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目的研究不同正畸治疗方法对阻生下颌第三磨牙的影响。方法选择2005年1月至2008年5月青岛大学医学院附属医院口腔正畸科治疗的第三磨牙阻生青少年患者79例(154颗患牙),按治疗前下颌第三磨牙倾斜角及矫治是否拔牙分为4组:未拔牙A组(非拔牙矫治且倾斜角≤30°),未拔牙B组(非拔牙矫治且倾斜角>30°),拔牙A组(拔牙矫治且倾斜角≤30°),拔牙B组(拔牙矫治且倾斜角>30°)。拍摄正畸治疗前后口腔曲面断层片,测量并计算矫治前后下颌第三磨牙倾斜角及萌出间隙的变化。结果矫治后拔牙A组第三磨牙倾斜角比矫治前平均减小3.36°,且差异有统计学意义(P<0.05);其余各组矫治前后差异均无统计学意义。矫治后各组下颌第三磨牙的萌出间隙均高于矫治前,且差异有统计学意义(P<0.05),其中拔牙组矫治前后萌出间隙变化尤为明显。结论对于原倾斜角较小的下颌第三磨牙,拔牙有利于改善第三磨牙的萌出角度;与非拔牙矫治相比,拔牙矫治更多地增加了下颌第三磨牙的萌出间隙,有利于下颌第三磨牙的萌出。
Objective To study the effect of different methods of orthodontic treatment on impacted mandibular third molars. Methods From January 2005 to May 2008, 79 cases (154 teeth) of adolescent patients with third molars treated by orthodontics in Affiliated Hospital of Medical College of Qingdao University were enrolled in this study. According to the inclination and treatment of premolar third molars Tooth extraction was divided into 4 groups: untreated group A (non-extracorrecting and incline ≤30 °), untreated group B (non-extracorrectation and incline angle> 30 °), extraction group A °), tooth extraction group B (extraction treatment and tilt angle> 30 °). Before and after orthodontic treatment, the malformation of the oral cavity surface was measured and the tilt angle and eruption gap of mandibular third molar before and after orthodontic treatment were measured and calculated. Results After treatment, the tilt angle of the third molar in group A was 3.36 ° lower than that before treatment, and the difference was statistically significant (P <0.05). There was no significant difference between the other groups before and after treatment. The eruption clearance of mandibular third molars in each group after correction was higher than that before treatment, and the difference was statistically significant (P <0.05). The change of eruption gap before and after tooth extraction group was more obvious. Conclusion Extraction of teeth is beneficial to improve the eruption angle of the third molars for mandibular third molars with less primary tilt angle. Compared with non-extraction treatment, tooth extraction can increase the eruption space of mandibular third molar more, Three molar eruption.