title: The use of spiral computed tomography in the localization of impacted maxillary canines.
abstract: OBJECTIVE
  To compare spiral CT with conventional radiography in planning the orthodontic treatment of impacted permanent maxillary canines.
  
  
  METHODS
  Nineteen patients with 29 malpositioned permanent maxillary canines (15 palatal and 12 buccal impactions, one ectopic and one transposition) were examined with conventional panoramic and lateral cephalometric radiography and with spiral CT (at 1 mm slice thickness, and 1:1 or 2:1 pitch) using multiplanar (MPR) and 3D reconstruction.
  
  
  RESULTS
  Conventional radiography failed to depict root resorption especially on the buccal surfaces of the incisor teeth. CT located impacted teeth better. Contact between impacted maxillary canines and incisor roots was demonstrated in 26 cases and root resorption in eight. MPR proved to be superior for the orientation of impacted teeth, and, in two cases, confirmed the presence of minimal root lesions for which axial images had proved inconclusive. The 3D reconstructions were useful in targeting the MPR.
  
  
  CONCLUSIONS
  CT facilitates the treatment of impacted canine especially when the teeth are very oblique to the arch. Root resorption is better demonstrated especially on the palatal and buccal surfaces of the adjacent incisors. Spiral CT reduces examination time and risk of accidental movement, thus optimizing MPR quality. Examination at 2:1 pitch enables a significant reduction in radiation exposure without loss of image quality.
authors.affiliation: Institute of Radiology, University of Pavia, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Preda
authors.forename: A
authors.initials: A
authors.lastname: La Fianza
authors.forename: E M
authors.initials: EM
authors.lastname: Di Maggio
authors.forename: R
authors.initials: R
authors.lastname: Dore
authors.forename: M R
authors.initials: MR
authors.lastname: Schifino
authors.forename: R
authors.initials: R
authors.lastname: Campani
authors.forename: C
authors.initials: C
authors.lastname: Segù
authors.forename: M F
authors.initials: MF
authors.lastname: Sfondrini
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003481:Cuspid; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla; D011856:Radiographic Image Enhancement; D011862:Radiography, Panoramic; D012391:Root Resorption / Q000000981:diagnostic imaging / Q000209:etiology; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014095:Tooth, Impacted / Q000150:complications / Q000000981:diagnostic imaging*