上颌第一、二恒磨牙卡氏牙齿特征的离体牙观察

Observation of Carabelli's traits on permanent maxillary first and second molars in vitro

目的:揭示卡氏尖在上颌恒磨牙的出现特点和规律。方法:采集临床拔除的上颌第一恒磨牙107个,第二恒磨牙125个。病人全部为汉族人,拔牙时记录病人性别、年龄、牙位。10倍放大镜下观察牙体解剖形态。卡氏牙齿特征的表达强度按亚利桑那州立大学牙齿人类学标准系统(The Arizona State University Dental Anthropology System,ASUDAS)分为8个等级进行记分。卡方检验不同性别、不同牙位组卡氏牙齿特征表达率的差异。结果:卡氏牙齿特征在上颌第一、二恒磨牙的出现率分别为52.34%及4.0%(ASU1～7),左右侧、性别差异无统计学意义(P>0.05)。卡氏尖表达强度等级越高,其出现率越低。若卡氏特征二分法阳性标准取ASU3～7,则在第一磨牙的发生率降为18.69%;而牙尖型(ASU5～7)出现率仅为7.48%。结论:采用ASU系统对汉族人卡氏牙齿特征的表达强度进行评估具有重要的人类学价值。

AIM： To investigate the expression of the Carabelli＇s traits on permanent maxillary first and second molars in a Chinese population. METHODS： The expression of Carabellig trait was categorized into 8 grades by the Ari- zona State University Dental Anthropology System （ASUDAS） . A total of 107 extracted permanent maxillary first molars and 125 second molars were collected from a Han Chinese population. The frequencies of occurrence and grades of expression of Carabelli＇s traits were determined under a 10 × magnifying glass. The traits frequencies in different genders and in different sides （right and left） were compared with Chi-square test. RESULTS： The frequency of Carabelli’s trait on permanent maxillary first molars was 52.34% , and 4.0 % of second molars （ ASU 1 - 7 ） ; the gender and side differ- ences had no statistical significance. The percentage decreased quickly as the degree of the expression raised. The trait frequency was 18.69% as the grade 3 -7 （ASU system） was scored as present of the trait; the cusp form （ASU 5 -7） only accounted for 7.48% of total first molars. CONCLUSION： Evaluating the prevalence of the Carabelli’s traits in Chinese populations by using a standardized method （ASUDAS） has great anthropological significance.