title: Evaluation of transversal slice imaging in the diagnosis of tooth displacement with special consideration of the upper canines.
abstract: OBJECTIVE
  The exact localization and analysis of displaced, retained or impacted teeth can rarely be achieved by common radiologic methods providing eccentric or occlusal images. The aim of this study was to evaluate transversal slice imaging (TSI) as a diagnostic alternative, keeping radiation exposure under consideration.
  
  
  METHODS
  In a pilot study, we simulated seven different canine positions in a phantom head. Each tooth position was visualized by transversal slice imaging and compared by several observers independently and blinded to computer tomography (CT) serving as the gold standard. The clinical study included the retrospective analysis of TSI samples from 27 patients (mean age 13.7 yrs.) according to these criteria: 1. location of the canine crown and root, 2. recognition of the crown, 3. stage of root development, 4. root dilaceration, 5. periodontal ligament space, 6. ankylosis, 7. relationship to neighboring teeth, and 8. resorptions of neighboring teeth. The evaluations of canine position were compared to the results gained intraoperatively.
  
  
  RESULTS
  In the transversal slice images taken from a phantom head, the observers' estimations of the canine position were identical in five cases (71.4%). At least four observers using TSI described identical tooth positions in 89% of patients. In 2.5%, no statement concerning tooth position was feasible. Crown recognition was possible in 75% of cases. Ankylosis, periodontal ligament space, root development, dilacerations and resorptions were not assessable in the majority of the cases.
  
  
  CONCLUSIONS
  Transversal slice imaging can be recommended as a second plane projection in diagnosing tooth displacement, especially concerning oro-vestibular localization (effective radiation dose 0.003-0.012 mSv). However, as far as periodontal ligament space, resorptions and root morphology are concerned, this method has its limits.
authors.affiliation: Department of Orthodontics, University Hospital, Hamburg-Eppendorf, Germany. ninabroer@yahoo.com
authors.forename: Nina
authors.initials: N
authors.lastname: Broer
authors.forename: Andreas
authors.initials: A
authors.lastname: Fuhrmann
authors.forename: Silke
authors.initials: S
authors.lastname: Bremert
authors.forename: Dirk
authors.initials: D
authors.lastname: Schulze
authors.forename: Bärbel
authors.initials: B
authors.lastname: Kahl-Nieke
mesh_terms: D000293:Adolescent; D019412:Anatomy, Cross-Sectional / Q000379:methods*; D003481:Cuspid / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D019047:Phantoms, Imaging; D010865:Pilot Projects; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011862:Radiography, Panoramic / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods; D014084:Tooth Avulsion; D014086:Tooth Mobility / Q000000981:diagnostic imaging*