Abstract: Objective: To compare the mesial buccal root of the first maxillary molars of Tibetan and Han adults, and provide a reference for clinical root canal treatment. Methods: The 440 CBCT images of the mesial buccal root of the first maxillary molars of Tibetans and Hans were collected randomly. Root length, curvature, bending position, the possibility of second buccal root (MB2), and MB-MB2 distance were measured. Results: The mesial buccal root length of Tibetan was longer than that of Hans (P<0.05). There was a statistical difference in the bending degree of the root canal in the mesial buccal roots between Tibetan and Han people. The majority of the Han people were grade 2 (10°<the bending degree of the root canal <30°), while the Tibetans were grade 2 and grade 3 (the bending degree of the root canal >30°). There was a statistically significant difference between the Tibetan and Han nationalities on the mesial buccal root canal bending position (P<0.05). There was no statistically significant difference in the incidence of MB2 and distance of MB-MB2 between Tibetan and Han people. Conclusion: The root length of the buccal root, the curvature of the root canal, and the position of the root canal are different. The Tibetan tooth root is longer and the curvature is greater, especially at the apical area. There was no difference between MB2 incidence and MB-MB2 distance between Tibetans and Hans.

Key words: CBCT, maxillary first permanent molar, root length, MB2, root curvature