2023 Volume 14 Issue 1 Pages 16-25
The difficulty of root canal treatment in the mandibular first molars is related to the complexity of their root canal structure. Therefore, knowledge of root and root canal anatomy is important. In this study, the mesial and distal root canal morphologies were analyzed based on Vertucci’s classification. In addition, distolingual root (DLR) may occur as a variation of mandibular first molars. Distolingual (DL) root canals exhibit a severe buccal curve. Curved root canals may be a cause of root canal treatment failure. Ways to prevent root canal treatment failure were investigated by analyzing the frequency of DLR prevalence and the curvature of DL root canals. The DLR frequency was approximately 30% in both male and female. The DLR frequency in the Japanese population was found to be close to that of the Sinodonty in the Mongoloid populations, indicating a high frequency. Mesial root canals were most frequently type 4, whereas distal, distobuccal (DB), and DL root canals were most frequently type 1, similar to those in other studies. There was a significant difference in the incidence of type 1 between distal and DB, distal and DL root canal in both males and females. When a DLR was present, DB and DL root canals were thought to simplify to one root canal (type 1). The angles measured by Schneider’s method were close to the results of other studies in both males and females. However, the angles and radii measured by Pruett’s method were smaller than the results of other studies, suggesting that the DLR of the Japanese population may have a severe curve. Therefore, it was suggested that root canal treatment of DLR should be performed with caution.
