title: Mandibular first molar with six separate canals.
abstract: BACKGROUND
  Many anatomical variations can occur within the mandibular first molar. Commonly, 3-4 canals are located, but as many as 6-7 canals have been reported.
  
  
  METHODS
  This report describes a case of a mandibular first molar with 6 separate canals (3 mesial and 3 distal) that was instrumented with conventional hand and rotary files and obturated by using a hybrid warm vertical compaction technique.
  
  
  RESULTS
  Recall examination as far as 3 years post-treatment found no sensitivity to percussion or palpation and recall radiographs after treatment show resolution of the previous apical periodontitis.
  
  
  CONCLUSIONS
  The existence of such teeth as these underlies the importance of looking for additional canals.
authors.affiliation: Department of Restorative Sciences, Division of Endodontics, University of Minnesota School of Dentistry, 8-166 Moos Tower, 515 Delaware Street SE, Minneapolis, MN 55455, USA. bowle001@umn.edu
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Ryan
authors.forename: Walter R
authors.initials: WR
authors.lastname: Bowles
authors.forename: Michael K
authors.initials: MK
authors.lastname: Baisden
authors.forename: Scott B
authors.initials: SB
authors.lastname: McClanahan
mesh_terms: D003786:Dental Pulp Cavity / Q000002:abnormalities*; D003790:Dental Pulp Necrosis / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D006171:Gutta-Percha / Q000627:therapeutic use; D006801:Humans; D008334:Mandible; D008875:Middle Aged; D008963:Molar / Q000002:abnormalities*; D010485:Periapical Periodontitis / Q000628:therapy; D016300:Radiography, Bitewing; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D012389:Root Canal Obturation / Q000379:methods; D018915:Root Canal Preparation / Q000379:methods
chemical_list: D012387:Root Canal Filling Materials; D006171:Gutta-Percha