title: Cone beam computed tomography for assessment of root length and marginal bone level during orthodontic treatment.
abstract: OBJECTIVE
  To evaluate the accuracy and precision of cone beam computed tomography (CBCT) with regard to measurements of root length and marginal bone level in vitro and in vivo during the course of orthodontic treatment.
  
  
  METHODS
  Thirteen patients (aged 12-18 years) from an ongoing study and a dry skull were examined with CBCT using multiplanar reformatting for measurements of root length and marginal bone level. For in vivo evaluation of changes in root length, an index according to Malmgren et al was used, along with a modification of this method.
  
  
  RESULTS
  The in vitro mean difference between physical and radiographic measurements was 0.05 mm (SD 0.75) for root length and -0.04 mm (SD 0.54) for marginal bone level. In vivo the error was <0.35 mm for root length determinations and <0.40 mm for marginal bone level assessments.
  
  
  CONCLUSIONS
  Despite changes in tooth positions, the CBCT technique yields a high level of reproducibility, enhancing its usefulness in orthodontic research.
authors.affiliation: Department of Oral and Maxillofacial Radiology, University of Gothenburg, Sweden. Henrik.Lund@vgregion.se
authors.forename: Henrik
authors.initials: H
authors.lastname: Lund
authors.forename: Kerstin
authors.initials: K
authors.lastname: Gröndahl
authors.forename: Hans-Göran
authors.initials: HG
authors.lastname: Gröndahl
mesh_terms: D000293:Adolescent; D000539:Alveolar Process / Q000000981:diagnostic imaging* / Q000473:pathology; D002508:Cephalometry / Q000379:methods; D002648:Child; D054893:Cone-Beam Computed Tomography / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008311:Malocclusion, Angle Class I / Q000000981:diagnostic imaging / Q000628:therapy; D009811:Odontometry / Q000379:methods; D009967:Orthodontic Appliances; D009971:Orthodontics, Corrective; D011856:Radiographic Image Enhancement; D015203:Reproducibility of Results; D012391:Root Resorption / Q000000981:diagnostic imaging / Q000473:pathology; D012690:Serial Extraction; D019227:Tooth Apex / Q000000981:diagnostic imaging / Q000473:pathology; D014092:Tooth Root / Q000000981:diagnostic imaging* / Q000473:pathology