C-Shaped Canal Prevalence and Morphology in Maxillary Molar Teeth: A Cone Beam Computed Tomography Evaluation

Abstract

Background: The aim was to evaluate the prevalence and morphology of the C-shaped root canal(s) in maxillary molar teeth using cone beam computed tomography (CBCT) images. Methods: In 2024, the maxillary CBCT volumes of 475 patients were evaluated for C-shaped canal morphology at 3 different axial levels of the molar roots. Classification of the C-shaped canal was done according to the root fusion type, followed by consecutive axial slices with an upper-C (UC)1 or UC2 configuration. The Z-test for proportions in independent groups was used to analyze the differences between location (left and right sides) and tooth (first or second upper molars). The chi-square test was used to compare root fusion types (P=.05). Results: C-shaped canal morphology was found in 4.89% of 797 maxillary molars. C-shaped canal was encountered in 8% of maxillary second and 2% of maxillary first molars. Six different types of UC configurations were observed, with type-A canal structure (23%) having the highest occurrence (P > .05). UC1 configuration was more common in the second molars at the middle (P=.017) and apical levels (P=.007). Conclusion: Despite the low prevalence, high complexity in morphology requires the attention of clinicians regarding C-shaped maxillary molars to avoid failures and complications.