completely edentulous arch?" The current paper was to assess the impact of fixed or removable prosthesis type on implant survival and success outcomes. Materials and Methods: Pertinent literature was identified through December 31, 2005 using a PubMed search strategy and hand-searching of relevant journals, a personal library, and reference lists from included studies. Inclusion and exclusion criteria were applied to the titles and abstracts and subsequently to the full text of included references. The 72 included studies reported oral implant survival or success, crestal bone levels or loss, and/or prosthesis success or maintenance differentiated by arch and by prosthesis type (fixed or removable, splinted or nonsplinted) established either in 1-year randomized clinical trials or 5-year observational studies. Results: Statistical analysis revealed only a site-specific rather than a design-specific finding that implant survival for mandibular fixed prosthesis groups had a 6.6% greater implant survival than maxillary fixed prostheses groups (P .001). The observation of greater implant failure for removable over fixed protheses groups in the maxilla appeared likely due to deficient preoperative bone volume in the removable prosthesis groups. Discussion: There is little evidence that implant survival or success is affected directly by prosthesis type based on current designs studied for at least 5 years. Prosthesis maintenance does appear to vary with different prosthesis designs. Conclusion: While this study suggests implant survival and success may not be affected by variation across the established types of implant prostheses, maintenance demands can vary with implant prosthesis type, especially with overdenture attachments. Clinicians should remain diligent in basing implant prosthodontic technique on established protocols. Keywords: complete edentulism, evidence-based dentistry, fixed prostheses, meta-analysis, oral implants, removable prostheses, success, survival, systematic review

Purpose: Implant restoration of the partially edentulous patient has become highly predictable. The scientific information on the specifics of restorative designs and their influence on the long-term outcome is sparse. The main objective of this systematic review was to determine what scientific evidence exists regarding the influence of prosthodontic design features on the long-term outcomes of implant therapy (implant success and survival, prosthesis success and survival) in the partially edentulous patient. Materials and Methods: Four questions of primary interest regarding implant prosthodontic design options were selected by the 2 reviewers: abutment type, retention type (cemented, screw-retained), support type (implant support alone versus combined implant-tooth support), and the type of restorative material. Inclusion and exclusion criteria were formulated and applied to a total of 1,720 titles. The list of titles was primarily based on a PubMed-type search provided by the State of the Science of Implant Dentistry workshop leadership. It was supplemented by a hand search of relevant journals at the Countway Library of the Harvard Medical School and of a personal collection of relevant publications of the 2 reviewers. Information on the survival and success of implants and prostheses as defined by the respective authors was retrieved from the included articles, entered into data extraction tables, and submitted for statistical analysis. Results: Seventy-four articles were selected for data extraction and analysis after critical appraisal and application of the exclusion criteria. The kappa value for reviewer agreement was 100% between the 2 reviewers. The majority of studies were in the "average" range and were published between 1995 and 2003. Only 2 "best" trials, ie, randomized controlled clinical trials, were identified. For the method of retention (screw-retained versus cemented), no differences were found in implant success or survival rates between screw-retained and cemented restorations. Prosthesis success rates showed greater variations between cemented and screw-retained restorations at the various evaluation times; however, the differences never reached statistical significance. The prosthesis success rate at the last reported examination (> 72 mo) was 93.2% for cemented and 83.4% for screw-retained restorations (P > .05). Regarding the type of support, implant success rates at the last reported evaluation were 97.1% for implant-supported fixed partial dentures (FPDs), 94.3% for single-implant restorations, and 89.2% for implant-tooth-supported FPDs. None of the differences reached statistical significance. Implant survival at the last examination (> 72 mo) was highest for implant-supported FPDs (97.7%), followed by single-implant restorations (95.6%) and implant-tooth-supported FPDs (91.1%). Differences were not statistically significant. Prosthesis success at the last examination (> 72 mo) resulted in overall lower percentage rates than implant success or survival (89.7% for implant-supported FPDs, 87.5% for implant-tooth-supported FPDs, and 85.4% for single-implant restorations; differences not statistically significant). Insufficient extractable information was available regarding the influence of abutment type or restorative material. Conclusion: The scientific evidence obtained from this review is insufficient to establish unequivocal clinical guidelines for the design of implant-supported fixed prostheses in the partially edentulous patient.

