Machine learning-based assessment of condylar changes after orthognathic surgery of asymmetric dentofacial deformities.

Introduction: This retrospective study aimed to investigate three-dimensional (3D) condyle change including volumetric, positional, rotational alterations in patients with asymmetric dentofacial deformities immediate and long after bimaxillary orthognathic surgery. Methods: The sample included 36 patients who underwent bimaxillary orthognathic surgery, with a maxillomandibular dental midline deviation >3 mm, excluding those with class II/III malocclusions and craniofacial syndrome. A fully automated deep learning-based assessment method was used to analyze the volume, position and rotation of condyle based on Cone-beam Computed Tomography (CBCT) images. Repeated measures ANOVA was used to compared the changes at three intervals-pre-surgery (T0), one-week post-surgery (T1), and six months post-surgery (T2)-of the deviated sides and non-deviated sides condyle. Results: The condyle on the deviated side was smaller than that on the non-deviated side, with significant volume reductions observed six months post-surgery on the deviated side. Several condylar changes were observed immediately after surgery, though of small magnitude, and it mostly tended to return to their original positions 6 months after surgery. However, the condyle rotated laterally on the deviated side and medially on the non-deviated side post operation and in long-term. Conclusion: For patients with asymmetry, condyle on the deviated side undergo greater remodeling than the non-deviated side after orthognathic surgery. There are measurable rotations in the coronal plane of condyle on both sides.