title: Dental CT evaluation of mandibular first premolar root configurations and canal variations.
abstract: OBJECTIVE
  Routine dental CT scans were used to describe mandibular first premolar root configurations and canal variations.
  
  
  METHODS
  One hundred twenty dental CT examinations were evaluated for mandibular first premolar root configurations and canal variations regarding shape of root and root canal, incidence of multiple canals, and level of bifurcation.
  
  
  RESULTS
  A total of 17 teeth in 12 patients showed mesial invagination of the root of the mandibular first premolar. One root displayed 3 canals with 3 apical foramina. In 2 teeth, a single canal divided into 2 canals, but merged into 1 apical foramen. One root showing 2 root canals finally divided into 2 roots near the apex. Thirteen roots had 2 canals and 2 apical foramina. The distance from the cementoenamel junction to the level of bifurcation was between 4 and 13 mm (mean, 7.4 mm).
  
  
  CONCLUSIONS
  The occurrence of incidentally found mandibular first premolar root variations should be an important component of dental CT reports.
authors.affiliation: Osteologie, University Klinik für Radiodiagnostik, Vienna, Austria.
authors.forename: Soraya
authors.initials: S
authors.lastname: Robinson
authors.forename: C
authors.initials: C
authors.lastname: Czerny
authors.forename: A
authors.initials: A
authors.lastname: Gahleitner
authors.forename: T
authors.initials: T
authors.lastname: Bernhart
authors.forename: F M
authors.initials: FM
authors.lastname: Kainberger
mesh_terms: D001641:Bicuspid / Q000000981:diagnostic imaging*; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging*; D006801:Humans; D008334:Mandible; D011862:Radiography, Panoramic; D014057:Tomography, X-Ray Computed; D014092:Tooth Root / Q000000981:diagnostic imaging*