Evaluation of the Effects of Different Orthognathic Surgery Approaches on Mandibular Bone Structure Using Fractal Analysis

Background: In orthognathic surgery planning, two main approaches are commonly used: the conventional orthodontic–surgical (COS) approach and the surgery-first (SF) protocol. The aim of this study was to comparatively evaluate trabecular bone changes in the mandibular condylar, angular, and molar regions following COS and SF protocols using fractal analysis (FA). Methods: A total of 40 individuals (21 females, 19 males) who underwent bilateral sagittal split ramus osteotomy and Le Fort I osteotomy were included in the study. Patients were divided into COS and SF groups. Trabecular changes in the mandibular osteotomy line, condylar, and angular regions were evaluated on panoramic radiographs using FA, and fractal dimension values were calculated using the box-counting method. Results: No statistically significant differences were found between the groups in terms of baseline and post-treatment FA values in the molar and angular regions (p > 0.05). In contrast, a statistically significant difference was observed between the groups in the condylar region (p ≤ 0.05). The total treatment duration was significantly shorter in the SF group (p < 0.05). Conclusions: FA findings reveal that COS and SF protocols show similar effects in terms of mandibular bone healing, but the surgery-first approach is preferable due to its clinical advantages.