The International Journal of Oral & Maxillofacial Implants, Supplement/2009

Purpose: To evaluate whether systemic diseases with/without systemic medication increase the risk of implant failure and therefore diminish success and survival rates of dental implants. Materials and Methods: A MEDLINE search was undertaken to find human studies reporting implant survival in subjects treated with osseointegrated dental implants who were diagnosed with at least one of 12 systemic diseases. Results: For most conditions, no studies comparing patients with and without the condition in a controlled setting were found. For most systemic diseases there are only case reports or case series demonstrating that implant placement, integration, and function are possible in affected patients. For diabetes, heterogeneity of the material and the method of reporting data precluded a formal meta-analysis. No unequivocal tendency for subjects with diabetes to have higher failure rates emerged. The data from papers reporting on osteoporotic patients were also heterogeneous. The evidence for an association between osteoporosis and implant failure was low. Nevertheless, some reports now tend to focus on the medication used in osteoporotic patients, with oral bisphosphonates considered a potential risk factor for osteonecrosis of the jaws, rather than osteoporosis as a risk factor for implant success and survival on its own. Conclusions: The level of evidence indicative of absolute and relative contraindications for implant therapy due to systemic diseases is low. Studies comparing patients with and without the condition in a controlled setting are sparse. Especially for patients with manifest osteoporosis under an oral regime of bisphosphonates, prospective controlled studies are urgently needed. Keywords: bisphosphonates, diabetes, implant failure, osseointegration, osteoporosis, systemic disease

Purpose: The aim of this review was to determine the effect of several potential local risk factors on implant survival and success (primary outcomes) as well as on mucosal recession, bleeding on probing, and proximal marginal bone loss (secondary outcomes). Materials and Methods: A comprehensive review of the literature was conducted. The selection of publications reporting on human clinical studies was based on predetermined inclusion criteria and was agreed upon by three reviewers. After title and abstract screening of 2,681 publications obtained from the search, 19 articles were deemed to be relevant to the topic and the search criteria. Results: Limited data show that when an implant is placed within 3 mm of the neighboring tooth, proximal bone is at risk. The data regarding the placement of implants into infected sites are still insufficient, but studies have shown that this may be possible. Soft tissue thickness has not been shown to be a risk factor in implant survival. There is also no evidence to support a relationship between the width of keratinized tissue and implant survival. No studies were found that directly related bone density to implant survival. Implant stability was also difficult to examine due to the lack of validated stability measures. Discussion and Conclusion: One critical factor that faced the group during the review of the literature and interpretation of the data was the multifactorial nature of implant therapy. This makes isolation of specific risk factors difficult. Conclusions are limited by the current lack of quality clinical trials in this area. Keywords: dental implants, hard tissue, infection, interdental space, local risk factors, soft tissue

Purpose: The aim of this review was to evaluate a history of treated periodontitis and smoking, both alone and combined, as risk factors for adverse dental implant outcomes. Materials and Methods: A literature search of MEDLINE (Ovid) and EMBASE from January 1, 1966, to June 30, 2008, was performed, and the outcome variables implant survival, implant success, occurrence of peri-implantitis and marginal bone loss were evaluated. Results: Considerable heterogeneity in study design was found, and few studies accounted for confounding variables. For patients with a history of treated periodontitis, the majority of studies reported implant survival rates > 90%. Three cohort studies showed a higher risk of peri-implantitis in patients with a history of treated periodontitis compared with those without a history of periodontitis (reported odds ratios from 3.1 to 4.7). In three of four systematic reviews, smoking was found to be a significant risk for adverse implant outcome. While the majority of studies reported implant survival rates ranging from 80% to 96% in smokers, most studies found statistically significantly lower survival rates than for nonsmokers. Conclusions: There is an increased risk of peri-implantitis in smokers compared with nonsmokers (reported odds ratios from 3.6 to 4.6). The combination of a history of treated periodontitis and smoking increases the risk of implant failure and peri-implant bone loss. Keywords: implant success, implant survival, peri-implantitis, periodontitis, smoking, tobacco

