Analysis of implant-failure predictors in the posterior maxilla: a retrospective study of 1395 implants

The aim of this study was to analyze predictors for dental implant failure in the posterior maxilla. A database was created to include patients being treated with dental implants posterior to the maxillary cuspids. Independent variables thought to be predictive of potential implant failure included (1) sinus elevation, (2) implant length, (3) implant diameter, (4) indication, (5) implant region, (6) timepoint of implant placement, (7) one-vs. two-stage augmentation, and (8) healing mode. Cox regression analysis was used to evaluate the influence of predictors 1-3 on implant failure as dependent variable. The predictors 4-9 were analyzed strictly descriptively. The final database included 592 patients with 1395 implants. The overall 1- and 5-year implant survival rates were 94.8% and 88.6%, respectively. The survival rates for sinus elevation vs. placement into native bone were 94.4% and 95.4%, respectively (p = 0.33). The survival rates for the short (<10 mm), the middle (10-13 mm) and the long implants (>13 mm) were 100%, 89% and 76.8%, respectively (middle-vs. long implants p = 0.62). The implant survival rates for the small- (<3.6 mm), the middle- (3.6-4.5 mm) and the wide diameter implants (>4.5 mm) were 92.5%, 87.9% and 89.6%, respectively (p = 0.0425). None of the parameters evaluated were identified as predictor of implant failure in the posterior maxilla.