title: Digital tooth-based superimposition method for assessment of alveolar bone levels on cone-beam computed tomography images.
abstract: BACKGROUND
  Cone-beam computed tomography images have been previously used for evaluation of alveolar bone levels around teeth before, during, and after orthodontic treatment. Protocols described in the literature have been vague, have used unstable landmarks, or have required several software programs, file conversions, or hand tracings, among other factors that could compromise the precision of the measurements. The purposes of this article are to describe a totally digital tooth-based superimposition method for the quantitative assessment of alveolar bone levels and to evaluate its reliability.
  
  
  METHODS
  Ultra cone-beam computed tomography images (0.1-mm reconstruction) from 10 subjects were obtained from the data pool of the University of Oklahoma; 80 premolars were measured twice by the same examiner and a third time by a second examiner to determine alveolar bone heights and thicknesses before and more than 6 months after orthodontic treatment using OsiriX (version 3.5.1; Pixeo, Geneva, Switzerland). Intraexaminer and interexaminer reliabilities were evaluated, and Dahlberg's formula was used to calculate the error of the measurements.
  
  
  RESULTS
  Cross-sectional and longitudinal evaluations of alveolar bone levels were possible using a digital tooth-based superimposition method. The mean differences for buccal alveolar crest heights and thicknesses were below 0.10 mm for the same examiner and below 0.17 mm for all examiners. The ranges of errors for any measurement were between 0.02 and 0.23 mm for intraexaminer errors, and between 0.06 and 0.29 mm for interexaminer errors.
  
  
  CONCLUSIONS
  This protocol can be used for cross-sectional or longitudinal assessment of alveolar bone levels with low interexaminer and intraexaminer errors, and it eliminates the use of less reliable or less stable landmarks and the need for multiple software programs and image printouts. Standardization of the methods for bone assessment in orthodontics is necessary; this method could be the answer to this need.
authors.affiliation: Clinical assistant professor, Department of Orthodontics, Health Sciences Center, University of Oklahoma, Oklahoma City, Okla. Electronic address: alejandro-romerodelmastro@ouhsc.edu.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Romero-Delmastro
authors.affiliation: Graduate program director and assistant professor, Department of Orthodontics, Health Sciences Center, University of Oklahoma, Oklahoma City, Okla.
authors.forename: Onur
authors.initials: O
authors.lastname: Kadioglu
authors.affiliation: Chair and professor, Department of Orthodontics, Health Sciences Center, University of Oklahoma, Oklahoma City, Okla.
authors.forename: G Frans
authors.initials: GF
authors.lastname: Currier
authors.affiliation: Graduate research assistant and postgraduate student, Department of Orthodontics, Health Sciences Center, University of Oklahoma, Oklahoma City, Okla.
authors.forename: Tanner
authors.initials: T
authors.lastname: Cook
mesh_terms: D000293:Adolescent; D000539:Alveolar Process / Q000000981:diagnostic imaging*; D001641:Bicuspid / Q000000981:diagnostic imaging*; D002508:Cephalometry / Q000379:methods / Q000706:statistics & numerical data; D002648:Child; D054893:Cone-Beam Computed Tomography / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods* / Q000706:statistics & numerical data; D021621:Imaging, Three-Dimensional / Q000379:methods / Q000706:statistics & numerical data; D015588:Observer Variation; D009811:Odontometry / Q000379:methods / Q000706:statistics & numerical data; D009971:Orthodontics, Corrective; D015203:Reproducibility of Results