猪第一恒磨牙根尖定位的解剖学研究

An anatomical study of the location of the root apex in mandibular first permanent molars in pigs

目的为更好地利用猪颌来训练口腔医学生掌握根尖外科手术的方法,研究猪第一恒磨牙根尖定位的解剖学特点,为实验教学提供依据。方法选取第一恒磨牙都已完全萌出、恒牙列完整的48个猪一侧下颌作为实验对象,用游标卡尺测量猪第一恒磨牙全长(根尖在术区骨面的投影位置至牙尖的距离)、根尖至术区侧的距离、近远中径、颊舌径和临床牙冠长度,用SPSS软件对数据进行各种统计分析。结果猪第一恒磨牙全长平均值为27.98mm。根尖至术区侧的距离平均值为4.53mm。对同一颗牙的近远中径、颊舌径和全长进行直线回归分析,其回归方程差异均有统计学意义。对同一颗牙的临床牙冠长度与全长进行直线回归分析,对同一颗牙的近远中径和颊舌径与根尖至术区侧的垂直距离进行直线回归分析,其方程差异均不具有统计学意义。结论在利用猪颌作为模型进行根尖外科手术实验中,可根据牙的近远中径和颊舌径,参考本研究计算出的猪第一恒磨牙全长的平均值,粗略估计根尖在术区骨面投影龈向的位置。

Objective For better use of pigs＇ mandibles as models in endodontic surgery,the study assesses the location of the root apex in mandibular first permanent molars in pigs.Methods 48 pigs＇ mandibles were selec-ted.All had sound permanent teeth and the first molars had erupted.The tooth length（distance between dental cusp and root apex location shadowed through bone）,the distance between root apex location and the buccul surface of the bone,mesiodistal width,buccolingual width,and the length of the clinical crown were measured with a vernier calliper.SPSS software was used to analyze the data.Results The average tooth length was 27.98 mm,and the average distance between the root apex and buccal surface of the bone was 4.53 mm.Linear regression analysis showed significant relationship between the buccolingual width and tooth length,mesiodistal width and tooth length.No statistically significant relationship were found in other indices.Conclusion The experiment found that the buccolingual width,mesiodistal width and the average tooth length can be used for predicting the location of the root apex.