Impact of Membrane Thickening and Perforation on Graft Remodeling After Osteotome Sinus Elevation: A Retrospective Study

ABSTRACT Introduction This study investigated the impact of sinus membrane thickening and perforation on graft remodeling following osteotome sinus floor elevation (OSFE). Materials and Methods A total of 136 patients who received single implants with simultaneous OSFE were retrospectively analyzed and categorized based on preoperative sinus membrane thickness: membrane thickening (MT; > 2 mm, n = 38) and normal thickness (NT; ≤ 2 mm, n = 98). Cone‐beam computed tomography was used to assess residual bone height and membrane thickness. Periapical radiographs obtained immediately postoperatively (T1) and at final follow‐up (T2) were used to quantify sinus bone gain and apical graft height. The incidence of membrane perforation and implant survival was also documented. Results Implant survival rates were comparable between groups (MT: 97.4%, NT: 99.0%, p = 0.485 ). The incidence of membrane perforation occurred significantly more frequently in the MT group than in the NT group (21.1% vs. 6.1%, p = 0.010 ). Although final sinus bone gain was similar, apical graft resorption was significantly greater in the MT group compared to the NT group (2.3 ± 0.4 mm vs. 1.8 ± 0.6 mm; p < 0.001 ), resulting in a higher incidence of complete apical bone coverage loss (39.5% vs. 16.3%, p = 0.004 ). Furthermore, membrane perforation increased apical graft resorption risk regardless of membrane thickness. Conclusions Sinus membrane thickening is associated with increased risk of perforation and greater apical graft resorption following OSFE. Thorough preoperative evaluation and careful surgical technique are essential to optimize outcomes, particularly in cases with thickened membranes.