LAUSR

OBJECTIVES The aim of this study was to analyze the incidence, symmetry, concurrence of second mesiobuccal canal (MB2) and determine geometric relationships between each orifice of maxillary first and second molars by cone-beam computed tomography (CBCT) analysis. METHODS A total of 216 qualified individuals' (503 teeth) CBCT image were enrolled in the present study. The consistency of bilateral symmetry and concurrent appearance of MB2 canals were analyzed among individuals with contralateral and adjacent molar teeth. The inter-orifice distances and angulations of first and second molars were also measured. RESULTS The overall incidence of MB2 canal of maxillary molars was 39.2%, in which 45.9% and 32.3% in the first and second molars, respectively. The distribution of MB2 canal in contralateral molar teeth has significant gender difference in second molars (p = 0.024) while analyzing the frequency of MB2 canal appearing in contralateral molar pairs. The simultaneous occurrence of MB2 canal was 22.4% for contralateral molars, and the prevalence of concurrent appearance of MB2 canal in the adjacent molars was 43.4%. After adjusting for gender, age, and tooth type, the inter-orifice distances of mesiobuccal to palatal (odds ratios = 1.891) and to distobuccal (odds ratios = 1.448) canals, demonstrated significant differences between molars with and without MB2 canals. CONCLUSIONS The clinical significance of the results presents critical information on the geometric features, including inter-orifice distances and angulations between each orifice in maxillary molar teeth. Further studies should be conducted to investigate the exact anatomic coordination between each orifice and its impact on access preparation and external crown morphology.