Alveolar and maxillary sinus volumetric quantification after sinus lift, bone graft, and implant placement using cone-beam computed tomography: A retrospective study

Background: Tooth loss in the posterior maxilla frequently leads to alveolar ridge resorption and maxillary sinus pneumatization, compromising implant placement and often requiring sinus lift (SL) procedures. This study evaluated volumetric changes in the alveolar ridge and maxillary sinus using cone-beam computed tomography (CBCT) after SL, inorganic bovine bone grafting, and implant placement. Materials and Methods: A retrospective analysis was performed on 16 maxillary sinuses from 12 patients (6 female and 6 male; mean age: 55.8 years). CBCT scans were obtained at baseline (T0), postgraft evaluation before implant planning (T1), and postimplant healing (T2; mean follow-up 29 months). Alveolar ridge and sinus volumes were measured using ITK-SNAP software. The outcomes evaluated were alveolar ridge volume (mm 3 ), maxillary sinus volume (mm 3 ), percentage of bone gain (T1–T0), and graft resorption (T1–T2). Volumetric measurements at different time points were compared using analysis of variance; bone gain and resorption were compared using t -test, and clinical/demographic variables were assessed for associations. The significance level was P < 0.05. Results: A significant increase in alveolar ridge volume was observed at T1, followed by 11% resorption at T2 over 4 years, primarily in the cervical implant region. Maxillary sinus volume significantly decreased at T1 without subsequent re-pneumatization at T2. Sites with a volumetric gain exceeding 200% at T1 exhibited lower resorption rates at T2 ( P = 0.036). Clinical and demographic variables had no association with bone gain nor resorption ( P > 0.05). Conclusion: Bone gain and graft volume maintenance were primarily influenced by the extent of grafting, while patient-related variables showed no significant association.