title: Minimum color differences for discriminating mismatch between composite and tooth color.
abstract: OBJECTIVE
  The purpose of this study was to determine if there are differences between patients and dental professionals in their ability to identify small color differences (deltaE) in composite resin restorative materials in vitro and to determine the deltaE that would indicate acceptability of color match between a restoration and an adjacent tooth.
  
  
  METHODS
  Subjects were asked to evaluate composite resin disks to distinguish acceptability of deltaE between disk pairs. Color difference discrimination of dental professionals groups D1 (dentists, n = 12) and D2 (dental auxiliaries, n = 12) was compared to that of dental patient groups P1 (patients, n = 12) and P2 (scientists, n = 12). Each group was pretested for normal color vision. Color differences between a standard and restoration disks of composite were measured in Colour Measurement Committee (CMC) (1:1) color units. Data were analyzed by logistic regression, and results were used to calculate a probability level for minimal acceptance or rejection of AE for all observers. Mean 50:50 deltaE replacement points (RP) for each group were obtained and analyzed by analysis of variance, and the Tukey pairwise comparison test was applied (alpha = 0.05 for all statistical analyses).
  
  
  RESULTS
  There were significant differences found between the experimental groups (p = .020). Group D2 (mean 50:50 deltaE RP = 1.78) proved to be more discriminating in accepting differences between tooth and composite resin restorative material color than group P1 (mean 50:50 deltaE RP = 2.69). The mean 50:50 deltaE RP for all subjects was 2.29 CMC (1:1) units.
  
  
  CONCLUSIONS
  The ability to generate an excellent color match between a tooth-colored restoration and the tooth is critical to esthetic success. This study demonstrates that patients are not as discriminating in their ability to identify small color differences between composite restorations and the tooth as are dental professionals. Dental auxiliaries proved to be more discriminating in accepting differences between tooth and composite resin restorative material color than were patients.
authors.affiliation: The Naval Dental Research Institute, Great Lakes, Illinois 60088-525, USA. james.ragain@ndri.med.navy.mil
authors.forename: J C
authors.initials: JC
authors.lastname: Ragain
authors.forename: W M
authors.initials: WM
authors.lastname: Johnston
mesh_terms: D000704:Analysis of Variance; D003116:Color; D003118:Color Perception; D003188:Composite Resins / Q000737:chemistry*; D003727:Dental Auxiliaries; D003815:Dentists; D006801:Humans; D016015:Logistic Models; D010361:Patients; D011336:Probability; D019279:Resin Cements / Q000737:chemistry; D012586:Science; D013056:Spectrophotometry, Ultraviolet; D013223:Statistics as Topic; D014070:Tooth / Q000033:anatomy & histology*
chemical_list: D003188:Composite Resins; D019279:Resin Cements; C420128:Spectrum composite resin; C113300:TPH hybrid; C065770:Herculite XR