title: The in vitro and in vivo validation of a mobile non-contact camera-based digital imaging system for tooth colour measurement.
abstract: OBJECTIVE
  To assess the reproducibility of a mobile non-contact camera-based digital imaging system (DIS) for measuring tooth colour under in vitro and in vivo conditions.
  
  
  METHODS
  One in vitro and two in vivo studies were performed using a mobile non-contact camera-based digital imaging system. In vitro study: two operators used the DIS to image 10 dry tooth specimens in a randomised order on three occasions. In vivo study 1:25 subjects with two natural, normally aligned, upper central incisors had their teeth imaged using the DIS on four consecutive days by one operator to measure day-to-day variability. On one of the four test days, duplicate images were collected by three different operators to measure inter- and intra-operator variability. In vivo study 2:11 subjects with two natural, normally aligned, upper central incisors had their teeth imaged using the DIS twice daily over three days within the same week to assess day-to-day variability. Three operators collected images from subjects in a randomised order to measure inter- and intra-operator variability.
  
  
  RESULTS
  Subject-to-subject variability was the largest source of variation within the data. Pairwise correlations and concordance coefficients were > 0.7 for each operator, demonstrating good precision and excellent operator agreement in each of the studies. Intraclass correlation coefficients (ICCs) for each operator indicate that day-to-day reliability was good to excellent, where all ICC's where > 0.75 for each operator.
  
  
  CONCLUSIONS
  The mobile non-contact camera-based digital imaging system was shown to be a reproducible means of measuring tooth colour in both in vitro and in vivo experiments.
authors.affiliation: International Collaborating Centre in Oro-facial Genetics and Development, Liverpool University Dental Hospital & School of Dentistry, Edwards Building, Daulby Street, Liverpool L69 3GN, UK.
authors.forename: Richard N
authors.initials: RN
authors.lastname: Smith
authors.forename: Luisa Z
authors.initials: LZ
authors.lastname: Collins
authors.forename: Mojgan
authors.initials: M
authors.lastname: Naeeni
authors.forename: Andrew
authors.initials: A
authors.lastname: Joiner
authors.forename: Carole J
authors.initials: CJ
authors.lastname: Philpotts
authors.forename: Ian
authors.initials: I
authors.lastname: Hopkinson
authors.forename: Clare
authors.initials: C
authors.lastname: Jones
authors.forename: Darren L
authors.initials: DL
authors.lastname: Lath
authors.forename: Thomas
authors.initials: T
authors.lastname: Coxon
authors.forename: James
authors.initials: J
authors.lastname: Hibbard
authors.forename: Alan H
authors.initials: AH
authors.lastname: Brook
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003116:Color; D003124:Colorimetry / Q000295:instrumentation; D003481:Cuspid / Q000033:anatomy & histology; D004867:Equipment Design; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D007180:Incisor / Q000033:anatomy & histology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D023861:Photography, Dental / Q000295:instrumentation*; D015203:Reproducibility of Results; D013997:Time Factors; D014070:Tooth / Q000033:anatomy & histology*