Implants inserted with graftless osteotome sinus floor elevation - A 5-year post-loading retrospective study

PURPOSE To report the outcome of graftless osteotome sinus floor elevation (OSFE) in order to evaluate whether apical bone gain depends on the initial residual bone height and whether the initial residual bone height has an influence on the amount of marginal bone loss. Furthermore the study aimed to assess if perforations of the Schneiderian membrane or residual bone height are potential predictors of implant survival. MATERIALS AND METHODS In this retrospective study all patients were included who were treated between 2001 and 2010 and received dental implants in combination with OSFE in a private practice. Patients having 1 to 11 mm of residual bone height were subjected to crestal sinus lift elevation. One hundred and thirteen patients with 233 implants were included in this study. The follow-up period was 5-years post-loading for all patients. The average initial bone level height was 5.9 ± 1.7 mm. No bone graft or substitute material was used. All implants healed transgingivally and were loaded 3 months after insertion. Outcome measures were prosthetic success, implant success, complications, radiographic crestal bone level changes and apical (sinus floor) bone height. RESULTS Sixty-three patients dropped out during the 5-year post-loading follow-up. Seven implants in 7 patients failed. Implant survival rate 5 years after loading was 93.8% at patient level. Implants succeeded in 92.7% of all cases. In six patients (5.3%), prostheses failed and had to be remade. Minor complications like small ceramic fractures and loosening of prosthetics were observed in seven patients (6.2%). Average marginal bone loss at 5 years of follow-up was 0.5 ± 0.8 mm per patient. No correlation was found between marginal bone loss and initial residual bone height. Average gained bone height was 4.5 ± 1.4 mm after 5 years of loading. We found a significantly negative linear correlation for apical bone gain depending on the baseline bone level (P < 0.001). The apical bone gain was higher in cases with less residual bone. CONCLUSIONS Implants after graftless osteotome sinus floor elevation showed excellent survival and success rates after 5 years of loading. Apical gain of newly formed bone was positively correlated with the initial bone height showing a statistical significance. However, initial residual bone height is also a predictor for implant survival, i.e. survival increases by 1.6 times with every additional millimetre of initial residual bone height. Conflict-of-interest statement: All authors declare that they have neither financial nor non-financial competing interests.