Vertical skeletal and facial profile changes after surgical correction of mandibular prognathism

Background: Mandibular prognathism is often corrected by surgical orthodontics. Correction of the sagittal facial profile has received wide attention. However, vertical changes remained undefined and thus, were investigated. Methods: Subjects included 18 patients with mandibular prognathism who had surgical correction (S group, mean age: 20.1 ± 3.2 years) and 18 patients with Class I malocclusion (C group, mean age: 21.2 ± 3.6 years). Cephalograms were taken at the initial visit (T1) for both the groups and one year after surgery (T2) for the S group and analyzed by standard protocols. The vertical differences between the S and C groups at T1 and within the S group at T1 and T2 were compared. Additionally, the C group at T1 and the S group at T2 were compared. Results: Comparison between groups at T1 revealed no difference in the anterior and posterior upper facial heights (58 mm and 50 mm, respectively). However, the S group exhibited a longer anterior lower facial height and a shorter posterior lower facial height. Accordingly, any vertical measurements and comparisons related to the mandible revealed significant difference between groups. Surgical correction did not change the vertical chin position. Contrarily, the posterior ramus heights were reduced (from 54 to 50 mm). The vertical measurements and comparisons for soft tissues reflected those for hard tissues. Conclusions: The results indicate that through surgical correction of mandibular prognathism, vertical facial heights can be maintained within normal physiological function.