Purpose: To systematically appraise the impact of mechanical/technical risk factors on implant-supported reconstructions. Material and Methods: A MEDLINE (PubMed) database search from 1966 to April 2008 was conducted. The search strategy was a combination of MeSH terms and the key words: design, dental implant(s), risk, prosthodontics, fixed prosthodontics, fixed partial denture(s), fixed dental prosthesis (FDP), fixed reconstruction(s), oral rehabilitation, bridge(s), removable partial denture(s), overdenture(s). Randomized controlled trials, controlled trials, and prospective and retrospective cohort studies with a mean follow-up of at least 4 years were included. The material evaluated in each study had to include cases with/without exposure to the risk factor. Results: From 3,568 articles, 111 were selected for full text analysis. Of the 111 articles, 33 were included for data extraction after grouping the outcomes into 10 risk factors: type of retentive elements supporting overdentures, presence of cantilever extension(s), cemented versus screw-retained FDPs, angled/angulated abutments, bruxism, crown/implant ratio, length of the suprastructure, prosthetic materials, number of implants supporting an FDP, and history of mechanical/technical complications. Conclusions: The absence of a metal framework in overdentures, the presence of cantilever extension(s) > 15 mm and of bruxism, the length of the reconstruction, and a history of repeated complications were associated with increased mechanical/technical complications. The type of retention, the presence of angled abutments, the crown-implant ratio, and the number of implants supporting an FDP were not associated with increased mechanical/technical complications. None of the mechanical/technical risk factors had an impact on implant survival and success rates. Keywords: clinical studies, oral implants, prosthodontics, risk factors

Purpose: To assess the literature on accuracy and clinical performance of computer technology applications in surgical implant dentistry. Materials and Methods: Electronic and manual literature searches were conducted to collect information about (1) the accuracy and (2) clinical performance of computer-assisted implant systems. Meta-regression analysis was performed for summarizing the accuracy studies. Failure/complication rates were analyzed using random-effects Poisson regression models to obtain summary estimates of 12-month proportions. Results: Twenty-nine different image guidance systems were included. From 2,827 articles, 13 clinical and 19 accuracy studies were included in this systematic review. The meta-analysis of the accuracy (19 clinical and preclinical studies) revealed a total mean error of 0.74 mm (maximum of 4.5 mm) at the entry point in the bone and 0.85 mm at the apex (maximum of 7.1 mm). For the 5 included clinical studies (total of 506 implants) using computer-assisted implant dentistry, the mean failure rate was 3.36% (0% to 8.45%) after an observation period of at least 12 months. In 4.6% of the treated cases, intraoperative complications were reported; these included limited interocclusal distances to perform guided implant placement, limited primary implant stability, or need for additional grafting procedures. Conclusion: Differing levels and quantity of evidence were available for computer-assisted implant placement, revealing high implant survival rates after only 12 months of observation in different indications and a reasonable level of accuracy. However, future long-term clinical data are necessary to identify clinical indications and to justify additional radiation doses, effort, and costs associated with computer-assisted implant surgery. Keywords: computer-assisted implant dentistry, dental implants, navigation

Purpose: The aim of this systematic review was to evaluate the existing scientific evidence on human clinical studies describing the application of computer-aided design/computer-assisted manufacturing (CAD/CAM) technology in restorative implant dentistry. Materials and Methods: Electronic searches for clinical studies from 1966 through May 2008 focusing on long-term follow-up were performed using the PubMed search engine. Concentrating on the restorative aspect of the CAD/CAM technology applicable to implant dentistry, pertinent literature was divided into articles related to implant abutments and implant frameworks. Results: Of the 885 articles initially reviewed, 5 articles (3 CAD/CAM framework and 2 CAD/CAM abutment) satisfied the search criteria of the literature search performed. Combining the results from the framework clinical trial studies, there were a total of 189 prostheses supported by 888 implants. The follow-up varied between 12 and 60 months. Four implants were lost prior to the insertion of the prosthesis and 46 after the insertion. One prosthesis failure was reported. Similarly, in the 2 abutment clinical trial studies there were a total of 53 ceramic abutments supported by 53 implants. The patients were followed between 12 and 44 months. No significant failures or complications were reported in association with the implants and their restorations. Conclusions: Based on a systematic review of literature concerning CAD/CAM used for fabrication of frameworks and abutments, preliminary proof of concept was established. Clinical studies on the use of these techniques were too preliminary and underpowered to provide meaningful conclusions regarding the performance of these abutments/frameworks. Keywords: CAD/CAM, implant dentistry, implant-supported abutment, implant-supported framework

