Cone-beam CT study of the C-shaped root canal system in mandibular second permanent molars

Objective To study the incidence and the canal configuration of the C-shaped root canal of the mandibular second permanent molars. Methods CBCT images of 1164 mandibular second permanent molars were collected. The incidence and the canal configuration of the C-shaped canals were recorded. Results 39.95of the mandibular second permanent molars were C-shaped root canal. In these C-shaped root canal samples, 69.68were both-sides C-shaped root canal. The incidence of males and females were 33.14and 45.54%(P 0.001). The distribution of type-1, type-2 and type-3 in males and females were 41.76%, 28.57%, 29.67and 52.12%, 20.61%,27.27respectively(P 0.05). The incidence of the same type of the left-and-right side in males and females were51.35and 76.06%(P 0.001). Conclusion The application of the CBCT can help to facilitate root canal treatment.Mandibular second permanent molars commonly have a high prevalence for C-shaped root canal and both sides are symmetrical to some extent. Females are more likely to have C-shaped root canal.The incidence of the same type of the left-and-right side of females is much higher than males.The type-1 shows a higher prevalence.The incidence of the type-2 and type-3 shows no statistical significance.