Abstract:

Abstract：Objective To investigate incidence of MB2 in the maxillary first molar，mesiobucaal root canal morphology and locations of mesiobucaal root canal orifices by using cone beam computed tomography. Methods Choose 160 CBCT images（male 80，female 80）randomly from the image database aged from 20 years old to 30 years old. Observe mesiobuccal root canal system and categorize them by Vertucci’s classification. Locate root canal orifices from a horizontal angle and record the distance between root canal orifices of MB，MB2 and Palatine and the angle between MB-P and MB2-P.Compare the statistical differences between male and female. Results There were 233 teeth having MB2 out of 279 teeth and the incidence of MB2 was 83.5%. Different types of canals had different incidence. Evidence showed there were no differences between male and female. The distance between MB and MB2，however，was different between male and female. Conclusion The incidence of MB2 in the maxillary first molar is high. There are no statistical differences of different types of canal system between genders. Male and female have different distance of MB-MB2.

Key words: root canal images, cone beam computed tomography（CBCT）, maxillary first molar mesiobuccal root

摘要：

目的 利用锥形束计算机断层扫描（CBCT）研究上颌第一磨牙近中颊根第二根管（MB2）发生率、根管解剖形态以及根管口位置分布。方法 随机选取2011—2013年航天中心医院口腔科20～30岁患者CBCT影像160张（男80张、女80张）。平行近中颊根长轴平面观察其根管形态，并按照Vertucci分类统计。水平面观察根管口的位置，记录MB、MB2及腭根根管口间距离以及MB、MB2根管口分别到腭根根管口连线夹角，并比较不同性别间差异。结果 本研究观察了279颗上颌第一磨牙，其中存在MB2牙齿233颗，检出率为83.5%，不同性别间差异无统计学意义（P＞0.05）。不同类型的根管出现概率不同，各类型出现率男女间无差异。MB与MB2根管口间距男性为（2.195 ± 0.504）mm，女性为（1.966 ± 0.419）mm，差异有统计学意义（P < 0.05）。结论 上颌第一磨牙MB2发生率高，不同类型MB2发生概率不同，男性与女性之间无差异。MB与MB2根管口间距在两性之间存在统计学差异。

关键词: 根管影像, 锥形束计算机断层扫描, 上颌第一磨牙近中颊根