Fig. 4From: Variations of root and canal morphology of mandibular second molars in Chinese individuals: a cone-beam computed tomography studyRoot and canal configuration of mandibular second molars with one root at different root levels. a one O-shaped root with one single root canal. b One O-C-shaped root with Taurodontism canal. c One C-shaped root with C-shaped root canal. (1) Canal orififice. (2) Coronal level. (3) Middle level. (4) Apical levelBack to article page