CBCT Imaging Analysis of Relative Position between First and Second Mandibular Molars and Mandibular Canal

doi:10.13701/j.cnki.kqyxyj.2024.09.010

Abstract

Abstract: Objective: To analyze the root distribution of the first and second mandibular molars, as well as the relative orientation and distance between the root tip and the mandibular canal. Methods: The cone beam computed tomography (CBCT) images of patients who visited the Department of Stomatology at Zhongnan Hospital of Wuhan University in the past 2 years were selected. After screening with inclusion criteria, the proportion of root types of the first and second molars in CBCT was analyzed, as well as the relative orientation and distance between the root tips and the mandibular canal. The differences in the relative positions between different genders and between the left and right sides were compared. Results: (1) In the overall population, the number of mandibular second molars with two root types was higher than that with single root types, with more two root types in males and more single root types in females (P<0.001). The number of mandibular first molars with two root types was more than that with three root types, and there was no significant difference between genders. There was no significant difference in the root distribution of the first and second molars on the left and right sides. (2) The root of the second molar was mainly located directly above the neural canal, followed by the upper part of the lingual side, and was least commonly distributed above the buccal side. The mesial root of the first molar and the distal root of the two root type first molar were mainly distributed above the neural canal, followed by the upper buccal side, and the least commonly distributed above the lingual side. The distal buccal roots of the three types of first molars were mainly distributed above the buccal side, followed by directly above. The distal lingual roots of the three types of first molars were mainly distributed above the lingual side, and rarely located directly above. There was a significant difference (P<0.05) in the relative orientation of the second molars with two roots in the left and right sides. There was a gender difference (P<0.01) in the relative orientation of the two root type first molar. (3) The second mandibular molar was closer to the mandibular canal than the first molar (P<0.001). In these three types of roots, males got further distance than females: the mesial root tips of second molars with two roots (P<0.001), the distal root tips of second molars with two roots (P<0.001), and the distal buccal root tips of first molars with three roots (P<0.05). There was no statistically significant difference in the distance between left and right sides. Conclusion: The second mandibular molar is closer to the nerve canal than the first molar. There are gender differences in the distribution of root types and the distance between the root tip and the nerve canal in some mandibular molars, and there are differences in the orientation of the root tip relative to the nerve canal between males and females, as well as between the left and right sides in some root types.

Key words: mandibular canal, cone beam CT, mandibular molars, root tip

YANG Sisi, CHENG Bo, YIN Miao, WENG Xiuhong, YANG Fuhua. CBCT Imaging Analysis of Relative Position between First and Second Mandibular Molars and Mandibular Canal[J]. Journal of Oral Science Research, 2024, 40(9): 810-815.

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