A study on skeletal relapse patterns following orthognathic surgery of Class III patients : comparison between SSRO and IVRO

Lee, Jang Yeol; Yu, Hyung Seog; Ryu, Young Kyu

Abstract

To evaluate the relapse pattern and long-term stabilities depanding on surgical methods following orthognathic surgery of Cl III patients, the author selected 24 subjects(10 male, 14 female) operated by SSRO and 26 subjects(10 male, 16 female) operated by IVRO. Each subject took four lateral cephalograms: just before surgery(Tl), within 48hrs after surgery(T2), 4-8 wks after surgery(T3), 6 month or more after surgery(T4), and the landmarks were digitized. The differences of relapse patterns in each interval between two groups were compared and the significance of correlation among the variables of each group was tested The obtained results are as follows; 1. Horizontal early relapse was forward movement of mandible in SSRO group, as compared to the backward movement in IVRO group, and there was a statistical significance between the two groups. 2. Vertical early and late relapses were decreases in anterior facial height in both groups and there was no statistical significance between the two groups. 3. There was a statistical significance in negative correlation between mandibular hornontal late relapse and surgical change of articular angle in SSRO group. 4, There was a statistical significance in negative correlation between amount of mandibular set-back and mandibular horizontal early relapse in both groups.