C-Shaped Canal Configurations in Mandibular and Maxillary Second Molars: A CBCT Analysis in a Malaysian Population

C-shaped canals are a complex root canal variation, most frequently observed in mandibular second molars. Their atypical anatomy can make root canal treatment more difficult and may lead to complications if not properly identified. The use of Cone Beam Computed Tomography (CBCT) offers superior visualisation of canals morphology compared to conventional radiography. While the prevalence of C-shaped canals has been reported in various populations, there is limited data regarding their prevalence and configuration in the Malaysian's multiracial population. Understanding these morphological variations is essential for treatment planning and improving clinical outcomes.

This cone beam computed tomography (CBCT) study aimed to determine the prevalence and configuration of C-shaped canals in permanent mandibular and maxillary second molars among the Malaysian population using the Modified Melton's classification.

A total of 274 CBCT images involving 605 second maxillary (n = 269) and second mandibular molars (n = 336) were obtained from Oral Radiology Unit, Faculty of Dentistry, Universiti Sains Islam Malaysia. For each tooth, the canal configurations were evaluated at three different levels: 'coronal', 'middle', and 'apical'. The canal configurations were subsequently classified according to the Modified Melton's classification. The prevalence and canal configuration correlation between sex, ethnicities, and tooth positioning were determined using odds ratio (P = 0.05).

The patients' ages ranged from 12 to 72 years old, with a mean age of 29.47 ± 11.53 years. The patients were female (76.6%) with Malays or Bumiputera (78.8%) predominance. The prevalence of C-shaped canals found was 10.1% (n = 44), and all were presented in second mandibular teeth. The most frequent C-shaped canals configuration found was C3-C3-C3 (29.5%). C-shaped canals were presented more likely when the patient is Chinese than other ethnicities with an odds ratio of 3.18 (95% CI, 1.562-6.488; P = 0.001) and in fused roots than multirooted roots (OR = 173.43; 95% CI, 65.077-462.195; P < 0.001). Sex was not associated with the prevalence of C-shaped canals in this study.

The prevalence of C-shaped canals of the mandibular second molar in the Malaysian subpopulation in this study was 10.1% with the most frequent configuration of C3-C3-C3 at 29.5%. The Chinese ethnicities and tooth with fused roots were more frequently associated with the incidence of C-shaped canals. Identification of the C-shaped canal morphology allows the clinician to modify the canal preparation and obturation techniques to obtain a good endodontic treatment outcome, while also preventing any iatrogenic or procedural errors.