title: Assessing agreement in measurements of orthodontic study models: Digital caliper on plaster models vs 3-dimensional software on models scanned by structured-light scanner.
abstract: BACKGROUND
  In this study we aimed to compare measurements on plaster models using a digital caliper, and on 3-dimensional (3D) digital models, produced using a structured-light scanner, using 3D software.
  
  
  METHODS
  Fifty digital models were scanned from the same plaster models. Arch and tooth size measurements were made by 2 operators, twice. Calibration was done on 10 sets of models and checked using the Pearson correlation coefficient. Data were analyzed by error variances, repeatability coefficient, repeated-measures analysis of variance, and Bland-Altman plots.
  
  
  RESULTS
  Error variances ranged between 0.001 and 0.044 mm for the digital caliper method, and between 0.002 and 0.054 mm for the 3D software method. Repeated-measures analysis of variance showed small but statistically significant differences (P <0.05) between the repeated measurements in the arch and buccolingual planes (0.011 and 0.008 mm, respectively). There were no statistically significant differences between methods and between operators. Bland-Altman plots showed that the mean biases were close to zero, and the 95% limits of agreement were within ±0.50 mm. Repeatability coefficients for all measurements were similar.
  
  
  CONCLUSIONS
  Measurements made on models scanned by the 3D structured-light scanner were in good agreement with those made on conventional plaster models and were, therefore, clinically acceptable.
authors.affiliation: Senior lecturer, Department of Paediatric Dentistry and Orthodontics and Clinical Craniofacial Dentistry Research Group, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia. Electronic address: wannurazreena@um.edu.my.
authors.forename: Wan Nurazreena
authors.initials: WN
authors.lastname: Wan Hassan
authors.affiliation: Associate professor, Department of Paediatric Dentistry and Orthodontics and Clinical Craniofacial Dentistry Research Group, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Siti Adibah
authors.initials: SA
authors.lastname: Othman
authors.affiliation: Senior lecturer, Department of Artificial Intelligence, Faculty of Computer Science and Information Technology, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Chee Seng
authors.initials: CS
authors.lastname: Chan
authors.affiliation: Research assistant, Department of Paediatric Dentistry and Orthodontics and Clinical Craniofacial Dentistry Research Group, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Roshahida
authors.initials: R
authors.lastname: Ahmad
authors.affiliation: Research student, Department of Paediatric Dentistry and Orthodontics, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Siti Nor'Ain
authors.initials: SN
authors.lastname: Ali
authors.affiliation: Research student, Department of Paediatric Dentistry and Orthodontics, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Anis
authors.initials: A
authors.lastname: Abd Rohim
mesh_terms: D003198:Computer Simulation; D054893:Cone-Beam Computed Tomography; D003724:Dental Arch / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D006801:Humans; D021621:Imaging, Three-Dimensional; D003765:Models, Dental; D009811:Odontometry / Q000295:instrumentation; D012984:Software; D014070:Tooth / Q000033:anatomy & histology / Q000000981:diagnostic imaging