Purpose: The aim of this article was to review the current literature with regard to the efficacy and effectiveness of flapless surgery for endosseous dental implants. The available data were evaluated for short- and long-term outcomes. Materials and Methods: A MEDLINE search was conducted on studies published between 1966 and 2008. For the purpose of this review, only clinical (human) studies with five or more subjects were included, and clinical opinion papers were excluded. Clinical studies or reports were further rated in terms of the level or weight of evidence using criteria defined by the Oxford Center for Evidence-Based Medicine in 2001. Results: The available data on flapless technique indicate high implant survival overall. The prospective cohort studies demonstrated approximately 98.6% (95% CI: 97.6 to 99.6) survival, suggesting clinical efficacy, while the retrospective studies or case series demonstrated 95.9% (95% CI: 94.8 to 97.0) survival, suggesting effective treatment. Six studies reported mean radiographic alveolar bone loss ranging from 0.7 to 2.6 mm after 1 year of implant placement. Intraoperative complications were reported in four studies, and these included perforation of the buccal or lingual bony plate. Overall, the incidence of intraoperative complications was 3.8% of reported surgical procedures. Conclusion: Flapless surgery appears to be a plausible treatment modality for implant placement, demonstrating both efficacy and clinical effectiveness. However, these data are derived from short-term studies with a mean interval of 19 months, and a successful outcome with this technique is dependent on advanced imaging, clinical training, and surgical judgment. Keywords: dental implants, flapless surgery, implant complications, implant success, literature review, meta-analysis

Purpose: The objective of this systematic review was to present the current scientific and clinical evidence related to implant-supported rehabilitations for the edentulous mandible and maxilla. Materials and Methods: An electronic search of several databases covered the period from January 1966 to August 2008. From a total of 2,371 publications identified from this search, 61 articles fulfilled the inclusion criteria set forth by the authors. It should be noted that only studies reporting on implants with rough surfaces were included in the final selection for this review. Results: Selected studies yielded data from 2,278 patients and 9,701 implants. Studies were grouped according to treatment protocol and prosthodontic design, and results on conventional, early, and immediate loading were assessed separately for fixed and removable dental prostheses. Clinical recommendations for implant loading in different edentulous indications were established using a special validation protocol of the published scientific and clinical evidence for different treatment modalities, which was based on the study design, sample size, and outcome homogeneity between studies. Conclusions: The highest level of scientific and clinical validation was found for conventional loading with mandibular overdentures and maxillary fixed dental prostheses. Insufficient scientific or clinical documentation/validation was found for immediate loading of maxillary overdentures, as well as for immediate loading of immediately placed implants combined with fixed or removable dental prostheses in either jaw. All other loading protocols for edentulous arches showed different degrees of clinical documentation. Keywords: dental implants, edentulism, fixed dental prosthesis, loading protocol, mandible, maxilla, removable prosthesis, systematic review

Purpose: To evaluate early and immediate loading of implants in the posterior maxilla and to investigate whether there is a difference in success rates, survival rates, and peri-implant parameters, including marginal bone level changes. Materials and Methods: A comprehensive systematic review of the literature was conducted. The selection of publications reporting on human clinical studies was based on predetermined inclusion criteria and was agreed upon by two reviewers. Results: Twelve papers were identified on early loading (two randomized controlled clinical trials [RCTs] and 10 prospective case series studies). Six papers were found on immediate loading (one RCT, four prospective case series, and one retrospective study). Conclusions: Under certain circumstances it is possible to successfully load dental implants in the posterior maxilla early or immediately after their placement in selected patients. The success rate appears to be technique sensitive, although no study has directly assessed this. A high degree of primary implant stability (high value of insertion torque) and implant surface characteristics play an important role. It is not possible to draw evidence-based conclusions concerning contraindications, threshold values for implant stability, bone quality and quantity needed, or impact of occlusal loading forces. As for the impact of the surgical technique on implant outcome in different bone densities, no studies prove significant superior results with one technique over another. Well-designed RCTs with a large number of patients are necessary to make early/immediate loading protocols in posterior maxilla evidence based, but ethical and practical considerations may limit the real possibility of such studies in the near future. Keywords: dental implants, fixed dental prostheses, loading protocol, partial edentulism, posterior maxilla, single crown, systematic review

