title: Color stability of dental composites as a function of shade.
abstract: BACKGROUND
  The selection of shade of composites for restorative applications may have a significant effect on color degradation through environmental exposure.
  
  
  OBJECTIVE
  This study characterized the color changes in composites as a function of shade through environmental effects such as ultraviolet light exposure.
  
  
  METHODS
  Five shades of two composites were subjected to ultraviolet light exposure at 37 degrees C for 24 hours after initial storage for 24 hours in distilled water at 37 degrees C. The lightness and chromaticity values of color were measured both before and after ultraviolet light exposure with a Minolta Chromameter. The total color change as well as changes in the lightness and chromaticity values were measured in the CIE L*a*b* scale and analyzed to monitor color degradation, if any.
  
  
  RESULTS
  Color degradation was a significant function of shade and occurred primarily as an increase in yellowness. Color changes increased with the lightness of the shade in both composite systems.
  
  
  CONCLUSIONS
  The lighter shades of composites were likely to be subject to higher color degradation through environmental effects of ultraviolet light exposure.
authors.affiliation: New Jersey Dental School, New Jersey's University of Health Sciences, Newark 07103, USA.
authors.forename: H
authors.initials: H
authors.lastname: Uchida
authors.forename: J
authors.initials: J
authors.lastname: Vaidyanathan
authors.forename: T
authors.initials: T
authors.lastname: Viswanadhan
authors.forename: T K
authors.initials: TK
authors.lastname: Vaidyanathan
mesh_terms: D000704:Analysis of Variance; D017609:Barium Compounds / Q000737:chemistry / Q000528:radiation effects; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry / Q000528:radiation effects; D003116:Color; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D003793:Dental Restoration, Permanent; D004781:Environmental Exposure; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry / Q000528:radiation effects; D011076:Polycarboxylate Cement / Q000737:chemistry / Q000528:radiation effects; D011092:Polyethylene Glycols / Q000737:chemistry / Q000528:radiation effects; D011109:Polymethacrylic Acids / Q000737:chemistry / Q000528:radiation effects; D011140:Polyurethanes / Q000737:chemistry / Q000528:radiation effects; D011829:Radiation Dosage; D012822:Silicon Dioxide / Q000737:chemistry / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D017609:Barium Compounds; D003188:Composite Resins; C092421:Conquest composite resin; D003764:Dental Materials; D008689:Methacrylates; D011076:Polycarboxylate Cement; D011109:Polymethacrylic Acids; D011140:Polyurethanes; C102738:barium glass filler; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; C005506:polycarbonate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide