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 χ2 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.