Three-Dimensional Observation and Classification of Root and Root Canal Morphology in Japanese Mandibular Third Molars

This study aimed to collect the data on the roots and root canals of mandibular third molars of Japanese in order to provide diagnostic evidence for tooth transplantation by classifying their external root shape and root canal morphology. As specimens, 2,627 mandibular third molar teeth were used with computed tomography scanning and three-dimensional reconstruction. Of the 2,627 specimens, 1,444 were single root, and 1,183 were double root. Supernumerary roots were present in approximately 23.4% of all teeth, and the largest number of which had small root morphology and Type I root canal morphology. This study showed that most of the single and double roots had Type I root canal morphology, suggesting that the mandibular third molar is a reasonable choice as the donor tooth for tooth transplantation.