C-shaped canals—prevalence and root canal configuration by cone beam computed tomography evaluation in first and second mandibular molars—a cross-sectional study

Objectives: C-shaped root canal configuration is an unusual root canal morphology and one of the most often anatomical variations in root canal systems of second mandibular molars. The purpose of this study was to assess the prevalence, symmetry and configuration of C-shaped canals in first and second mandibular molars in an Israeli population using cone beam computed tomography (CBCT). Materials and methods: One thousand twenty Israel patients’ CBCT scans were screened and evaluated. First and second mandibular molars with C-shaped canals were identified. Prevalence configuration along the root and symmetry were analyzed, and new radicular groove classification was proposed. Results: Total of 1465 mandibular second molars and 1229 mandibular first molars were evaluated. The overall prevalence of C-shaped canals in first and second mandibular molars was 0.16 and 4.6%, respectively. No significant difference was found by gender or side of occurrence. The unilateral prevalence of C-shaped canals in mandibular second molars was 55%. C-shaped canal configuration changed along the root in 63% of the cases. Conclusions: The prevalence of C-shaped canals in first and second mandibular molars in the Israeli population is low in comparison to other subpopulations. Clinicians should be aware of the possible asymmetry, different configuration along the root, and the location of danger zone of this anatomic variation during clinical work. Clinical relevance: CBCT is an efficient three dimensional radiographic examination for evaluation of C-shape root canal configuration. CBCT may help the clinicians during clinical work for considering appropriate cleaning, shaping, and obturation technique according to the characteristic of C-shape root canal configuration.