Purpose: The purpose of this study was to analyze the changes of soft tissues at each treatment stage in patients with skeletal Angle Class III malocclusion after orthodontic-orthognathic surgery and to assess the long-term stability after treatments.
Methods: 24 patients with skeletal Angle Class III malocclusion were included in this study. Standardized lateral cephalograms at the following stages were taken for each patient:T(0)-before treatment; T(1)-3 months after surgery; T(2)-1 year after surgery; T(3)-3 years after surgery. A total of 13 soft tissue landmarks were selected and the angles at different stages were evaluated. SPSS12.0 software package was used to calculate x and s,q test was used to evaluate the changes of the soft tissues.
Results: (1)Comparison between stage T(0) and T(1):x all landmarks had significant difference except the angle of A'UL-B'LL. (2)Comparison of the angles between stage T(1) and T(2) : the angles of S-N'-B, G-Sn-Pos, Ns-Sn-Pos, FH-SnPos and Z had significant difference. (3)Comparison of the angles between stage T(1) and T(3) :the angles of S-N'-B',G-Sn-Pos,Ns-Sn-Pos,FH-SnPos,Z and Ns-Prn-Pos had significant differences. (4)Comparison of the angles' changes between stage of T(2) and T(3): only G-Sn-Pos had significant diversity.
Conclusions: Angles related with Pos are more likely to relapse, but on the whole, the treatment effect is stable.