International Journal of Oral Implantology, 01/2010

Background: Insufficient bone volume is a common problem encountered in the rehabilitation of the edentulous posterior maxillae with implant supported prostheses. Bone volume is limited by the presence of the maxillary sinus together with loss of alveolar bone height. Sinus lift procedures increase bone volume by augmenting the sinus cavity with autogenous bone and/or commercially available biomaterials. Objectives: To test whether and when augmentation of the maxillary sinus is necessary and which are the most effective augmentation techniques for rehabilitating patients with implant-supported prostheses. Search methods: The Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE were searched. Several dental journals were hand searched. The bibliographies of review articles were checked, and personal references were searched. More than 55 implant manufacturing companies were also contacted. The last electronic search was conducted on 7th January 2010. Selection criteria: Randomised controlled trials (RCTs) of different techniques and materials for augmenting the maxillary sinus for rehabilitation with dental implants reporting the outcome of implant therapy at least to abutment connection. Data collection and analysis: Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted independently and in duplicate. Authors were contacted for any missing information. Results were expressed as random-effects models using mean differences for continuous outcomes and odds ratios for dichotomous outcomes with 95% confidence intervals. The statistical unit of the analysis was the patient. Results: Ten RCTs out of 29 potentially eligible trials were suitable for inclusion. One trial including 15 patients, evaluated whether 5-mm-long implants with a diameter of 6 mm could be an alternative to sinus lift in bone having a residual height of 4 to 6 mm. Nine trials with 235 patients compared different sinus lift techniques and, of these, four trials (114 patients) evaluated the efficacy of platelet-rich plasma (PRP). Since different techniques were evaluated in different trials, only two meta-analyses evaluating the efficacy of PRP could be performed for implant failures (two trials) and complications (three trials). No statistically significant difference was observed for any of the evaluated interventions. Conclusions: Conclusions are based on few trials, usually underpowered, having short follow-ups, and often judged to be at high risk of bias, therefore they should be viewed as preliminary and interpreted with great caution. It is still unclear when sinus lift procedures are needed. Short implants (5 mm) can be successfully loaded in maxillary bone with a residual height of 4 to 6 mm, but their long-term prognosis is unknown. Elevating the sinus lining in the presence of 1 to 5 mm of residual bone height without the addition of a bone graft may be sufficient to regenerate new bone to allow rehabilitation with implant-supported prostheses. Bone substitutes might be successfully used as replacements for autogenous bone. If the residual alveolar bone height is 3 to 6 mm, a crestal approach to lifting the sinus lining and placing 8 mm implants may lead to less complications than a lateral window approach and placing implants at least 10 mm long. PRP treatment does not seem to improve the clinical outcome of sinus lift procedures with autogenous bone or bone substitutes. Keywords: bone augmentation, dental implant, randomised controlled clinical trial, sinus lift, systematic review Conflict-of-interest statement: Marco Esposito, Pietro Felice and Paul Coulthard are among the authors of four of the included trials, however, they were not involved in the quality assessment of these trials. This review is based on a Cochrane systematic review entitled 'Interventions for replacing missing teeth: augmentation procedures of the maxillary sinus' published in The Cochrane Library (see http:// www.cochrane.org/ for information). Cochrane systematic reviews are regularly updated to include new research and in response to comments and criticisms from readers. If you wish to comment on this review, please send your comments to the Cochrane website or to Marco Esposito. The Cochrane Library should be consulted for the most recent version of the review. The results of a Cochrane Review can be interpreted differently, depending on people's perspectives and circumstances. Please consider the conclusions presented carefully. They are the opinions of the review authors, and are not necessarily shared by the Cochrane Collaboration.

