Anatomical Investigation of C-shaped Root Canal Systems of Mandibular Molars in a Middle Eastern Population: A CBCT Study.

AIM: The aim of this study is to identify the prevalence of C-shaped root canal systems in mandibular first and second molars in a Lebanese population, and to determine the relationship between C-shaped root canal systems and different factors (age, gender, and tooth location) and to examine the root canal system's morphology along the root. MATERIALS AND METHODS: The presence of C-shaped root canal systems in 648 mandibular molars from 257 patients was analyzed using cone-beam computed tomography (CBCT). The sample included 296 and 352 mandibular first and second molars, respectively. The frequency of C-shaped canals, their relationship to gender, age, and tooth location, and unilateral or bilateral occurrences were noted. A 3D Slicer 4.10.1 was then used to classify teeth with identified C-shaped anatomy according to Fan's configuration and to determine the distance between the orifice and the cementoenamel junction (CEJ). RESULTS: C-shaped root canal systems were detected in 1.01 and 9.09% of mandibular first and second molars, respectively. In mandibular second molars, the most prevalent configurations were as follows: C1 at the orifice level, C3 at orifice-2 mm, C2 and C3 in the middle third, and C3 at the apical level. There was no correlation with age, gender, and tooth position. The bilateral occurrence happened in 60% of cases. Orifices were at a mean distance of 3.32 mm below the CEJ. The deepest groove was mostly lingual. CONCLUSION: The prevalence of C-shaped root canal systems in the Lebanese population is 1.01 and 9.09% in the first and second mandibular molars, respectively. The CBCT slices showed that the configuration varies along the root and that the orifices are at various distances below the CEJ. Therefore, pre-operatory scans can be beneficial for better understanding and preparation of root canal treatment. CLINICAL SIGNIFICANCE: In the Lebanese population, C-shaped mandibular molars are not a rare finding. Clinicians should consider the different configurations and the possible changes along the root.

Anatomical Investigation of Middle Mesial Canals of Mandibular Molars in a Middle Eastern Population: A Cross-sectional Cone-beam Computed Tomography Study.

AIM: To identify the prevalence of middle mesial canals (MMC) in mandibular molars in a Lebanese population to determine the relationship between MMC and different factors (age, sex, and tooth type) and to examine the canal's morphological aspects (category, length, orifice position, and dentin width toward furcation). MATERIALS AND METHODS: The presence of MMC in the mesial roots of 505 mandibular molars of 200 patients was analyzed using cone-beam computed tomography (CBCT). Then, the position of the MMC orifices with respect to the pulpal floor and the main canals orifices, and the width of dentin along the canal toward the furcation were determined using 3D Slicer 4.10.1. RESULTS: In all, 14.65% of the first and second mandibular molars presented an MMC. A higher frequency of confluent canals was noted mostly joining the mesiobuccal canal (MBC). Gender appears to be a factor influencing the prevalence of MMCs, contrary to age-groups and tooth type. In mandibular first molars, the orifice is located at a mean distance of 1.22 ± 0.44 mm from the pulpal floor, 1.42 ± 0.53 mm from the MBC orifice, and 1.57 ± 0.60 mm from the mesiolingual canal (MLC) orifice. The width of dentin toward the furcation varies between 0.95 and 2.29 mm. In mandibular second molars, the orifice is located at a mean distance of 1.00 ± 0.51 mm from the pulpal floor, 1.39 ± 0.60 mm from the MBC orifice, and 1.37 ± 0.50 mm from MLC orifice. The width of dentin toward the furcation varies between 0.71 mm and 2.22 mm. CONCLUSION: Middle mesial canal is present in 14.65% of mandibular molars in the Lebanese population, with its orifice located under the pulpal floor. The majority of MMCs join the MBC. CLINICAL SIGNIFICANCE: Middle mesial canal is not a rare finding in the Lebanese population (14.65%). Clinicians should take time to search for this canal in the isthmus between the main mesial canals.