Investigation of condylar changes in cone beam computed tomography imaging in orthognathic surgery patients

Background and Objective: Dentofacial deformities are clinically significant deviations of the maxillomandibular complex from its normal position, often resulting in occlusal disorders. Orthognathic surgery is widely used to correct occlusal disorders. This study aims to determine the impact of orthognathic surgery on the metric measurements of the mandibular condyle using cone-beam computed tomography (CBCT) imaging. Materials and Methods: This cross-sectional descriptive study was conducted at the Faculty of Dentistry, Tokat Gaziosmanpasa University, between 2013 and 2023. Fifty patients who had completed their skeletal growth and had undergone bilateral sagittal split ramus osteotomy and Le Fort I osteotomy under general anesthesia were included in the study. Demographic (age and gender) and clinical data (occlusion class [Class I, Class II, Class III], type and date of surgery, and maxillary and mandibular interventions [advancement, setback, lowering, rotation]) were collected. CBCT measurements were performed on preoperative and 6-12 month postoperative images. Linear, angular, and volumetric measurements were used to evaluate changes in the mandibular condyle. The association between demographic and clinical characteristics, preoperative and postoperative metric measurements, and the changes between pre and postoperative measurements were analyzed. Results: During the study period 31 females (62%) and 19 males (38%) were included in the study. Males were, on average, 4 years older than females with a statistically significant difference (p=0.011). Analysis of preoperative and postoperative CBCT data revealed no significant differences in right and left mandibular plane angle, right and left condyle depth, right and left condyle width, or right and left condyle length. The right axial condylar angle significantly increased from 19.0 preoperatively to 21.2 postoperatively. Similarly, the left axial condylar angle and left coronal condylar angle increased significantly from 16.5 and 82.2 preoperatively to 21.2 and 82.6 postoperatively. When condylar volume changes were analyzed by gender, both right and left condyle volume changes showed significant differences, with males exhibiting significantly lower right and left condyle volume changes than females. Conclusion: Different results were obtained when comparing preoperative and postoperative CBCT measurements. The effects of orthognathic surgery on condylar positioning involve various local factors, including the temporomandibular joint's (TMJ) complex structure and the remodeling and adaptation processes. Keywords: Dentofacial deformity, occlusal disorders, orthognathic surgery, cone-beam computed tomography.