Association Between the Mandibular Cortical Index on Panoramic Radiographs and Mandibular Condylar Alterations After Osteotomy.

PURPOSE: This study aimed to evaluate whether the mandibular cortical index (MCI) on panoramic radiographs is associated with condylar morphological changes following orthognathic surgery. MATERIALS AND METHODS: This retrospective study enrolled patients who underwent sagittal split ramus osteotomy (SSRO) or SSRO combined with Le Fort I osteotomy at our hospital. Preoperative panoramic radiography was performed to evaluate the MCI, and pre- and postoperative condylar morphology was assessed using computed tomography (CT). The primary outcome was the presence or absence of postoperative condylar morphological changes. An expanded multivariable logistic regression model including MCI, surgical procedure, age, sex, and operative time was evaluated. Given the limited number of outcome events and the collinearity identified in the expanded model, a reduced model including MCI and surgical procedure was used as the primary multivariable model. Statistical significance was set at P < 0.05. RESULTS: Overall, postoperative condylar morphological changes were observed in 19 patients, while 41 patients showed no such changes. In the SSRO-alone group (n = 40), a significant association was found between MCI and postoperative condylar morphological changes (P = 0.004). Among the 20 patients who underwent SSRO combined with Le Fort I osteotomy, postoperative condylar morphological changes were observed in 10 cases and absent in 10 cases. The association between MCI and postoperative condylar morphological changes did not reach statistical significance in this subgroup (P = 0.370). In the primary multivariable model including MCI and surgical procedure, MCI was significantly associated with postoperative condylar morphological changes (OR, 6.96; 95% CI, 1.97-24.58; P = 0.003). CONCLUSIONS: MCI assessed on panoramic radiographs was associated with postoperative condylar morphological changes following orthognathic surgery. However, given the limited sample size and potential residual confounding, these findings should be interpreted as exploratory.