Evaluation of roots and root canals' morphology of maxillary premolars in a Syrian subpopulation using cone-beam computed tomography

Introduction: The morphology of the roots is variable and complex; hence, a better understanding of the root canal systems is important to provide optimal endodontic treatment. The aim of this study was to investigate the number of roots, and root canals' morphology of the first and second premolars in the Syrian subpopulation, and their bilateral symmetry. In addition, it aimed at exploring the effect of gender on the morphological aspects. Materials and Methods: Two hundred and fifty cone-beam computed tomography (CBCT) images (140 images for females, 110 images for males) were collected and examined by two endodontists. Details of the number of roots, number of canals, and canals' configurations in each root were recorded according to Vertucci classification by inspecting the CBCT images in all levels (axial, coronal, sagittal, oblique, and three dimensional). The Chi-square statistical analysis was performed to compare the canals' morphologies and bilateral symmetry in both genders. Results: While most of the first premolars had two roots (59.2%), the majority of second premolars (80.8%) had one root. The highest proportions within the first and second premolars (41.8 and 36.1%) had Vertucci Type-II configuration. The ratios symmetry of maxillary first and second premolars for the number of roots were 90.4% and 93.6%, respectively, and for the number of canals were 94.4% and 90.4%, respectively. There was no significant difference in the proportion of symmetry for both genders in the first and second premolars regarding the number of roots and the number of canals (P > 0.05). Conclusions: While most maxillary first premolars were two-rooted with two root canals, maxillary second premolars tended to be single-rooted with two root canals; males had a greater number of roots than females. While maxillary second premolars exhibited greater bilateral symmetry in the number of roots than maxillary first premolars, the latter exhibited greater bilateral symmetry than maxillary second premolars in the number of root canals.