title: Color stability of provisional prosthodontic materials.
abstract: BACKGROUND
  Discoloration of provisional prosthodontic materials may result in patient dissatisfaction and additional expense for replacement.
  
  
  OBJECTIVE
  The purpose of this study was to determine the color stability of 5 provisional prosthodontic materials before and after immersion in distilled water or coffee for 20 days or exposure to ultraviolet (UV) light for 24 hours.
  
  
  METHODS
  A total of 105 disc-shaped specimens (20+/-0.1 mm by 1+/-0.05 mm) were fabricated with 5 provisional prosthodontic materials: polyethyl methacrylate resins (Trim II), polymethyl methacrylate resins (Duralay; Alike), and bis-acryl methacrylate resin (Luxatemp; Integrity), according to manufacturers' instructions (n=21). Seven specimens of each material were randomly selected and immersed individually in distilled water (60 degrees C) or coffee (37 degrees C) for 20 days or exposed to UV irradiation for 24 hours, respectively. Color was measured as CIE L*a*b* with a colorimeter before and after the immersion or UV exposure. Color change (Delta E) was calculated and data were analyzed with 1-way ANOVA and the Tukey multiple comparisons test (alpha=.05).
  
  
  RESULTS
  For specimens immersed in water, the color change of bis-acryl-methacrylate-based provisional materials (Integrity and Luxatemp) was significantly less than that of 3 methyl/ethyl methacrylate-based provisional materials (Trim II, Alike, and Duralay) (P<.002). After immersion in coffee, the 3 methyl/ethyl methacrylate-based provisional materials exhibited significantly less color change compared to the 2 bis-acryl methacrylate-based provisional materials (P<.0001). After ultraviolet irradiation, 2 bis-acryl methacrylate-based provisional materials showed significantly less color change than any of the 3 methyl/ethyl methacrylate-based provisional materials (P<.0001).
  
  
  CONCLUSIONS
  Luxatemp and Integrity (bis-acryl-methacrylate-based resins) demonstrated acceptable color stability and were the most color-stable provisional prosthodontic materials tested compared to the methyl/ethyl methacrylate-based resins.
authors.affiliation: Faculty of Dentistry, University of Hong Kong, China.
authors.forename: Arthur S K
authors.initials: AS
authors.lastname: Sham
authors.forename: Frederick C S
authors.initials: FC
authors.lastname: Chu
authors.forename: John
authors.initials: J
authors.lastname: Chai
authors.forename: Tak W
authors.initials: TW
authors.lastname: Chow
mesh_terms: D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003069:Coffee / Q000737:chemistry; D003124:Colorimetry / Q000295:instrumentation; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D017266:Dental Prosthesis; D006801:Humans; D007101:Immersion; D008422:Materials Testing; D008768:Methylmethacrylates / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D017797:Prosthesis Coloring; D013997:Time Factors; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: C414370:Alike dental resin; D003069:Coffee; D003764:Dental Materials; D008768:Methylmethacrylates; D011109:Polymethacrylic Acids; C448321:integrity resin; C098586:luxatemp; D014867:Water; C091347:vinyl ethyl methacrylate; D017438:Bisphenol A-Glycidyl Methacrylate; C034578:Duralay; C009931:poly(ethylmethacrylate)