下颌第三磨牙阻生类型同体两侧对称性研究

目的研究下颌第三磨牙阻生类型同体左、右对称性。方法收集186例下颌第三磨牙拔除病例数据。所有患者进行临床检查并拍摄曲面断层片。按照Pell—Gregory升支分类、Pell—Gregory牙争平面分类和Winter分类对左、右两侧下颌第三磨牙阻生类型分别进行分类。对两侧下颌第三磨牙阻生类型进行描述性统计分析和Speaman相关分析。结果三种阻生类型两侧完全对称者95例,占51．1％;任意两种阻生类型两侧均对称,另一种不对称者占19．9％;三种阻生类型中仅一种两侧对称,另两种不对称者占14．5％;三种阻生类型两侧均不对称者占14．5％。两侧下颌第三磨牙Pell—Gregory升支分类（r=0．51,P=0．01）、Pell—Gregory铪平面分类（r=0．41,P=0．01）和Winter分类（r=0．48,P=0．01）均有显著相关性,将每侧下颌第三磨牙三种阻生类型合并,两侧也具有显著相关性r=0．67,P=0．01）。结论同体两侧下颌第三磨牙阻生类型具有对称性,一侧下颌第三磨牙的阻生类型、临床病理以及治疗方案对另一侧具有指导意义。

Analysis of the symmetry of impaction types of mandibular third molars bilaterally

Objective To study the symmetry of impaction types of mandibular third molars bilaterally. Methods There were 186 patients included in the study. Clinical and radiographic examinations were performed. The impaction types were classified according to the Pell-Gregory classification （ramus and occusal） and the Winter classification.Descriptive statistics and Spearman bivariate correlate analysis were used. Results Completely symmetry about three impaction types between the right mandibular third molars and the left mandibular third molars were found in 95 patients （51.1% ）. Any two kinds of three impaction types were symmetry but the third was asymmetric were found in 19.9% patients.Only one of the three impaction types was symmetry but the other two impaction types were asymmetry were found in 14.5% patients.Any of three impaction types was asymmetry were found in 14.5% patients. There was significant correlation of any one of three impaction types between the right and the left mandibular third molars. There was significant correlation between the combination of three impaction types bilaterally. Conclusion The symmetry of impaction types of mandibular third molars was found bilaterally.The impaction types,clinical pathology and the treatment of one side of mandimular third molar can be used to predict the other side.