【摘要】 目的 确定上颌第三磨牙萌出与第一磨牙和第二磨牙轴倾度的关系。方法 研究样本分为两组，第一组的研究对象(n=30)具有完整的正常牙列，包括上颌第三磨牙。第二组的研究对象(n=30)存在上颌左右两侧第三磨牙阻生。在曲面断层片上分别测量上颌第一和第二磨牙与腭平面所成的角度。用U检验对两组测量角度的平均值进行比较，Spearman 相关系数估计年龄因素的影响，用Logistic回归分析第三磨牙的萌出与第一磨牙、第二磨牙的轴倾度、性别和年龄之间的关系。结果 上颌第三磨牙萌出组与未萌出组相比，上颌第一磨牙和第二磨牙更向近中倾斜，而且随年龄的增加倾斜度也变大。Logistic回归结果显示第一磨牙的轴倾度是第三磨牙萌出的一个预测因子。结论 第三磨牙萌出与上颌第一、第二磨牙较大的近中倾斜有关。

    【关键词】 第三磨牙；阻生；轴倾度

    The relationship between the sagittal inclination of the first and second maxillary molars and the eruption of the third molars

    LIU Li，LIU Dong-xu，WANG Chun-ling，et al.Department of Orthodontics, School of Stomatology, Shandong University, Jinan 250012, China

    【Abstract】 Objective To determine the relationship between the sagittal inclination of the first and second maxillary molars and the eruption of the third molars. Methods The sample consisted of 2 groups. The subjects in the first group (n = 30) had complete normal dentitions including third molars; those in the second group (n =30) had impacted right and left third molars. The sagittal inclinations to the palatal plane of the first and second maxillary molars were measured on panoramic tomography. The U test was used to compare mean angular values between the 2 groups. Spearman correlation coefficients were calculated to assess the relationship with age. Results Maxillary first and second molars were more mesially inclined in the first group, particularly in the younger subjects (16～25 years). This inclination increased with age. The logistic regression showed that the sagittal inclination of the first molar is a predictor of the eruption of the third molar. Conclution More mesially inclined maxillary molars are likely to be associated with third molar eruption. ......