Symmetry in root canal number and morphology between contralateral premolars and molars using cone-beam-computed-tomography

Aim: This study aimed to evaluate the symmetry of root canal number and morphology between opposite premolars and molars in each jaw using Cone-Beam Computed Tomography. Methods: 100 CBCT images of patients aged 18-65 were analyzed for diagnostic or therapeutic purposes. 96 premolars and mandibular molars, as well as 98 premolars and maxillary molars, were examined separately by two endo- and radiologists. Parameters such as canal numbers and root numbers in each root, and shape, and morphology of the canals were evaluated using NNT software. The symmetry of similar teeth in each jaw was also determined. Results: This study found that most mandibular premolars have one root and one canal with a type I Vertucci, while there are two roots and three canals in mandibular molars. Mostly, there is one root, two canals, and a type IV canal in maxillary premolars, while maxillary molars have three roots and three or four canals. The jaws have symmetry in terms of canal type, root numbers, and canal numbers. The mandible has greater symmetry than the maxilla in all cases. Conclusion: Assessing the symmetry of the canal numbers and premolars and molars morphology on both sides of each jaw using CBCT showed a significant correlation on both sides particularly between the first and second premolars and second molars, which can help dentists in comprehending root canal treatments and enhancing outcomes.