Three-dimensional quantitative changes of condyle in patients with skeletal class III malocclusion after bimaxillary orthognathic surgery with 5-year follow-up.

Abstract

The present study aimed to characterize three-dimensional (3D) long-term quantitative condyle change including positional, surface, and volumetric alterations in patients with skeletal class III malocclusion treated with bimaxillary orthognathic surgery. Twenty-three eligible patients (9 males, 14 females, mean age: 28.28years old) treated from Jan. 2013 to Dec. 2016 with postoperative follow-up over 5years were retrospectively enrolled. Cone-beam computed tomography scan for each patient was conducted at 4 stages: 1week preoperatively (T0), immediately after surgery (T1), 12months postoperatively (T2), and 5-year postoperatively (T3). Positional changes, surface, and volumetric remodeling of condyle were measured in segmented visual 3D models and statistically compared between stages. Our 3D quantitative calibrations revealed that the condylar center shifted in anterior (0.23 ± 1.50mm), medial (0.34 ± 0.99), and superior (1.11 ± 1.10mm) directions and rotated outward (1.58 ± 3.11°), superior (1.83 ± 5.08°), and backward (4.79 ± 13.75°) from T1 to T3. With regard to condylar surface remodeling, bone formation was frequently observed in the anteromedial areas, while bone resorption was commonly detected in the anterolateral area. Moreover, condylar volume remained largely stable with a minimal reduction during the follow-up. Collectively, although condyle undergoes positional changes and bone remodeling after bimaxillary surgery in patients with mandibular prognathism, these changes largely fall in the range of physical adaptations in the long run. These findings advance the current understanding of long-term condylar remodeling after bimaxillary orthognathic surgery in skeletal class III patients.