title: The reproducibility of landmarks on three-dimensional images of 4- to 6-year-old children.
abstract: OBJECTIVE
  The objective of this study was to check the reproducibility and influencing parameters of landmarks on three-dimensional images of 4- to 6-year-old Caucasian children.
  
  
  METHODS
  We examined the reproducibility of 22 landmarks on six three-dimensional facial scans of 4- to 6-year-old randomly-selected kindergarten children. The 3D scans were taken by the digital system faceSCAN II under standardized conditions. One specially-trained investigator marked all landmarks on each of the six 3D scans a total of ten times. Ten different orthodontic residents also placed all landmarks on each of these scans. Standard deviations from the mean were then calculated from the data for each individual landmark on the x-, y- and z-axes.
  
  
  RESULTS
  The specially-trained investigator who had placed all landmarks on each of the six 3D scans a total of ten times found 15 of 22 landmarks to be reproducible well to within a standard deviation of less than 1 mm on each spatial plane. For the ten orthodontic residents, only three landmarks were found to be reproducible to within a standard deviation of under 1 mm for each spatial plane.
  
  
  CONCLUSIONS
  Familiarity with 3D facial scans and their corresponding software programs, together with good image quality, improve the reproducibility of the analysis. Landmarks revealing poor reproducibility should be used, if at all, with due caution for analysis. It remains to be seen whether they can be omitted altogether, or whether they should be re-set.
authors.affiliation: Department of Orthodontics, Eberhard Karl University, Tübingen, Germany. mirjamhoenn@web.de
authors.forename: Mirjam
authors.initials: M
authors.lastname: Berneburg
authors.forename: Carolin
authors.initials: C
authors.lastname: Schubert
authors.forename: Claudia
authors.initials: C
authors.lastname: von Einem
authors.forename: Edgar
authors.initials: E
authors.lastname: Schaupp
authors.forename: Mathias
authors.initials: M
authors.lastname: Möller
authors.forename: Gernot
authors.initials: G
authors.lastname: Göz
mesh_terms: D000465:Algorithms; D002648:Child; D002675:Child, Preschool; D005145:Face / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D015588:Observer Variation; D023861:Photography, Dental / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity