第三磨牙发育以及形态的研究

目的 探讨第三磨牙牙冠与牙根的形态特征,为第三磨牙的拔除与保留提供理论依据.方法 利用曲面断层片对第三磨牙的牙冠宽度、牙冠高度、牙根长度、牙颈宽度、牙根尖宽度5个指标进行测量,并对男女不同性别第三磨牙形态大小进行t检验,比较磨牙形态差异.结果 在5个测量指标中,男性测量值均大于女性,经统计分析男女下颌第三磨牙形态测量差异无统计学意义,上颌第三磨牙的牙根长度与牙根尖宽度的差异存在统计学意义.结论 男性第三磨牙较女性粗大;男女下颌第三磨牙形态大小差异较上颌第三磨牙小.

A study of morphological characteristics and development of the third molar by X-ray

Objective To discuss the morphological characteristics of the molar crown and the root of the third molar（M3）,and to offer the theoretical basis for whether extracting or keeping the third molar. Method We use the panoramic film to measure the crown width, crown height, root length, tooth neck width and the distance of apex of the third molar,and make t test among them to find out the differences between differet genders. Result There are no differences between female and male in the five measure values to the third molar in mandibular, the differences of the third molar in maxillary between female and male exist in the root length and the distance of apex. Conclusion The root of the third molar in male is stronger than in female, and the differences of the third molar in mandibular between female and male are more outstanding than in maxillary.