Clinical evaluation of a modified maxillary sinus floor elevation technique with immediate implant placement: a retrospective study

The aim of this study was to evaluate the clinical effectiveness and reliability of an improved maxillary sinus floor elevation technique combined with immediate implant placement in patients with insufficient residual bone height in the posterior maxilla. A total of 64 edentulous patients with inadequate posterior maxillary bone height were enrolled. Among these patients, 34 underwent the improved maxillary sinus floor elevation technique with simultaneous implant placement, whereas 30 underwent the conventional bone chisel technique under the same surgical protocol. Radiological and clinical assessments were performed to comprehensively evaluate the effectiveness of the improved technique and to compare its osteogenic outcomes with those of the conventional method. The mean immediate increase in vertical bone height was significantly greater in the improved technique group (6.016 ± 1.312 mm) than in the bone chisel group (2.797 ± 0.898 mm; P < 0.001). Significant differences were also observed between the two groups in terms of apical bone coverage along the implant axis immediately postoperatively and at the 6–10 month follow-up (P < 0.001). Similarly, peri-implant bone coverage significantly increased in the improved technique group at both time points (P < 0.001). No significant differences were found in the short-term implant success or survival rates between the two groups. Notably, no intraoperative maxillary sinus membrane perforations occurred in the improved technique group, and postoperative complications were limited to mild swelling and pain at the surgical site. The improved maxillary sinus floor elevation technique yields favourable clinical outcomes in patients with severely resorbed posterior maxillae, particularly when the residual bone height is smaller than 5 mm. This technique constitutes a viable alternative to lateral window sinus augmentation for such cases.