Root and canal configurations of mandibular molars using CBCT, with an emphasis on middle mesial canals

Abstract

Introduction: An extensive knowledge of dental root and canal anatomy is essential to clinicians performing endodontic treatment. It is well-known that dental anatomy may be complex and display significant variation. Aim: The aim of the present study was to classify the root number and the root canal configurations of human mandibular first and second molars in a South African sub-population using CBCT. Materials and methods: The study design was a retrospective cross-sectional descriptive study. The sample size included 753 molars. The CBCT images of each individual mandibular first and second molar were evaluated in coronal, sagittal and axial views. Classification of the canal configurations of each root was made using the Vertucci classification system, including the additions proposed by Sert and Bayirli. Classification of root number was described as one, two, three, or four-roots. Results: Root anatomy: Two-rooted configurations were demonstrated in the majority of first and second molars (98.7% and 94%). One- and three-rooted molars were rare with a prevalence ranging from 0.3% to 2.9%. Half of all three-rooted molars presented with two distinct mesial roots. Four-rooted molars were found in second molars only (0.5%). Canal anatomy: The most common canal type in the mesial roots of mandibular first and second molars was Type IV (50% and 38%) followed by Type II (21% and 24%). The most common canal configuration in the distal roots of the first and second molars was Type I (50% and 81%) followed by Type V (20% and 10%). More than two mesial canals in mandibular first and second molars were present in 21% and 17% of the sample. More than two distal canals were demonstrated in first and second molars in 7% and 2% of the sample. C-shaped canal systems were found in 0.5% of first molars and 7.7% of second molars. Sex and age had no correlation to root or canal configurations. Conclusion: More than two mesial canals were found in about one-fifth of the sample. It is important for clinicians to be aware that a number of mandibular molars may present with more intricate anatomy than expected during endodontic treatment and that this may affect treatment outcomes.