title: Root and root canal morphology in maxillary second molar with fused root from a native Chinese population.
abstract: BACKGROUND
  Root fusion is an anatomic variation in maxillary second molars (MSMs); however, the nature of this canal morphology as it relates to its root anatomy has not been fully clarified. The purpose of this study was to investigate the relationship between features of fused roots and root canal anatomy in MSMs using micro-computed tomographic imaging.
  
  
  METHODS
  One hundred eighty-seven extracted MSMs were scanned with the μCT50 (Scanco Medical, Bassersdorf, Switzerland), and their root and canal morphology was classified and analyzed using the classifications proposed by Yang and Vertucci. The number and position of canals that merged were recorded and compared among different root fusion types.
  
  
  RESULTS
  One hundred eight (57.75%) MSMs had 3 separate roots, and 79 (42.25%) had fused roots. Of the 79 fused roots, 22 showed partial canal merging, and 6 had complete canal merging. Canal merging was found with teeth with 3-root fusion more often than in those with 2-root fusion (P < .05). Of 28 merged canals, 16 occurred between mesiobuccal and distobuccal canals and 9 among mesiobuccal, distobuccal, and palatal canals.
  
  
  CONCLUSIONS
  MSMs with fused roots may present a complicated root canal system as a result of canal merging.
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Qiyuan
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China. Electronic address: bingfan8@hotmail.com.
authors.forename: Bing
authors.initials: B
authors.lastname: Fan
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Fan
authors.affiliation: Department of Endodontics, Baylor College of Dentistry, Texas A&M University System Health Science Center, Dallas, Texas.
authors.forename: James L
authors.initials: JL
authors.lastname: Gutmann
mesh_terms: D063405:Anatomic Variation; D002681:China; D003786:Dental Pulp Cavity / Q000002:abnormalities* / Q000000981:diagnostic imaging; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008437:Maxilla; D008963:Molar / Q000002:abnormalities* / Q000000981:diagnostic imaging; D019227:Tooth Apex / Q000000981:diagnostic imaging; D019237:Tooth Cervix / Q000000981:diagnostic imaging; D014092:Tooth Root / Q000002:abnormalities* / Q000000981:diagnostic imaging; D055114:X-Ray Microtomography / Q000379:methods
keywords: Fused root; maxillary second molar; morphology; root canal