title: Maxillary premolar with 4 separate canals.
abstract: BACKGROUND
  Recognition of anatomic variations is a challenge for clinicians regardless of which tooth is treated. Maxillary premolars usually have 2 root canals, but the presence of 3 distinct root canals has been reported in 1%-6% of cases.
  
  
  RESULTS
  This report describes the case of a maxillary right second premolar with 4 separate canals: 1 mesial, 1 palatal, and 2 distal canals. This was confirmed by using cone-beam computed tomography and was successfully treated with rotary files and obturated by using a warm vertical compaction technique.
  
  
  CONCLUSIONS
  The clinical significance of the present case is that this is the first report of 3 roots and 4 separate canals in a maxillary premolar. Precise knowledge of root canal morphology and its variation is also underlined. Cone-beam computed tomography examination and the operating microscope are excellent tools for identifying and managing these complex root canal systems.
authors.affiliation: Private Practice, New York, New York.
authors.forename: Carina
authors.initials: C
authors.lastname: Lea
authors.affiliation: Private Practice, New York, New York.
authors.forename: Jason
authors.initials: J
authors.lastname: Deblinger
authors.affiliation: Endodontics Division, São Paulo University, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Machado
authors.affiliation: Health Sciences Center, Grande Rio University (UNIGRANRIO), Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: nogueiraemmanuel@hotmail.com.
authors.forename: Emmanuel João
authors.initials: EJ
authors.lastname: Nogueira Leal Silva
authors.affiliation: Endodontics Division, São Paulo University, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Luiz Pascoal
authors.initials: LP
authors.lastname: Vansan
mesh_terms: D000328:Adult; D063405:Anatomic Variation; D001641:Bicuspid / Q000000981:diagnostic imaging*; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging*; D005260:Female; D005500:Follow-Up Studies; D006171:Gutta-Percha / Q000627:therapeutic use; D006801:Humans; D008437:Maxilla / Q000000981:diagnostic imaging; D008866:Microsurgery / Q000295:instrumentation; D010485:Periapical Periodontitis / Q000000981:diagnostic imaging; D011671:Pulpitis / Q000000981:diagnostic imaging; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D012389:Root Canal Obturation / Q000379:methods; D018915:Root Canal Preparation / Q000295:instrumentation; D014092:Tooth Root / Q000000981:diagnostic imaging; D014098:Toothache / Q000000981:diagnostic imaging; D015035:Zinc Oxide-Eugenol Cement / Q000627:therapeutic use
chemical_list: D012387:Root Canal Filling Materials; D015035:Zinc Oxide-Eugenol Cement; C074935:Roth's 801 Sealer; D006171:Gutta-Percha
keywords: Anatomy; CBCT; maxillary premolar