Objectives: To evaluate whether connective tissue grafts performed at implant placement could be effective in augmenting peri-implant soft tissues. Materials and methods: Ten partially edentulous patients requiring at least one single implant in the premolar or molar areas of both sides of the mandible were randomised to have one side augmented at implant placement with a connective soft tissue graft harvested from the palate or no augmentation. After 3 months of submerged healing, abutments were placed and within 1 month definitive crowns were permanently cemented. Outcome measures were implant success, any complications, peri-implant marginal bone level changes, patient satisfaction and preference, thickness of the soft tissues and aesthetics (pink aesthetic score) evaluated by an independent and blinded assessor 1 year after loading. Results: One year after loading, no patients dropped out, no implants failed and no complications occurred. Both groups lost statistically significant amounts of peri-implant bone 1 year after loading (0.8 mm in the grafted group and 0.6 mm in the non-grafted group), but there was no statistically significant difference between groups. Soft tissues at augmented sites were 1.3 mm thicker (P 0.001) and had a significantly better pink aesthetic score (P 0.001). Patients were highly satisfied (no statistically significant differences between treatments) though they preferred the aesthetics of the augmented sites (P = 0.031). However, five patients would not undergo the grafting procedure again and two were uncertain. Conclusions: Connective tissue grafts are effective in increasing soft tissue thickness, thus improving aesthetics. Longer follow-ups are needed to evaluate the stability of peri-implant tissues over time. Keywords: aesthetic, connective tissue graft, dental implant, soft tissue augmentation, randomised controlled clinical trial Conflict of interest: Nothing to declare.

Aim: To evaluate the treatment outcome of implant-supported single-tooth replacements performed by dental students as part of their undergraduate dental curriculum after a mean follow-up period of 10 years (range: 7.5 to 12 years). Materials and methods: A total of 51 patients were consecutively treated by dental students with 55 implants supporting single crowns. The treatment was performed under supervision of dentists and oral and maxillofacial surgeons, all with special knowledge about oral implantology. Survival of implant crown, survival of implant, probing depth, bleeding on probing and peri-implant marginal bone level change were evaluated at the end of the follow-up period. In addition, biological and technical complications during the entire follow-up period were assessed. Results: A total of 45 patients with 49 implants were available at the end of the study. The survival of the implant crowns as well as the implants was 94%. The mean probing depth at patient level was 4.8 mm. The probing depth varied between 2 and 10 mm at the individual site. The mean bleeding on probing score was 0.57 at patient level and absence of bleeding around all sites of the implants was rarely observed. The mean bone level change was -0.14 mm (range: 1.2 to -1.1 mm) during the first year of loading and 0.16 mm (range: 1.4 to -1.8) after 10 years at patient level. Five episodes of peri-implant inflammation due to excess cement were registered in five patients. Moreover, a fistula was observed at two implants in two patients. Finally, five technical complications occurred in five patients. Conclusions: Implant-supported single-tooth replacements performed by dental students as part of their undergraduate dental curriculum were characterised by high survival rates as well as few biological and technical complications. It seems acceptable to include implant therapy in the clinical undergraduate dental curriculum, provided a focus remains on straightforward cases with substantial supervision by trained dentists and oral and maxillofacial surgeons. Keywords: complications, dental implants, dental students, oral implants, retrospective study Source of support: The study was partially supported by Nobel Biocare, Denmark. Conflict of interest: None.

Purpose: To evaluate the success rate 1 year after loading of early loaded implants placed in vertically augmented bone using deproteinised bovine bone (Bio-Oss®) and a titanium-reinforced membrane (Gore-Tex®). Materials and methods: Twenty patients provided 25 sites that were treated with vertical guided tissue regeneration (GBR) using Bio-Oss and expanded polytetrafluoroethylene titanium-reinforced membranes. After 1 year of healing, the membranes were removed and 64 implants were placed (baseline) and loaded 30 days later. Standardised periapical radiographs were obtained at baseline and 1 year thereafter. One independent assessor clinically evaluated the amount of tissue regenerated and peri-implant bone level based on the radiographs. Outcome measures were prosthesis success, implant success, complications, amount of vertically regenerated bone, peri-implant marginal bone levels and histology. Results: No patient dropped out. A total of 23 out of 25 sites healed uneventfully. Two sites showed early membrane exposure. In these sites, the surgery was repeated with success 2 months later. Clinical evaluation showed a mean vertical bone defect of 5.6 mm (SD 1.7). Mean vertical bone gain after GBR was 5.2 mm (SD 1.5). The histology of five samples retrieved from four patients showed a total percentage of xenograft and new bone of 52.6%, with dispersed graft particles surrounded by layers of bone. All implants were stable after 1 year of function, yielding a survival rate of 100%. Statistically significant peri-implant bone loss (0.95 mm; SD 0.21; 95% confidence interval 0.85 to 1.05; P 0.001) was observed radiographically from baseline to the 1-year follow-up. Conclusions: This prospective cohort study shows that by using deproteinised bovine bone and a non-resorbable titanium-reinforced membrane, vertical bone gain can be obtained and implants can be loaded after 30 days. The vertical regenerated tissue exhibited good stability over 1 year of implant function. Keywords: bone regeneration, bone substitute, implants, membrane Conflict of interest: All materials used in this study were purchased by the author and it is therefore free of any commercial or institutional interest.