Purpose: Implant therapy is highly predictable and successful. However, certain risk factors can predispose individuals to lower rates of success. The purpose of this systematic review was to evaluate the available literature to assess whether smoking, diabetes, and periodontitis have an adverse affect on the outcomes of implants placed in patients with these conditions. Materials and Methods: The dental literature was searched using the MEDLINE, Cochrane Collaboration, and EMBASE databases. Using specific inclusion and exclusion criteria, 2 reviewers evaluated titles, abstracts, and full articles to identify articles relevant to this review. All searches were conducted for articles published through May 2005. Data from included articles for each of the risk factor groups, smoking, diabetes, and periodontitis, were abstracted and analyzed. Results: A detailed search of the literature and evaluation of relevant articles identified 35 articles for inclusion in this systematic review. Nineteen articles were identified for smoking, 4 articles were identified for diabetes, and 13 articles were identified for periodontitis. One article met the criteria for both smoking and periodontitis. Implant survival and success rates were reported for smokers versus nonsmokers; diabetic patients versus nondiabetic patients; and patients with a history of treated periodontitis versus patients with no history of periodontitis. The findings revealed statistically significant differences in survival and success rates for smokers (better for nonsmokers), with greater differences observed when the data were analyzed according to bone quality (less for loose trabecular bone). No difference in implant survival rate was found between patients with and without diabetes. Likewise, no difference in implant survival rates was found between patients with a history of treated periodontitis compared to patients with no history of periodontitis. Conclusions: The results of this systematic review of the literature demonstrated that smoking has an adverse affect on implant survival and success. The effect of smoking on implant survival appeared to be more pronounced in areas of loose trabecular bone. Type 2 diabetes may have an adverse effect on implant survival rates, but the limited number of studies included in this review do not permit a definitive conclusion. A history of treated periodontitis does not appear to adversely affect implant survival rates but it may have a negative influence on implant success rates, particularly over longer periods. Keywords: dental implants, dental implant survival, diabetes, periodontitis, smoking, tobacco

Purpose: To systematically review the current literature on the clinical outcomes and incidence of complications associated with immediate implants (implants placed into extraction sockets at the same surgery that the tooth is removed) and early implants (implants placed following soft tissue healing). Materials and Methods: A Medline search was conducted for English papers on immediate/early placement of implants based on a series of search terms. Prospective as well as retrospective studies (randomized/nonrandomized clinical trials, cohort studies, case control studies, and case reports) were considered, as long as the follow-up period was at least 1 year of loading and at least 8 patients and/or at least 10 implants had been examined. Screening and data abstraction were performed independently by 3 reviewers. The types of complications assessed were implant loss; marginal bone loss; soft tissue complications, including peri-implantitis; and esthetics. Results: The initial search provided 351 abstracts, of which 146 were selected for full-text analysis. Finally, 17 prospective and 17 retrospective studies were identified, with observation times generally between 1 and 2 years for the prospective studies and around 5 years for the retrospective studies. The heterogeneity of the studies (including postextraction defect characteristics, surgical technique with or without membrane and/or bone substitute, implant location in socket, inclusion and exclusion criteria, and prosthetic rehabilitation), however, rendered a meta-analysis impossible. Most papers contained only data on implant loss and did not provide useful information on failing implants or on hard and soft tissue changes. In general, the implant loss remained below 5% for both immediate and early placed implants (range, 0% to 40% for immediate implants and 0% to 9% for early placed implants), with a tendency toward higher losses when implants were also immediately loaded. Conclusion: Because of the lack of long-term data, questions regarding whether peri-implant health, prosthesis stability, degree of bone loss, and esthetic outcome of immediate or early placed implants are comparable with implants placed in healed sites remain unanswered. Keywords: dental implants, early placement, extraction, immediate placement, osseointegration, partial edentulism, periodontology