Abstract: Objective Based on cone beam computed tomography (CBCT), the distribution and related data of bifid mandibular canals were studied, so as to provide guidance and basis for clinical practice. Methods Fourhundred adult people (800 sides of mandible) in Shanxi Province were taken CBCT to measure and analyze the prevalence, length, diameter and angle of bifid mandibular canals, and to explore the influence of gender, left and right sides and different age groups on bifid mandibular canals. Results The incidence of bifid mandibular canal was 40.75% (163/400), which occurred in 248 sides (31.0%). In the classification of bifid mandibular canals, the proportion of retromolar canal, dental canal, forward canal and buccolingual canal was 45.97%, 23.39%, 28.63% and 2.02%, respectively. The average diameter and length of bifid mandibular canals were（1.18±0.36）mm and（12.58±4.72）mm respectively, and the average angle with the main mandibular canal was (42.46±18.14)°. Conclusions The incidence of bifid mandibular canal is high in adults in Shanxi Province, especially in the posterior molar area. CBCT should be taken to estimate the risk before surgery, so as to avoid serious complications caused by intraoperative injury.

Key words: bifid mandibular canal, cone beam CT, incidence, retromolar canal