Morphometric analysis of the root canal system in three-rooted mandibular first molars: a micro-CT study in a Malaysian subpopulation

Three-rooted mandibular molars show wide variations in the root and canal anatomy. This study aimed to investigate the root canal configuration, the prevalence and location of accessory canals in three-rooted mandibular first molars in the Malaysian subpopulation using micro-computed tomography (micro-CT). A total of 70 extracted three-rooted mandibular first molars were collected from various dental clinics in selected Malaysian states; patient ethnicity, age, and gender were not recorded. The collected teeth were scanned using micro-CT. The segmentation and 3D reconstruction of the acquired images were done using MIMICS software. Vertucci et al. (1974) and Ahmed et al. (2017) systems were used to classify the root canal configuration. The location and type of accessory canals were classified using complementary system introduced by Ahmed et al. (2018). Chi-square test was used for data analysis ( p = 0.05). Results showed that Vertucci Type I was the most commonly recorded configuration in mesial (12.9%), distal (92.9%), and distolingual (100%) roots, while 50% of the reported configurations in mesial root were non-classifiable by Vertucci system. According to Ahmed et al. coding system, the most recorded code for the mesial, distal, and distolingual roots was M 1 , D 1 , and DL 1 , respectively. The most predominantly identified code for the tooth was 3 MFM M 1 D 1 DL 1 (11.4%), followed by the 3 MFM M 1–2 D 1 DL 1 (7.1%). The Ahmed et al. coding system was able to classify all canals in the mesial root. The chi-square test revealed a significant association between root type and root canal configuration ( p < 0.001) in both systems. The accessory canals were recorded in 92.9% of the samples, these were predominantly located in the apical third (86.9%), with the patent type being the most frequently encountered (66.3%). Three-rooted mandibular first molars in the studied Malaysian subpopulation demonstrate a wide range of variations in root canal configuration with high prevalence of accessory canals. In comparison to the Vertucci system, the coding system developed by Ahmed et al. provides a precise and practical classification of all canals, irrespective to their complexity.