Abstract: Objective To investigate the effect of extraction therapy on the vertical structure of craniomaxillofacial region in patients with high angle.Methods A retrospective analysis was conducted for 76 cases of high angle cases in orthodontics from February 2014 to August 2015 who were divided into two groups according to treatment regimens.The observation group (n=40) was treated with orthodontic premolars,and the control group (n=36) used using non-extraction treatment program.The changes of craniomaxillofacial vertical structure of the two groups by two different treatment regimens were measured using X-rays.Results After treatment,ANS-Me,L6-MP,N-Me and U6-PP in the two groups were significantly higher than those before treatment (P<0.05).There were differences in Y-axis and L6-MP between the two groups (P<0.05).Conclusion There is no significant change in the structure of mandibular plane angle and growth direction before and after orthodontic treatment.The height of molar is higher in the observation group than in the control group.

Key words: Extraction treatment, High angle, Craniomaxillofacial vertical structure