Three-Dimensional Evaluation of Implant Positioning in the Maxillary Sinus Septum: A Retrospective Study

Background: The aim of this study was to simulate implant placement in the maxillary sinus septum, as a potential alternative site to avoid sinus grafting. Material/Methods: One hundred partially or completely edentulous patients, with their maxillary sinus septum present in the edentulous region, were selected from the database of the Department of Maxillofacial Surgery, Cliniques Universitaires Saint Luc, Bruxelles, Belgium. Three-dimensional (3D) reconstructions were created using 3D planning software. 3D reconstructions were performed for each maxillary sinus. Using the software implant library, the implants that presented the best fit with the maxillary sinus septum and that followed the established inclusion criteria were selected. Results: All of the implants were inserted in premolar and molar regions. Most implants were inserted in the position of the second molar (21 of 55) or in the position of the first molar (17 of 55). In all sites the most frequently used implant was 4 mm in diameter and 7 mm in height. The mean coronal angle for the implant was 80.19 +/- 17.13 degrees and the mean sagittal angle was 94.83 +/- 9.94 degrees. The septal height represents 38.13% of the total available bone height (ABH). The mean percentage of the septum used to insert the implants was 47.33 +/- 2.47%. The septum increased the available bone height by a mean value of 2.18 +/- 1.47 mm. In 45 cases, the septa did not permit implant placement. Conclusions: In completely edentulous patients, inserting implants in sinus septa does not exclude the need for sinus grafting, but in partially edentulous patients, this minimally invasive technique is an alternative to subantral augmentation.