中文摘要：

目的：通过锥形束CT （cone beam CT,CBCT） 研究下颌前牙的根管构型,为临床根管治疗提供参考依据.方法：选取北京大学口腔医学院自2012年10月至2013年7月进行CBCT检查的866名患者的影像资料,由牙髓专业医生和放射专业医生共同筛取未进行根管治疗和牙根发育完整的下颌前牙4 674颗.根据牙位和年龄分组,观察牙根、根管数目和根管构型,并进行分析.结果：下颌中切牙和侧切牙均为单根,0.7% （11/1 542）的尖牙为双根.中切牙、侧切牙与尖牙的双根管率分别为6.7% （105/1 566）,17.4% （273/1 566）和3.0% （46/1 542）.下颌前牙为双根管的患者中,双根管对称发生的比例为中切牙58.7% （37/63）,侧切牙76.1% （108/142）,尖牙29.6% （8/27）.各年龄组下颌中切牙、侧切牙和尖牙双根管率最高的分别为31~40岁年龄组（9.8%,28/287）,31~40岁年龄组（21.5%,61/284）,51岁（含51岁）以上年龄组（9.2%,19/207）.下颌前牙双根管构型多为Type Ⅲ.结论：下颌侧切牙双根管率、双根管对称发生率最高,下颌前牙双根管构型以Type Ⅲ型为主.

英文摘要：

Objective： To investigate the root canal configuration of mandibular anterior teeth with cone beam computed tomography （CBCT）. Methods： The CBCT imaging data of 866 patients who visited Pe- king University School of Stomatology from October 2012 to July 2013 were inspected by an endodontist anda radiologists together. A total of 4 674 mandibular anterior teeth were involved. The number of root, root canals and root canal configuration were observed and analyzed statistically （Chi-squared test）. Re- sults： All the mandibular central incisors and lateral incisors were single root, and 0.7% （11/1 542） of canines were double roots. 6.7% （105/1 566） of central incisors, 17.4% （273/1 566） of lateral inci- sors and 3.0% （46/1 542） of canines had double root canals. The frequency of symmetry of double root canal was 58.7% （37/63） in central incisors, 76.1% （108/142） in lateral incisors and 29.6% （8/ 27） in canines. The highest frequency of double root canals in different ages was 9.8% （28/287, 31 - 40 years） in central incisors, 21.5% （61/284, 31 -40 years） in lateral incisors and 9.2% （19/207, ≥51 years） in canines. Vertucci type m canal configurations were the most prevalent in mandibular an- terior teeth. Conclusion： The double root canals are most common in mandibular lateral incisors. The highest incidence of symmetry of double root canal is also observed in mandibular lateral incisors. Vertueci type m canal configurations are the most frequent type in mandibular anterior teeth.