title: Accuracy and reproducibility of 3-dimensional digital model measurements.
abstract: BACKGROUND
  The purpose of this study was to evaluate the reliability of measurements made on 3-dimensional digital models obtained with a surface laser scanner (D-250; 3Shape, Copenhagen, Denmark).
  
  
  METHODS
  Twenty orthodontic dental casts of permanent dentitions were selected. Three-dimensional images were obtained on this scanner and analyzed by using the Geomagic Studio 5 software (Raindrop Geomagic, Inc, Morrisville, NC). Measurements were made with a digital caliper directly on the dental casts and also digitally on the digital models. Fifteen anatomic dental points were identified, and a total of 11 linear measurements were taken from each cast, including arch length and width. Dependent t tests were used to evaluate intraexaminer reproducibility and measurement accuracy on the digital models.
  
  
  RESULTS
  No statistically significant differences were found between the measurements made directly on the dental casts and on the digital models.
  
  
  CONCLUSIONS
  Linear measurements on digital models are accurate and reproducible. Digital models obtained with the surface laser scanner are reliable for measurements of arch width and length.
authors.affiliation: Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, Brazil. dra.marines@uol.com.br
authors.forename: Marinês Vieira S
authors.initials: MV
authors.lastname: Sousa
authors.forename: Eliziane Cossetin
authors.initials: EC
authors.lastname: Vasconcelos
authors.forename: Guilherme
authors.initials: G
authors.lastname: Janson
authors.forename: Daniela
authors.initials: D
authors.lastname: Garib
authors.forename: Arnaldo
authors.initials: A
authors.lastname: Pinzan
mesh_terms: D001641:Bicuspid / Q000033:anatomy & histology; D002508:Cephalometry / Q000706:statistics & numerical data; D003481:Cuspid / Q000033:anatomy & histology; D003724:Dental Arch / Q000033:anatomy & histology; D006696:Holography / Q000706:statistics & numerical data; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000706:statistics & numerical data*; D007180:Incisor / Q000033:anatomy & histology; D007834:Lasers; D003765:Models, Dental / Q000706:statistics & numerical data*; D008963:Molar / Q000033:anatomy & histology; D015203:Reproducibility of Results; D012984:Software; D014584:User-Computer Interface