Identification of predictors for bone regeneration at the distal aspect of the second molar after impacted mandibular third-molar extraction

BACKGROUND: The authors evaluated predictive factors for alveolar bone regeneration at the distal aspect of the second molar after mandibular third-molar extraction. METHODS: Cone-beam computed tomography (CBCT) data from 146 patients (161 cases) who underwent horizontal or mesioangular impacted mandibular third-molar extractions were analyzed. Preoperative and postoperative scans using CBCT obtained at least 6 months apart were evaluated; the mean (SD) follow-up period was 37.3 (24.6) months. Multiple linear regression analysis was performed to determine predictors of bone regeneration. Multicollinearity was assessed and regression assumptions were verified via residual analysis. RESULTS: = 0.713; P < .001); all variance inflation factor values were less than 2.0, indicating no significant multicollinearity. The predictive equation is: Y (final depth) = 0.243 + 0.636 × X₁ (initial depth) + 0.045 × X₂ (age) - 0.676 × X₃ (ramus class). Cases with initial defects greater than 6 mm or from 5 through 6 mm combined with a ramus Class I had a higher likelihood of limited bone recovery (> 4 mm final defect depth). CONCLUSIONS: These findings emphasize the limited natural recovery of alveolar bone and the importance of initial defect depth, ramus class, and age in predicting outcomes and optimizing postoperative management. PRACTICAL IMPLICATIONS: Preoperative CBCT assessment of defect depth, ramus proximity, and patient age can help identify patients at risk of having limited bone regeneration.