title: [Morphology of cross-sectioned root canal in Chinese mandibular permanent incisors].
abstract: OBJECTIVE
  To identify morphological features of cross-sectioned root canal in Chinese mandibular permanent incisors.
  
  
  METHODS
  Twenty mandibular permanent incisors were selected in this study. The tooth roots were embedded in resin and transversely sectioned with a low-speed diamond saw. The number of root canal and the morphology and isthmus of the root canal were observed under a stereo-microscope, which included the measure of the canal diameter.
  
  
  RESULTS
  The double root canal comprised 22.5%, 30.0%, and 15.0% in crown third, middle third, and apical third root canals of the mandibular permanent incisors, respectively. The long oval canal comprised 44.8%, 77.0%, and 44.5% in crown third, middle third, and apical third root canals, respectively. The canal isthmus comprised 62.5%, 75.0%, and 48.7% in crown third, middle third, and apical third root canals, respectively. The diameter of buccal-lingual canal was at least 2 times of the diameter of mesial-distal canal.
  
  
  CONCLUSIONS
  The cross-sectioned root canal morphology in Chinese mandibular permanent incisors varies considerably. But most have long oval and canal isthmus, which imposes a great challenge for root canal therapy.
authors.affiliation: Department of Conservative Dentistry, West China School of Stomatology, Sichuan University, Chengdu 610041, China.
authors.forename: Ding-Ming
authors.initials: DM
authors.lastname: Huang
authors.forename: Yu-Qing
authors.initials: YQ
authors.lastname: Hao
authors.forename: Shi-Gao
authors.initials: SG
authors.lastname: Luo
authors.forename: Liu-He
authors.initials: LH
authors.lastname: Jia
authors.forename: Xue-Dong
authors.initials: XD
authors.lastname: Zhou
mesh_terms: D019412:Anatomy, Cross-Sectional; D044466:Asian People; D002681:China; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology*; D008297:Male; D008334:Mandible / Q000033:anatomy & histology*