Imaging study on the root and root canal morphology distribution of maxillary first molars

MALIYAMUGULI·Pataer; AERMAN·Abulizi; YU Tiantian; ZHAO Jin

doi:10.15956/j.cnki.chin.j.conserv.dent.2026.02.005

Abstract：Objective To investigate the distribution of root and canal morphology in maxillary first molars using cone-beam computed tomography(CBCT).Methods CBCT images of patients who required examination for treatment purposes at the Affiliated Stomatology Hospital of Xinjiang Medical University between January 2024 and August 2025 were retrospectively reviewed.Patients meeting the inclusion criteria were selected.The number of roots,the incidence of the second mesiobuccal canal(MB2),and the morphology of the mesiobuccal root canals were analyzed and compared bilaterally.Results A total of 1 507 patients were included,comprising 963 females(63.90%)and 544 males(36.10%).The maxillary first molars were predominantly three-rooted(99.73%)and four-canaled(52.68%).Two-rooted teeth(0.27%),five-canaled teeth(0.40%),and two-canaled teeth(0.27%)were rare.Single-rooted,four-or-more-rooted,single-canaled,or six-or-more-canaled teeth were not observed.The prevalence of three roots was significantly higher than that of two roots(χ2=2 982.085,P<0.001).The overall incidence of MB2 was 52.95%,with no statistically significant differences between left and right sides(χ2=0.261,P=0.609)or between genders(χ2=3.572,P=0.059).Regarding the morphology of the mesiobuccal root canals,TypeⅠ(single canal)accounted for 47.05%.Among the multi-canal configurations,Type Ⅱ was the most common(33.19%),followed by TypeⅣ(18.85%).Types Ⅲ,Ⅴ and Ⅷ were the least prevalent,at 0.53%,0.27%,and 0.13%,respectively.The overall incidence of multi-canals in the mesiobuccal root(52.95%)was higher than that of single canals(47.05%),with no significant difference in the incidence of single versus multi-canals between left and right sides(χ2=0.261,P=0.609).Conclusion Maxillary first molars exhibit complex root canal morphology,frequently presenting with multiple root canal configurations and bilateral symmetry.