Onlay augmentation versus sinuslift procedure in the treatment of the severely resorbed maxilla: a 5-year comparative longitudinal study

Augmentation procedures in the severely resorbed maxilla are standard techniques in preprosthetic surgery. Aim of the present study was to compare onlay bone grafting and sinus floor elevation with autogenous bone grafts in edentulous patients in terms of bone resorption of the posterior alveolar crest and implant survival in a 5-year longitudinal study. A total of 100 patients (53 female and 47 male patients) requiring augmentation using autogenous bone due to a severely resorbed maxillae were evaluated. The degree of resorption and bone quality were preoperatively estimated in panoramic radiographs according to Lekholm and Zarb. The overall 5-year success rate of implants placed after augmentation procedures in the posterior maxilla was 93.1%. Following onlay augmentations 215 out of 235 implant insertions were successful, i.e. a success rate of 91.5% was achieved. In the sinuslift group, 330 out 349 implants remained successful, i.e. a success rate of 94.6% was found. The difference between both groups was statistically significant at the end of the evaluation period. Bone resorption, measured as loss of total bone height in panoramic radiographs, was initially more pronounced following onlay augmentations (>20% after 12 months of observation). The degree of resorption decreased in the further course of the study. Lower resorption rates and a higher overall success rate were demonstrated for the sinus lift group.