title: Reproducibility and accuracy of linear measurements on dental models derived from cone-beam computed tomography compared with digital dental casts.
abstract: BACKGROUND
  The aim of this study was to determine the reproducibility and accuracy of linear measurements on 2 types of dental models derived from cone-beam computed tomography (CBCT) scans: CBCT images, and Anatomodels (InVivoDental, San Jose, Calif); these were compared with digital models generated from dental impressions (Digimodels; Orthoproof, Nieuwegein, The Netherlands). The Digimodels were used as the reference standard.
  
  
  METHODS
  The 3 types of digital models were made from 10 subjects. Four examiners repeated 37 linear tooth and arch measurements 10 times. Paired t tests and the intraclass correlation coefficient were performed to determine the reproducibility and accuracy of the measurements.
  
  
  RESULTS
  The CBCT images showed significantly smaller intraclass correlation coefficient values and larger duplicate measurement errors compared with the corresponding values for Digimodels and Anatomodels. The average difference between measurements on CBCT images and Digimodels ranged from -0.4 to 1.65 mm, with limits of agreement values up to 1.3 mm for crown-width measurements. The average difference between Anatomodels and Digimodels ranged from -0.42 to 0.84 mm with limits of agreement values up to 1.65 mm.
  
  
  CONCLUSIONS
  Statistically significant differences between measurements on Digimodels and Anatomodels, and between Digimodels and CBCT images, were found. Although the mean differences might be clinically acceptable, the random errors were relatively large compared with corresponding measurements reported in the literature for both Anatomodels and CBCT images, and might be clinically important. Therefore, with the CBCT settings used in this study, measurements made directly on CBCT images and Anatomodels are not as accurate as measurements on Digimodels.
authors.affiliation: Postgraduate student, Department of Orthodontics and Craniofacial Biology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. Electronic address: orthodontics@dent.umcn.nl.
authors.forename: Olivier
authors.initials: O
authors.lastname: de Waard
authors.affiliation: Junior researcher, Department of Orthodontics and Craniofacial Biology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Frits Andreas
authors.initials: FA
authors.lastname: Rangel
authors.affiliation: Senior lecturer, Department of Orthodontics, University of Bern, Bern, Switzerland; associate professor, Palacky University, Olomouc, Czech Republic.
authors.forename: Piotr Stanislaw
authors.initials: PS
authors.lastname: Fudalej
authors.affiliation: Statistician/methodologist, Department of Preventive and Curative Dentistry, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Ewald Maria
authors.initials: EM
authors.lastname: Bronkhorst
authors.affiliation: Professor and chair, Department of Orthodontics and Craniofacial Biology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Kuijpers-Jagtman
authors.affiliation: Assistant professor, Department of Orthodontics and Craniofacial Biology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Karel Hero
authors.initials: KH
authors.lastname: Breuning
mesh_terms: D002508:Cephalometry / Q000706:statistics & numerical data; D054893:Cone-Beam Computed Tomography / Q000706:statistics & numerical data*; D003724:Dental Arch / Q000033:anatomy & histology; D003761:Dental Impression Technique / Q000706:statistics & numerical data; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data*; D021621:Imaging, Three-Dimensional / Q000706:statistics & numerical data; D003765:Models, Dental; D015203:Reproducibility of Results; D012984:Software; D013499:Surface Properties; D014070:Tooth / Q000033:anatomy & histology; D019228:Tooth Crown / Q000033:anatomy & histology