title: Assessment of early attrition using an ordinary flatbed scanner.
abstract: The aim of this study was to assess a two-dimensional method to monitor occlusal tooth wear quantitatively using a commercially available ordinary flatbed scanner.
  
  
  METHODS
  A flatbed scanner, measuring software and gypsum casts were used. In Part I, two observers (A and B) independently traced scans of marked wear facets of ten sets of casts in two sessions (test and retest). In Part II, three other sets of casts were duplicated and two observers (C and D) marked wear facets and traced the scanned images independently. Intra- and inter-observer agreement was determined comparing measured values (mm(2)) in paired T-tests. Duplicate measurement errors (DME) were calculated.
  
  
  RESULTS
  In Part I the test and retest values (10 casts, 218 teeth) of observer A and B did not differ significantly (A: p = 0.289; B: p = 0.666); correlation coefficients were 0.998 (A) and 0.999 (B). "Tracing wear facets" showed a DME of 0.30 mm(2) for observer A and 0.15 mm(2) for observer B. In Part II, assessment of 70 teeth resulted in correlation coefficients of 0.994 for observer C and 0.997 for observer D; no differences between test and retest values were found for C (p = 0.061), although D differed significantly (p = 0.000). The DME for "marking and tracing wear facets" was 0.39 mm(2) (C) and 0.27 mm(2) (D). DME for inter-observer agreement were 0.45 mm(2) (test) and 0.42 mm(2) (re-test).
  
  
  CONCLUSIONS
  We conclude that marking and tracing of occlusal wear facets to assess occlusal tooth wear quantitatively can be done accurately and reproducibly.
authors.affiliation: Department of Oral Function and Prosthetic Dentistry, College of Dental Science, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. a.vantspijker@dent.umcn.nl
authors.forename: Arie
authors.initials: A
authors.lastname: Van't Spijker
authors.forename: Cees M
authors.initials: CM
authors.lastname: Kreulen
authors.forename: Ewald M
authors.initials: EM
authors.lastname: Bronkhorst
authors.forename: Nico H J
authors.initials: NH
authors.lastname: Creugers
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D003765:Models, Dental; D015588:Observer Variation; D012984:Software; D019217:Tooth Attrition / Q000175:diagnosis* / Q000473:pathology; D057085:Tooth Wear / Q000175:diagnosis / Q000473:pathology