摘要
目的观测成人下颌骨第三磨牙的阻生关系。方法根据吴氏《人类骨骼测量方法》中规定的年龄估计及性别鉴定的标准 ,观测成人下颌骨的形态结构。结果 3 0 2个下颌骨标本的观察结果为 ,男女混合阻生率为 1 0 .60 % ,女性阻生率高于男性 ,肉眼见无第三磨牙萌出者 1 0 6例 ,经X线拍片验证 ,5例有埋没牙存在 ,故实际第三磨牙缺如率为 3 3 .4 4%。从测量数据可见阻生组 (无第三磨牙组 )的第二磨牙后间隙、下颌斜长、下颌体长及髁突间宽均较正常组小。结论无第三磨牙可能是人类进化过程中 ,下颌骨与牙齿均衡退化的结果 。
Objective To detect something relate to genesis of impaction of the third molar in adults.Methods According to the standard defined by Wu(《The observing methods of human′s skeleton》),302 specimens of adults mandible were examined.Results Among the 302 specimens of adults,mandibles,the general (male and female) incidence rate of third molar was 10.60% with some of female prevalence.On macroscopic examination none of the third molar was found in 106 mandibles.But among them upon X ray photpgraphic examination third molar was noted to be embedded in 5 mandibles.Thus,the rate of actual absence of mandibular third molar was 33.44%. The data obtained indicated that the sizes of the space posterior to the second molar,the oblique length of the mandible,the length of the mandibular body and the distance between the two condyloid processes in the impacted(third molar absence) group wese all shorter than that of normal group.Conclusion Lack of space for eruption may be one of the direct causes of the impaction of teeth. The absence of the third molar may be the result of the balanced degeneration of mandibe and tooth in human evolution,and the impacted third molar may be the transitional stage from the presence to the absence of the third molar during the evolution.
出处
《咸宁医学院学报》
2001年第3期153-156,共4页
Journal of Xianning Medical College