Purpose: To evaluate the predictability of early and immediate loading protocols of implants in the posterior mandible and to investigate whether there is a difference in success rates, survival rates, and peri-implant parameters, including marginal bone level changes, between loading protocols. Materials and Methods: A comprehensive systematic review of the literature was conducted. The selection of publications reporting on human clinical studies was based on predetermined inclusion criteria and was agreed upon by two reviewers. Results: A total of 19 papers were selected: 8 on early loading, 9 addressing immediate loading, and 2 comparing immediate and early loading. Of the 19 studies, 5 were randomized clinical trials and 14 were prospective studies. Conclusions: Existing literature supports the early loading of microroughened dental implants in the partially edentulous posterior mandible at 6 to 8 weeks in the absence of modifying factors. Therefore, loading within this time frame can be considered routine for the majority of clinical situations in the posterior mandible, either with single crowns or fixed dental prostheses. Immediate loading of microroughened dental implants in the partially edentulous posterior mandible proved to be a viable treatment alternative. Caution is necessary when interpreting published outcomes for immediate loading, as the inclusion exclusion criteria are inconsistent and many subjective confounding factors are evident. Additional studies with longer follow-ups, specifically randomized clinical trials, are needed to consolidate the data for immediate loading. Priority should be given to trials testing immediate loading. Keywords: dental implants, fixed dental prostheses, loading protocol, partial edentulism, posterior mandible, single crown, systematic review

Purpose: The scientific evidence related to different or novel implant loading (primary objective) and directly associated implant placement (secondary objective) protocols developed for the anterior maxillae of partially edentulous patients was reviewed. Materials and Methods: A comprehensive search of electronic databases and a hand search of six relevant journals was performed. The principal outcome variables were implant survival, implant success, and esthetic appearance. Concerning esthetic treatment outcomes, articles were specifically screened for the presence of objective evaluation parameters and patient satisfaction assessment. Results: The analysis of the literature on immediately restored or conventionally loaded implants in the esthetic zone revealed an initial survival rate of 97.3% after 1 year (10 prospective cohort studies and one case series). For periods of 1 to 5 years, the survival rate was 96.7%. These survival rates are consistent with previous reports on more traditional loading modalities. However, for immediately placed implants with immediate restoration and occlusal loading, the survival rate dropped by approximately 10% (four studies). Success criteria such as stable crestal bone levels, soft tissue recession, and probing depth could not be evaluated on the basis of the available literature. Conclusion: There is a paucity of prospective cohort studies addressing patient-centered outcomes. No parameters specific to immediate loading protocols were available for evaluation. In order to validate or reject such implant protocols for use in the esthetically sensitive anterior maxilla, long-term clinical trials should routinely include objective esthetic criteria that comprehensively embrace the pertinent elements of "pink and white esthetics" in the form of readily used indices. Keywords: anterior mandible, anterior maxilla, dental implants, esthetics, fixed dental prostheses, loading protocol, partial edentulism, single crown, systematic review

Purpose: The aim of this review was to evaluate the clinical outcomes for the different time points of implant placement following tooth extraction. Materials and Methods: A PubMed search and a hand search of selected journals were performed to identify clinical studies published in English that reported on outcomes of implants in postextraction sites. Only studies that included 10 or more patients were accepted. For implant success/survival outcomes, only studies with a mean follow-up period of at least 12 months from the time of implant placement were included. The following outcomes were identified: (1) change in peri-implant defect dimension, (2) implant survival and success, and (3) esthetic outcomes. Results and Conclusions: Of 1,107 abstracts and 170 full-text articles considered, 91 studies met the inclusion criteria for this review. Bone augmentation procedures are effective in promoting bone fill and defect resolution at implants in postextraction sites, and are more successful with immediate (type 1) and early placement (type 2 and type 3) than with late placement (type 4). The majority of studies reported survival rates of over 95%. Similar survival rates were observed for immediate (type 1) and early (type 2) placement. Recession of the facial mucosal margin is common with immediate (type 1) placement. Risk indicators included a thin tissue biotype, a facial malposition of the implant, and a thin or damaged facial bone wall. Early implant placement (type 2 and type 3) is associated with a lower frequency of mucosal recession compared to immediate placement (type 1). Keywords: bone grafts, early implant placement, esthetics, immediate implant, implant survival

