Prevalence and Morphology of the Palatal Bone Reservoir in the Posterior Maxilla as an Alternative to Maxillary Sinus Lift: A Cross-Sectional Retrospective Analysis Determined by Helical CT Scan

Background: Maxillary sinus lift is among the most common preprosthetic procedures in the posterior maxilla due to alveolar ridge resorption and the maxillary sinus pneumatization. It often extends treatment duration, significantly increases costs, and is not without complications. Objective: To explore the prevalence and morphology of the palatal bone reservoir as a viable site for dental implant insertion, offering a conservative alternative to avoid maxillary sinus lift. Methods: DICOM data sets from helical CT of maxillofacial trauma patients aged 50 years and older were used to perform virtual dental implant positioning in the edentulous second premolar, first molar, or second molar areas using ImplaStation software (version 5.3.2; ProDigiDent, Inc., Scottsdale, AZ, USA). A 3D Slicer software (version 5.3.2; ProDigiDent, Inc., Scottsdale, AZ, USA) was used to calculate the volume of the palatal bone reservoir and identify its mean density. The density of the residual alveolar process was also identified and compared with that of the previous one. Results: A total of 1822 maxillofacial trauma cases with helical CT between 2015 and 2025 were retrieved. After exclusion, 305 cases were analyzed. A total of 65 implants were virtually positioned in 50 patients. The mean volume of the palatal bone reservoir was 229 ± 139.2 mm3 with a mean radiodensity of 546.7 ± 159.6 HU. The mean radiodensity of the residual alveolar process was 286.3 ± 118.0 HU. The palatal bone reservoir was significantly denser than the residual alveolar process (95% CI [184.2, 336.6]; p < 0.01). Conclusions: The presence of a palatal bone reservoir is not uncommon and can offer a more conservative alternative for implant placement, potentially increasing primary stability and facilitating immediate loading.