安氏Ⅰ类拥挤拔牙矫治后磨牙及切牙位置变化的研究

目的 :探讨安氏I类错牙合牙列拥挤经拔除 4个第一前磨牙矫治后磨牙及切牙位置的变化。方法 :选用泸州医学院附属口腔医学院正畸科连续收治的安氏I类错牙合牙列拥挤患者 2 0例 (男 8,女 12 ) ,年龄 14～16岁。均采用拔除 4个第一前磨牙 ,用方丝弓细丝弓技术矫治 ,牙性支抗。在矫治前后摄X线头颅定位侧位片 ,对磨牙及切牙位置进行测量比较分析。结果 :上颌磨牙牙冠平均前移 3 .15mm ,上颌切牙牙冠平均后移 2 .5 5mm ;下颌磨牙牙冠平均前移 4.3mm ,下颌切牙牙冠平均后移 1.78mm。结论 :牙性支抗 (弱支抗 )控制下 ,安氏Ⅰ类错牙合牙列拥挤拔牙矫治后上下磨牙及切牙位置均有明显变化 ,且相对RL线磨牙前移较切牙后移更大。

Position change of upper incisors and molars after extraction of first premolars in cases with Angle class I malocclusion and crowding

Objective: To observe the position change of the upper mol ar s and incisors in cases with Angle class I malocclusion and crowding treated by extraction of four first premolars. Methods: 20 patients with An gle class I malocclusion and crowding aged 14-16 years old, 8 male and 12 femal e, were treated by extraction of the four first premolars, and Edgewise applianc e. Two X-ray cephalometry films were taken for every patient before and after t reatment, cephalometry measurements were obtained and the position of the upper molars and incisors were analyzed. Results:The treatment was co mpleted in 18 month on average in all patients. After treatment, the crown of th e upper first molars showed mesial displacement of 3.15 mm on average, the crown of the upper incisors distal displacement of 2.55 mm, the crown of the lowe r first molars mesial displacement of 4.3 mm, the crown of the lower incisors d istal displacement of 1.77 mm. Conclusion: With of dental anchor age, the position changes of the upper molars and incisors in the cases with Ang le class I malocclusion and crowding after extraction treatment may be achived.I n relation to RL line,the mesial displacement of molars are larger than the dist ally displacement of incisors.