安氏Ⅱ类1分类成年与青少年拔牙治疗的软组织改变

Profile changes in class Ⅱ, division 1 malocclusion: A comparison of the effects of tooth extraction in the adults and the juveniles

目的：探讨安氏Ⅱ类１分类成年与青少年拔牙治疗后其软组织改变的差异。方法：选择经拔除４个第一前磨牙进行正畸治疗结束的安氏Ⅱ类１分类错牙合患者３２例（其中成人与青少年各１６例），应用Ｘ线头影测量技术对其治疗前后软组织发生的变化进行测量研究，并对两年龄组的测量结果加以分析比较。结果：（１）经拔牙治疗青少年患者侧面凸度明显变小，而成年人没有明显改变。（２）青少年患者治疗后由于上唇突软组织增厚，软组织颏前点前移，使正畸治疗后的侧貌轮廓较成人更为满意，而成人由于正畸治疗其上唇及下颌顺时针旋转的改变易致“正畸面容”。结论：临床上预测拔牙治疗后上唇位置，不但要考虑上唇与上切牙后退比例，还应结合上唇软组织厚度的生长发育改变的结果。

Objective: To compare the profile changes in adults and juveniles with Class Ⅱ division 1 malocclusion after extraction of the four first premolars.Methods:32 patients(16 adults and 16 juveniles) with Class Ⅱ division Ⅰ malocclusion after extraction of the 4 first premolars were investigated with cephalometric analysis. The facial morphology and soft tissue profile before and after teeth extraction were compared. The date were analysed with Student's t tests.Results:(1) 2.9 degree decrease in soft tissue profile convexity was observed in juvenile group, however no change was found in adults group( P <0.05). (2) More than 2.4 mm thickness increase of superior lip and 3.1 mm forward displacement of soft chin were observed in the juvenile group than in the adult( P <0.01). Conclusion:The growth of upper lip and the ratio of upper lip retraction to upper incisor retraction should be considered for the predication of the lip position in the orthodontic treatment when the first premolars are being extracted.