title: A cone-beam computed tomography study of maxillary first permanent molar root and canal morphology in a Chinese population.
abstract: OBJECTIVE
  This study evaluated root and canal morphology of permanent maxillary first molars in a Chinese population using cone-beam computed tomography scanning.
  
  
  METHODS
  The sample included 775 cone-beam computed tomography images of maxillary first molars; 627 of the subjects had unilateral qualifying molars and 74 had bilateral qualifying molars. The following observations were made: (1) frequency of root and canal numbers, (2) frequency of additional canals in the mesiobuccal root by sex, age, and tooth position, and (3) unilateral and bilateral occurrence of additional canals in the mesiobuccal root.
  
  
  RESULTS
  Fused roots were present in 2.71% of unilateral qualifying molars. Multiple canals were present in the following frequencies: two canals in 0.31%, three canals in 47.21%, four canals in 50.40%, five canals in 1.75%, and six canals in 0.31% of teeth. Additional canals were detected in 52.24% of mesiobuccal roots, 1.12% of distobuccal roots, and 1.76% of palatal roots. Patients aged 20 to 30 years showed a higher prevalence of additional mesiobuccal root canals. This prevalence did not differ with sex and tooth position. Most (71.11%) of the additional mesiobuccal root canals in subjects with bilateral qualifying molars were symmetric.
  
  
  CONCLUSIONS
  Cone-beam computed tomography scanning is an effective method for studying external and internal dental morphology. The root and canal configurations of maxillary first molars in this Chinese population were consistent with previously reported data. More attention should be given to the detection of additional canals in patients between 20 and 30 years of age. These data may facilitate successful endodontic treatment.
authors: State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China.
authors: Qing-hua
authors: QH
authors: Zheng
authors: Yao
authors: Y
authors: Wang
authors: Xue-dong
authors: XD
authors: Zhou
authors: Qian
authors: Q
authors: Wang
authors: Guang-ning
authors: GN
authors: Zheng
authors: Ding-ming
authors: DM
authors: Huang
mesh_terms: D000293:Adolescent; D000368:Aged; D044466:Asian People / Q000706:statistics & numerical data; D002648:Child; D002681:China; D054893:Cone-Beam Computed Tomography; D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla; D008875:Middle Aged; D008963:Molar / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D012016:Reference Values; D014092:Tooth Root / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D055815:Young Adult