Evaluation of Root and Canal Morphology of Maxillary Permanent First Molars in a North American Population by Cone-beam Computed Tomography

Introduction: The purpose of this study was to evaluate the number of roots and canal morphology of maxillary permanent first molars in a North American population. Methods: Three hundred seventeen cases with bilateral maxillary first molars were included. All images from cone-beam computed tomography were carefully reviewed by 2 endodontists. Frequency of number of roots, presence of an additional mesiobuccal canal (MB2), and Vertucci canal type for each root were tabulated. Age, gender, and ethnicity differences were calculated with the X-2 test. The intra-rater reliability was assessed by using the Cohen kappa statistic. Results: The fused root rate was 0.9%. The occurrence of 3-rooted maxillary first molars differed between left and right sides (P =.03). MB2 occurrence only showed statistically significant differences among age groups (P =.005). In the mesiobuccal roots, the most common Vertucci classifications of canal types were type IV (2-2, 41.9%), type I (1, 28.3%), and type II(2-1, 26.3%). There was a statistically significant difference in Vertucci classification of canal type among 5 ethnic groups (African American, Asian, Hispanic, Other, and Non-Hispanic white, P <.001). Conclusions: Cone-beam computed tomography facilitates the identification of root and canal configuration. The information gained about the tooth anatomy and canal morphology before treatment could potentially facilitate root canal therapy.