Long-term condylar dimensional changes in skeletal class III orthognathic surgery patients

To evaluate long-term condylar dimensional changes in skeletal Class III orthognathic surgery patients using cone beam computed tomography (CBCT). The sample was composed of 33 (27 females, 6 males) patients diagnosed with skeletal Class III dentofacial deformity, who underwent bimaxillary orthognathic surgery. The mean age of the patients at surgery was 22.7 ± 4.8 years. CBCT images were taken before surgery (mean 0.03 ± 0.2 years), after surgery (mean 1.1 ± 0.3 years) and at long-term follow-up (mean 4.5 ± 0.6 years). Three-dimensional (3D) condylar models were constructed from CBCT images utilizing threshold segmentation and manual editing. Volumetric measurements were performed to quantify condylar postoperative dimensional changes. To assess linear changes condylar surface color-coded distance maps were computed, and five regions of interest were selected for interpretation of condylar remodelling. Significant condylar volume change on average by 20.1 ± 73.8 mm³ (p = 0.036) was recorded 1 year after surgery. Condylar volume significantly increased on average by 32.0 ± 65.8 mm³ (p<0.001) between post-surgery and long-term follow up. Four years after surgery, the volume was not significantly different from the preoperative volume (p=0.408). Among the condylar remodelling signs, bone resorption showed a higher frequency than bone formation 4 years after surgery. However, the overall amount of remodeling did not exceed 0.5 mm in any of the regions of interest. Minor condylar dimensional changes were observed 4 years after bimaxillary orthognathic surgery in skeletal Class III patients.