title: Color stability of provisional restorative materials after accelerated aging.
abstract: OBJECTIVE
  Color of 11 provisional restorative materials (4 acrylic resins and 7 resin composites) was evaluated by reflection spectrophotometry immediately after fabrication, after aging for 15 kJ/m(2), and after aging for 60 kJ/m(2) to determine relative color stability under experimental aging conditions.
  
  
  METHODS
  Specimens of provisional restorative materials were polymerized according to manufacturers' instructions and aged in an artificial aging chamber with exposure to a total ultraviolet irradiation of 60 kJ/m(2) in increments of 15 kJ/m(2). Color was measured by CIE L*a*b* on a reflection spectrophotometer before and after aging. Color change (Delta E*) was calculated and analyzed statistically by analysis of variance with repeated measures after 15 and 60 kJ/m(2) intervals of aging.
  
  
  RESULTS
  Statistically significant changes in color were observed after accelerated aging at both the initial and final aging intervals. Five of the 11 provisional materials tested showed perceptible color change (Delta E* from 3.6 to 9.3) after accelerated aging of 15 kJ/m(2). Seven of the 11 provisional materials tested showed perceptible color change (Delta E* from 3.4 to 9.4) after accelerated aging of 60 kJ/m(2).
  
  
  CONCLUSIONS
  Clinically perceptible color changes (Delta E* Delta 3.3) can be expected in some acrylic resin and composite resin provisional materials after accelerated aging.
authors.affiliation: Department of Restorative Dentistry, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, USA.
authors.forename: P G
authors.initials: PG
authors.lastname: Doray
authors.forename: D
authors.initials: D
authors.lastname: Li
authors.forename: J M
authors.initials: JM
authors.lastname: Powers
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry* / Q000528:radiation effects; D000704:Analysis of Variance; 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; D003794:Dental Restoration, Temporary; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry / Q000528:radiation effects; D019904:Polymethyl Methacrylate / Q000737:chemistry / Q000528:radiation effects; D011829:Radiation Dosage; D013053:Spectrophotometry; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D000180:Acrylic Resins; D003188:Composite Resins; D003764:Dental Materials; D008689:Methacrylates; C106970:Provipont system; D017438:Bisphenol A-Glycidyl Methacrylate; D019904:Polymethyl Methacrylate; C069714:Protemp; C016284:butyl methacrylate