Cone-Beam Computed Tomography Analysis of the Root Canal Morphology of Lower Second Molars in the Croatian Subpopulation

The aim of this study was to investigate the root canal morphology of lower second molars in the Croatian subpopulation of the Zagreb region using cone-beam computed tomography (CBCT). We analyzed 3212 CBCT scans from the two radiology centers in Zagreb. The number of roots and root canals, the occurrence of C-shaped canals and additional roots were recorded. “C”-shaped roots were classified according to Melton classification. Canals in the mesial root were classified according to Vertucci. Lower second molars were found on 608 CBCT scans from a total number of 859. Among them, 78 (9.1%) had a “C”-shaped form. In the mesial roots, the frequencies of Vertucci types were: Type I in ninety-four cases (12.0%), Type II in three hundred and twenty cases (41.0%), Type III in six cases (0.8%), Type IV in three hundred and fifty-two cases (45.1%), Type V in three cases (0.4%), Type VI was found in four cases (0.5%) and Type VIII was found in one case (0.1%). Radix entomolaris and paramolaris were found in 29 (3.4%) lower second molars. The lower second molars in the Zagreb population show significant diversity in internal anatomy with a relatively high prevalence of “C”-shaped root canals and merged root canals in the mesial root.