title: Reliability of linear measurements on a virtual bilateral cleft lip and palate model.
abstract: OBJECTIVE
  To assess the reliability and validity of measurements performed on three-dimensional virtual models of neonatal bilateral cleft lip and palate patients, compared with measurements performed on plaster cast models.
  
  
  METHODS
  Ten high-quality plaster cast models of bilateral cleft lip and palate patients were scanned with an LDI-scanner to obtain a three-dimensional virtual model. Linear measurements were performed on the plaster cast models using a digital caliper and also on the three-dimensional virtual model using Viscam RP version 2.1 software. The measurements were performed by two observers on two occasions.
  
  
  RESULTS
  Intraclass correlations ranging from .81 to .96 were found for all measurements except the measurement between the constructed reference point pr and reference point i (intraclass correlation = .40). A post hoc procedure in which top-view screen prints of the three-dimensional virtual model were used to perform the measurement between reference points pr and i demonstrated an intraclass coefficient of .90.
  
  
  CONCLUSIONS
  Three-dimensional virtual models obtained by laser scanning neonatal cast models of bilateral cleft lip and palate patients can be used reliably and validly to perform linear measurements between existing reference points on the surface of the model using Viscam RP version 2.1 software. Measurements between reference points constructed outside the surface of the model cannot be validly performed on the three-dimensional virtual model with the software used in this study. For these measurements, top-view screen prints of the three-dimensional virtual model can be used.
authors.affiliation: Department of Orthodontics, University Medical Centre Groningen, Groningen, the Netherlands. b.c.m.oosterkamp@dmo.umcg.nl
authors.forename: Barbara C M
authors.initials: BC
authors.lastname: Oosterkamp
authors.forename: Wicher J
authors.initials: WJ
authors.lastname: van der Meer
authors.forename: Majelle
authors.initials: M
authors.lastname: Rutenfrans
authors.forename: Pieter U
authors.initials: PU
authors.lastname: Dijkstra
mesh_terms: D002508:Cephalometry; D002971:Cleft Lip / Q000473:pathology*; D002972:Cleft Palate / Q000473:pathology*; D006801:Humans; D007231:Infant, Newborn; D007834:Lasers; D008437:Maxilla / Q000033:anatomy & histology*; D008953:Models, Anatomic; D015588:Observer Variation; D015203:Reproducibility of Results; D012984:Software; D014584:User-Computer Interface