Investigating the relationship between the remodeling of TMJ bony structures and condylar rest position following orthognathic surgery in class II and class III skeletal malocclusions

Abstract

ObjectivesWe investigated the bone remodeling in the condyle and glenoid fossa after surgically corrected class II and class III dentoskeletal malocclusion patients and the relationship between these changes and the condylar rest position. MethodsA retrospective study was conducted based on the pre-operative and 1-year postoperative computed tomography (CT) scans of class II and class III skeletal malocclusion patients. Condylar remodeling was assessed by total volume change and surface distance between corresponding points in the regions of interest (ROI). Glenoid fossa remodeling was measured by the surface distance between the closest points in the ROI. The association between the remodeling of TMJ bony structures and the condylar position was tested by Spearman’s correlation. ResultsTwenty-one subjects with class II (17 females, 4 males) and twenty subjects with class III (13 females, 7 males) were recruited.The condylar volumes significantly decreased after surgery in class II malocclusion patients and significantly increased in class III malocclusion patients (p < 0.01). The condyle and glenoid fossa experienced remodeling of less than 1.5 mm and 1 mm respectively. Positional change of condyle at the jaw rest position had a weak correlation with condylar remodeling (p < 0.05, 0.2 ≤ |r| ≤0.4), but no association with the glenoid fossa remodeling (p > 0.05). ConclusionsThe volume of condyles changed significantly after orthognathic surgery in both groups. Both condyle and glenoid fossa experienced remodeling in class II and Class III patients. Those changes did not considerably influence the change of the condylar rest position.