Comparison of regional soft tissue changes after bimaxillary rotational surgery between class III deformity with overbite and open bite: A 3D imaging analysis

Background: This prospective study aimed to compare regional soft tissue changes between patients with class III overbite and open bite deformities treated with bimaxillary surgery involving clockwise and counter-clockwise mandibular setback, respectively.Material and methods: Class III deformity adults receiving Le Fort I and bilateral sagittal split osteotomies were grouped according to the incisal occlusion: overbite (n = 30) and open bite (n = 30). Combined cone-beam CT scans and 3D facial photographs preoperative and at least 1-year postoperative were taken to assess the soft tissue changes.Results: Postoperative changes for the overbite and open bite groups included anterior repositioning of nose (-0.8 +/- 1.2 mm and -1.1 +/- 1.1 mm, respectively) and cheek (-1.9 +/- 1.3 mm and -1.7 +/- 2.6 mm, respectively), posterior repositioning of chin (5.2 +/- 4.0 mm and 4.9 +/- 3.2 mm, respectively), and medial (-1.7 +/- 2.0 mm and -1.9 +/- 2.1 mm, respectively) and posterior (2.7 +/- 1.4 mm and 2.8 +/- 2.3 mm, respectively) repositioning of bilateral angles. Posterior (1.2 +/- 2.0 mm and 5.1 +/- 3.3 mm) and inferior (-1.4 +/- 2.2 mm and -2.4 +/- 2.7 mm) repositioning of upper lip and lower lip occurred in overbite group. Inferior (-2.3 +/- 2.4 mm) and superior (3.7 +/- 3.4 mm) repositioning of chin occurred in the overbite and open bite groups, respectively. Conclusions: Treatment of class III overbite and open bite deformities with bimaxillary rotational surgery resulted in comparable regional soft tissue changes, except for upper lip, lower lip and chin.