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目的:通过全颌曲面断层片分析10岁儿童第三磨牙的生长发育情况,为临床和基础研究提供参考。方法:从华西口腔医院影像资料库中随机抽取2009年6月～2010年7月期间拍摄的10岁儿童全颌曲面断层片共426张,研究分析第三磨牙的生长发育情况。结果:32.57%的第三磨牙牙位处不能观察到牙胚或钙化影像,女性较男性的发育较早,下颌第三磨牙发育较上颌第三磨牙相对早,左侧和右侧第三磨牙发育无明显差别。第三磨牙近远中径为(11.42±0.86)mm,牙齿长度为(8.44±1.30)mm,第三磨牙与下颌第二磨牙牙体长轴所成夹角为30.79±13.82°。结论:大部分10岁儿童的第三磨牙处于牙冠钙化阶段,同龄女性第三磨牙较男性的发育较早,下颌较上颌发育较早,左右侧发育无明显差别。第三磨牙的近远中径与牙齿长度,男女、左右间均无明显差异。第三磨牙与第二磨牙牙体长轴所成夹角,右侧大于左侧,两侧间有明显差异。
OBJECTIVE: To analyze the growth and development of the third molars in 10-year-old children by means of whole-jaw curved tomography and to provide a reference for clinical and basic research. Methods: A total of 426 mandibular craniofacial slices were collected from the Huaxi Stomatological Hospital Image Library from June 2009 to July 2010. The growth and development of the third molars were analyzed. Results: No tooth germ or calcification was observed in 32.57% of the third molars. The development of the third molars in mandibular third molar was earlier than that in the third molars, and the third molars in the left and right were developed No significant difference. The mesial diameter of the third molars was (11.42 ± 0.86) mm and the length of the teeth was (8.44 ± 1.30) mm. The included angle between the third molars and the mandibular second molar teeth was 30.79 ± 13.82 °. Conclusions: The third molars of most 10-year-old children are in the stage of crown calcification. The third molars of same age women developed earlier than the male ones. The mandibular jaw developed earlier than the maxilla and there was no significant difference between the left and right sides. There was no significant difference between the mesial diameter of the third molars and the length of the teeth, between men and women. The angle formed by the third molars and the second molar tooth axis is greater than the left, with significant difference between the two sides.