Purpose: The objective of this review was to evaluate the efficacy of different grafting protocols for the augmentation of localized alveolar ridge defects. Materials and Methods: A MEDLINE search and an additional hand search of selected journals were performed to identify all levels of clinical evidence except expert opinions. Any publication written in English and including 10 or more patients with at least 12 months of follow-up after loading of the implants was eligible for this review. The results were categorized according to the presenting defect type: (1) dehiscence and fenestration-type defects, (2) horizontal ridge augmentations, (3) vertical ridge augmentations, and (4) maxillary sinus floor elevations using the lateral window technique or transalveolar approach. The review focused on: (1) the outcome of the individual grafting protocols and (2) survival rates of implants placed in the augmented bone. Results and Conclusion: Based on 2,006 abstracts, 424 full-text articles were evaluated, of which 108 were included. Eleven studies were randomized controlled clinical trials. The majority were prospective or retrospective studies including a limited number of patients and short observation periods. The heterogeneity of the available data did not allow identifying one superior grafting protocol for any of the osseous defect types under investigation. However, a series of grafting materials can be considered well-documented for different indications based on this review. There is a high level of evidence (level A to B) to support that survival rates of implants placed in augmented bone are comparable to rates of implants placed in pristine bone. Keywords: bone grafting, bone-substitute material, dental implant, ridge augmentation, sinus floor elevation

Purpose: This review evaluated (1) the success of different surgical techniques for the reconstruction of edentulous deficient alveolar ridges and (2) the survival/success rates of implants placed in the augmented areas. Materials and Methods: Clinical investigations published in English involving more than 10 consecutively treated patients and mean follow-up of at least 12 months after commencement of prosthetic loading were included. The following procedures were considered: onlay bone grafts, sinus floor elevation via a lateral approach, Le Fort I osteotomy with interpositional grafts, split ridge/ridge expansion techniques, and alveolar distraction osteogenesis. Full-text articles were identified using computerized and hand searches by key words. Success and related morbidity of augmentation procedures and survival/success rates of implants placed in the augmented sites were analyzed. Results and Conclusion: A wide range of surgical procedures were identified. However, it was difficult to demonstrate that one surgical procedure offered better outcomes than another. Moreover, it is not yet known if some surgical procedures, eg, reconstruction of atrophic edentulous mandibles with onlay autogenous bone grafts or maxillary sinus grafting procedures in case of limited/moderate sinus pneumatization, improve long-term implant survival. Every surgical procedure presents advantages and disadvantages. Priority should be given to those procedures which are simpler and less invasive, involve less risk of complications, and reach their goals within the shortest time frame. The main limit encountered in this literature review was the overall poor methodological quality of the published articles. Larger well-designed long-term trials are needed. Keywords: alveolar bone loss, alveolar ridge augmentation, atrophy, autogenous bone, graft material, oral implant

Purpose: The aim of this review was to evaluate the techniques and outcomes of postextraction ridge preservation and the efficacy of these procedures in relation to subsequent implant placement. Materials and Methods: A MEDLINE/PubMed search was conducted and the bibliographies of reviews from 1999 to March 2008 were assessed for appropriate studies. Randomized clinical trials, controlled clinical trials, and prospective/retrospective studies with a minimum of five patients were included. Results: A total of 135 abstracts were identified, from which 53 full-text articles were further examined, leading to 37 human studies that fulfilled the search criteria. Many different techniques, methodologies, durations, and materials were presented in the publications reviewed, making direct comparison difficult. Conclusions: Despite the heterogeneity of the studies, it was concluded that ridge preservation procedures are effective in limiting horizontal and vertical ridge alterations in postextraction sites. There is no evidence to support the superiority of one technique over another. There is also no conclusive evidence that ridge preservation procedures improve the ability to place implants. Keywords: dental implants, extraction, grafting, ridge preservation, socket