title: [Cross-sectional morphology and wall thickness of the root canal system in mandibular first premolars with C-shaped root evaluated by cone-beam CT].
abstract: OBJECTIVE
  To analyze the cross-sectional morphology of the root canal system in mandibular first premolars with C-shaped root and measure the minimum canal wall thickness.
  
  
  METHODS
  44 mandibular first premolars with C-shaped root were selected. The specimens were scanned by cone-beam computed tomography and 3D images of each specimen were reconstructed. The distribution of cross-sectional morphology of root canals in different portion of the roots was analyzed and compared. And measurement of the minimum canal wall thickness in the radicular groove aspect and the opposite aspect in different portion of the roots was taken. SPSS13.0 software package was used to perform the statistical analysis.
  
  
  RESULTS
  The distribution of cross-sectional morphology of root canals was complex in the middle 1/3 and apical 1/3, mainly in types C2, C3 and C4, which was different from that of cervical 1/3(P<0.05). The minimum canal wall thickness in the radicular groove aspect was thinner than that in the opposite aspect of both middle 1/3 and apical 1/3(P<0.05). And the value of the minimum canal wall thickness in both middle 1/3 and apical 1/3 was less than 1mm.
  
  
  CONCLUSIONS
  Morphology of root canals in mandibular first premolars with C-shaped root was complex in apical 2/3 of the roots and the canal wall thickness was thinner in the radicular groove aspect. These factors should be considered in clinical treatment.
authors.affiliation: Department of Endodontics, Wenzhou Medical College, Wenzhou, Zhejiang Province, China. endo_lijun@yahoo.com.cn
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Ling
authors.initials: L
authors.lastname: Li
mesh_terms: D001641:Bicuspid; D054893:Cone-Beam Computed Tomography; D003430:Cross-Sectional Studies; D003786:Dental Pulp Cavity; D006801:Humans; D021621:Imaging, Three-Dimensional; D008334:Mandible; D009333:Neck; D012390:Root Canal Therapy; D014092:Tooth Root