Abstract
BACKGROUND: The surgical outcomes and stability of patients with skeletal Class II malocclusion determine the success of treatment. Variations in surgical interventions, patient responsiveness, and growth patterns across vertical facial morphologies result in varying treatment outcomes and postoperative stability. METHODS: This retrospective study recruited 52 adults diagnosed with skeletal Class II malocclusion treated with bimaxillary surgery; these adults were divided into two groups according to their vertical facial patterns. Cone-beam computed tomography images were collected before surgery (T0), after surgery (T1), and after orthodontic treatment (T2). Reconstructed three-dimensional images were used for cephalometric measurements and analysis. RESULTS: From T0 to T1, the Frankfort-mandibular plane angle decreased in the high-angle group but increased in the low-medium-angle group. The mandible advanced 9.02 and 6.21 mm in the high-angle and low-medium-angle groups, respectively. From T1 to T2, significant changes were observed in the anterior mandible horizontal movement of the high-angle group (-1.91 ± 3.63 mm) compared with the low-medium-angle group (-0.57 ± 1.04 mm). There were more patients exhibit clinically significant relapse (>2 mm) in the high-angle group (44 %) than in the low-medium-angle group (20 %). CONCLUSION: The relapse patterns in the two groups were similarly upward and backward. However, the high angle group exhibited greater average postoperative changes. The proportion of patients who exhibited a clinically significant relapse was higher in the high angle group.