title: Analysis of C-shaped root canal configuration in maxillary molars in a Korean population using cone-beam computed tomography.
abstract: OBJECTIVE
  The purpose of this study was to investigate the incidence of root fusion and C-shaped root canals in maxillary molars, and to classify the types of C-shaped canal by analyzing cone-beam computed tomography (CBCT) in a Korean population.
  
  
  METHODS
  Digitized CBCT images from 911 subjects were obtained in Chosun University Dental Hospital between February 2010 and July 2012 for orthodontic treatment. Among them, a total of selected 3,553 data of maxillary molars were analyzed retrospectively. Tomography sections in the axial, coronal, and sagittal planes were displayed by PiViewstar and Rapidia MPR software (Infinitt Co.). The incidence and types of root fusion and C-shaped root canals were evaluated and the incidence between the first and the second molar was compared using Chi-square test.
  
  
  RESULTS
  Root fusion was present in 3.2% of the first molars and 19.5% of the second molars, and fusion of mesiobuccal and palatal root was dominant. C-shaped root canals were present in 0.8% of the first molars and 2.7% of the second molars. The frequency of root fusion and C-shaped canal was significantly higher in the second molar than the first molar (p < 0.001).
  
  
  CONCLUSIONS
  In a Korean population, maxillary molars showed total 11.3% of root fusion and 1.8% of C-shaped root canals. Furthermore, root fusion and C-shaped root canals were seen more frequently in the maxillary second molars.
authors.affiliation: Department of Conservative Dentistry, School of Dentistry, Chosun University, Gwangju, Korea.
authors.forename: Hyoung-Hoon
authors.initials: HH
authors.lastname: Jo
authors.affiliation: Department of Conservative Dentistry, School of Dentistry, Chosun University, Gwangju, Korea.
authors.forename: Jeong-Bum
authors.initials: JB
authors.lastname: Min
authors.affiliation: Department of Conservative Dentistry, School of Dentistry, Chosun University, Gwangju, Korea.
authors.forename: Ho-Keel
authors.initials: HK
authors.lastname: Hwang
keywords: C-shaped root canal; Cone-beam computed tomography; Korean; Maxillary molars; Root fusion