Aims: This 2-year prospective multi-centre study aimed to evaluate the survival of implants loaded 14 weeks after vertical ridge augmentation (VRA). Materials and methods: Twenty consecutive patients scheduled for VRA around implants were selected for this study in three private centres. Nano-structured Mg-enriched hydroxyapatite (Mg-e HAP) was used as the only augmentation filler material. It was covered with a titanium reinforced extended polytetrafluoroethylene (e-PTFE) membrane (Gore-Tex). A total of 42 rough-surface implants were inserted in the same surgical session. Healing abutments 2 mm long were used instead of cover screws to optimise aesthetics. All patients underwent a second surgery after 3 months. Thereafter, definitive restorations were seated within 2 weeks using a platform-switching concept. Outcome measures were amount of vertical bone gain, prosthesis and implant success, complications and radiographic marginal bone level changes assessed at 12 and 24 months of prosthetic loading. Frequency resonance analysis expressed using ISQ (implant stability quotient) values was performed at implant insertion (T0), when definitive restoration was seated (T1) and after 24 months of prosthetic loading (T2). Results: At the end of the study, no patient dropped out, all implants were clinically stable and no prosthesis failed. Initial clinical evaluations showed an average defect height of 4.1 mm. Only one late membrane exposure was registered. Complete bone filling of the regeneration volume was obtained in 19 out of 20 cases. The mean bone height gain was 5.6 mm. Radiographic assessments of inter-implant regenerated bone levels after 24 months of loading presented a mean value of 1.0 mm (SD 0.48 mm), stable compared to the same analysis at the 12-month follow-up. A statistically significant loss of peri-implant bone level occurred over time. Mean peri-implant bone levels were 0.3 mm at the time of prosthetic loading, 0.90 mm after 1 year and 0.98 after 2 years. ISQ values statistically significantly increased over time. At implant placement the mean ISQ value was 49.3, at delivery of the final restoration it was 63.9 and after 2 years of loading it was 73.6. Conclusion: This clinical study suggests that VRA around rough-surface implants using e-PTFE membrane and nano-structured Mg-e HAP can be successful even in cases with early loading. Keywords: barrier membranes, implant rough surface, nano-crystalline hydroxyapatite, platform switching, vertical ridge augmentation Conflict of interest: self-supported study, no conflict of interest to declare

Purpose: To present results of a survey on the status of implantology in Switzerland in 2006. Materials and methods: A questionnaire was sent to all SSO (Swiss Dental Society) members asking for personal (anonymous) background data and their implantology concepts. Specific questions dealt with level of recognition of implants, use of implants, superstructures, success and failure rates, recall and training. Results: A total of 1568 (47.3%) of the 3315 questionnaires were returned. Straumann, Nobel Biocare, 3i, SPI and Frialit were the most commonly used implant systems in Switzerland. Almost two-thirds (63.8%) of the dentists placed more than 20 implants per year. Long-term prognosis was the crucial factor, whereas material costs played a minor role. The edentulous mandible was the indication of choice, whereas the edentulous maxilla applied less. Almost every dentist active in implantology followed continuing educations programs in the field. Conclusions: Compared to a study undertaken 12 years ago, the number of dentists engaged in implantology doubled, meaning at least one-third of non-hospital dentists in Switzerland were involved in dental implantology. Overall, willingness to extend the therapeutic range has greatly increased. Keywords: implantology, status report, Switzerland