Cone-beam computed tomography analysis of root canal morphology in mandibular first molars in a Chinese population: a clinical study

Background: The aim of this study was to evaluate the root canal morphology of mandibular first molars in a Chinese population by using cone-beam computed tomography (CBCT). Methods: In this study, CBCT images of 900 mandibular first molars were evaluated for the following details: (1) number of roots, (2) number of apical foramina, (3) frequency distribution of root canal configurations defined in accordance with Vertucci’s classification, and (4) frequency of occurrence of middle mesial (MM) canal. Results: Overall, 74.9% of the evaluated mandibular first molars possessed two roots, and 55.4% exhibited three apical foramina. The evaluated teeth exhibited a relatively high prevalence of type IV canals in mesial (M) roots (76.8%) and type I canals in the distal (D) (79.4%), distobuccal (DB) (98.7%), and distolingual (DL) (100%) roots. There were no significant differences in the number of roots, incidence of apical foramina, or distribution of different canal configurations of mandibular first molars between men and women (P > 0.05). 1.9% of mandibular first molars possessed three mesial canals, and the highest frequency of occurrence of MM canals (4.1%) was among Chinese people below the age of 30 years. Conclusions: CBCT scanning facilitates identification of the root canal system. In order to increase the success rate of treatment, it is important to obtain information about the variable morphology of root canals before endodontic treatment. Trial registration: TJSKE20160412. Registered 12 April 2016.