Abstract: Objective: To evaluate changes and correlations of facial soft and hard tissues in skeletal Class III malocclusion patients after a combined orthodontic and orthognathic surgery treatment. Method: In this study, 32 patients with skeletal class III malocclusion received a combined orthodontic and surgical treatment. Cone-beam computed tomography (CBCT) was performed pre-(T1) and post-(T2) treatment. Lateral cephalometric radiographs were obtained from CBCT scans. Landmarks on the sagittal plane were selected to measure the angle, thickness and distance of the profile. Paired t-test was used to compare the angles and thicknesses, and Pearson linear correlation analysis was conducted to examine the correlation between soft and hard tissue variations. Results: There were significant angle differences in NLA, MLA, MP-SN and L1-SN (P< 0.05) with the exception of U1-SN (P >0.05). Soft tissue thickness TLL', TBs significantly increased (P < 0.05). However, TSn, UL', TUL' and TPos did not significantly change (P > 0.05). The soft and hard tissue variation ratios of Sn/A, UL’/UI, LL’/LI, Bs/B, Pos/Po, Gns/Gn were 0.69, 0.59,0.73, 0.85, 0.90 and 0.97, respectively. Conclusion: Profile improvement was remarkable after orthodontic-orthognathic treatment in skeletal class III malocclusion patients. Pearson’s correlation analysis showed that the position predictability was more favorable for the chin compared to the lip. Additionally, the position predictability of the mandible outdid the maxilla.

Key words: skeletal Class III malocclusion, changes in soft and hard tissues, combined orthodontic and orthognathic treatment, pearson linear correlation analysis