Long-term survival of dental implants placed in the grafted maxillary sinus: systematic review and meta-analysis of treatment modalities.

BACKGROUND: A prevalent modality to increase the amount of available bone prior to implantation is grafting of the maxillary sinus. Multiple factors such as the surgical technique, moment of implant placement as well as grafting materials and membranes are known to affect implant survival. However, the role of different factor combinations and associated reciprocal effects remain unclear. Conventional statistical methods do not consider inconsistency of study designs and do not take covariables into account. Hence, a systematic research and meta-analysis was conducted to investigate the influence of various treatment modalities on implant survival in the grafted maxillary sinus. MATERIALS AND METHODS: A meta-analysis was conducted according to the PRISMA guidelines. Articles published from 1980 through January 2013 were electronically and manually searched in MEDLINE (Ovid), the Cochrane Register of Controlled Trials, the Database of Abstracts of Effects, and the Cochrane Database of Systematic Reviews. Clinical reports on single intervention sinus augmentation with root-form implants, a minimum of 10 patients and 6 months of loading were eligible for inclusion if implant survival was stated or calculable. Results were calculated by non-parametric univariate Kaplan-Meier analysis and Bayesian multivariate interval-censored Cox regression. RESULTS: A total of 122 publications on 16268 endosseous implants placed in grafted maxillary sinus were included. The treatment parameters surgical approach, grafting material and implant type showed no selective preference. However, application of membranes showed a significantly reduced hazard-ratio, independent of other co-factors. CONCLUSIONS: The use of membranes is the most significant factor to achieve long-term implant survival in sinus augmentation procedures. More data exceeding 3 years follow-up are needed to address prospective confounding and improve clinical evidence.

Sinus floor elevation using osteotomes: a systematic review and meta-analysis.

BACKGROUND: Various techniques of sinus floor elevation (SFE) are described. The elevation with osteotomes (OSFE) from a crestal approach is a relatively new technique. The aim of this systematic review and meta-analysis was to evaluate the clinical outcome of implants placed into the maxillary sinus augmented with an OSFE technique. METHODS: A systematic online and manual review of the literature identified articles dealing with OSFE. Applying rigid inclusion criteria, screening and data abstraction were performed independently by two reviewers. The follow-up of loaded implants was a minimum of 6 months. The identified articles were analyzed regarding implant outcome and defined surgical aspects. Survival and success rates were estimated by Kaplan-Meier curves. RESULTS: Eight out of 44 articles dealing with osteotome sinus floor elevation met the inclusion criteria. Five of the studies met established success criteria. The survival and success rates were 95.7% and 96.0% after 24 months and 36 months, respectively. The median and mean follow-up periods were 24 and 18.73 months for the survival rate and 24 and 19.7 months for the success rate. Regarding different surgical elements, i.e., osteotome techniques, implant types, and augmentation materials, the database was multivariate. Thus, no statistical analysis could be performed on these parameters. CONCLUSIONS: Short-term clinical success/survival (

Hard tissue reaction to dual acid-etched titanium implants: influence of plaque accumulation. A histological study in humans.

OBJECTIVES: The aim of this investigation was to evaluate histologically, histometrically, and histomorphometrically the influence of plaque accumulation on the peri-implant hard tissues. MATERIAL AND METHODS: Twelve fully edentulous subjects were selected for this investigation. Four to five standard titanium screw implants were placed interforaminally. Two small custom-made screw implants were incorporated in the region of the former first molar, one in each lower quadrant. One month after abutment connection, plaque control was terminated randomly at one of the custom-made implants and continued at the other implant. The custom-made implants and the surrounding tissue were harvested after different time points of plaque accumulation (7, 21, or 90 days). Thus, according to the plaque control program and implant removal time, there were six groups each with four implants for investigation. After histologic processing of the biopsies, histologic, histometric, and histomorphometric analyses were performed. RESULTS: Four of the 24 implants were unavailable for analysis. One implant was mobile at abutment connection and another implant was mobile 2 weeks after abutment connection; both implants had to be removed. The bone around two implants was destroyed during the removal with the trephine bur; therefore, these two implants could not be evaluated histologically either. No differences in the histologic appearance of the peri-implant bone between the different groups could be observed. Histomorphometrically, the implant surface in contact with mineralized bone as a fraction of the implant surface (measured from the buccal to the lingual implant shoulder) varied between 59% and 73%. The implant surface in contact with mineralized bone from the first bone-to-implant contact buccally to the first bone-to-implant contact lingually varied between 80.6% and 91.5%. The values for the distance from the implant shoulder to the first bone-to-implant contact, i.e. peri-implant bone loss, varied from 1.1 to 2.2 mm. No statistically significant differences could be found between any of the evaluated variables. CONCLUSIONS: This clinical investigation is the first to evaluate the hard tissue reactions to different plaque accumulation periods. Within the limits of this experiment, it can be concluded that the bone reaction toward the different plaque accumulation periods and in the different plaque control/accumulation groups were similar. It can be further concluded that the observed bone loss is rather attributed to the establishment of the biologic width than to plaque accumulation.