Assessment of root canal morphology of maxillary and mandibular second molars in the Iranian population using CBCT

Background. Inability to efficiently clean all root canals due to the complex anatomy of the root canal system is a common cause of endodontic treatment failure. Objectives. This study aimed to assess the root canal morphology of the maxillary and mandibular second molars using cone-beam computed tomography (CBCT). Material and methods. This descriptive study evaluated 502 CBCT scans taken in the years 2014-2017. The number of roots and canals, type of canals according to the Vertucci classification, presence of maxillary second molars with 2 palatal roots, and C-shaped canals in the maxillary and mandibular second molars were evaluated on CBCT scans separately by a radiologist and 2 endodontists. The data was analyzed using SPSS via descriptive statistics, Fisher's exact test, the independent samples t-test, and the chi(2) test. All the analyses were performed with a confidence level of 95%. Results. The majority of the palatal, mesiobuccal and distobuccal roots of the maxillary second molars had 1 single canal of Vertucci type I; 21.5% of the mesiobuccal roots had a second mesiobuccal canal (p = 0.05). Conclusions. Two-rooted mandibular second molars and 3-rooted maxillary second molars were the most common in our study population. Cone-beam computed tomography as a non-invasive and highly accurate imaging modality is efficacious for the detection of additional roots and C-shaped canals.