骨性安氏Ⅱ类错牙合颅颌结构改变的Downs分析研究

A study on change in craniomandibular structure of skeletal Angle class Ⅱ malocclusion with cephalometric Downs analysis

目的：研究恒牙列初期骨性安氏Ⅱ类错牙合的颅颌结构变化，确立该类错牙合的矫治时机．方法：随机抽取临床４０例恒牙列初期的安氏Ⅱ类１分类错牙合患者，进行近１年时间的观察．对观察前、后患者的侧位定位ｘ线头影片做Ｄｏｗｎｓ法测量分析及配对ｔ检验．结果：处于恒牙列初期的女性患者，上下颌骨关系已无明显变化，但上颌切牙表现的更加前突，下颌切牙更加舌倾；男性患者的下颌骨表现为向前、向上方向旋转生长，其变化数值有统计学意义．结论：对骨性安氏Ⅱ类错牙合患者需及早施以矫治．

Objective: To investigate craniomandibular structure change of skeletal Angle class Ⅱ malocclusion in early permanent dentition for deciding treatment opportunity of the deformity. Methods: Forty skeletal Angle class Ⅱ division 1 patients in early permanent dentition were selected at random and observed for one year. The lateral cephalometric X ray films were taken before and after observation for every patient, then Downs analysis and pairing t test were made. Results: Female patients' jaws relation didn't change in early permanent dentition, but upper incisors were more protrusive than before, and lower incisors were inclined to lingual side. Male patients' mandible grew upward and forward. The difference reached statistical significance. Conclusion: Early correction for skeletal Angle class Ⅱ malocclusion is essential.