A new classification of cross-sectional root canal shape changes, a cone-beam computed tomography study

Abstract Background: The root canal system is considering the most important factor in endodontic treatment, due to the complexity of its anatomy and morphology. The aim of this study was to present a new classification of root canal shape changes in three thirds (coronal, middle, apical) in different age groups using cone-beam computed tomography scanning.Materials and methods: 300 CBCT scans for patient aged 20-70 were evaluated to study the morphology of the cross-sectional root canal shape in coronal, middle and apical thirds among three age groups; young (20-44), middle (45-59) and elderly (60-70). The root canal shape was classified as follow: round, oval, ribbon. Results: The cross-sectional root canal shape was identified in two groups: canals with an unchanging (constant) shape and canals with changing shape. In turn, in canals with changing shape, the change could be identified in the region of the middle or apical thirds of the canal. The results showed that root canal shape changes in two cases: 1) the presence of one or more canals in the root (with or without isthmus between them), 2) with age, as it was observed that the cross-sectional shape of the root canal becomes round in the apical third with age.Conclusion: A new classification of the changes of root canal shape in three thirds (coronal, middle, apical) was presented in this study.