title: Colour and surface analysis of carbamide peroxide bleaching effects on the dental restorative materials in situ.
abstract: OBJECTIVE
  The aim of this in vivo study was to evaluate the effects of a home-bleaching agent on the color and surface properties of four tooth-colored restorative materials.
  
  
  METHODS
  Two composite resins (a nano-hybrid and a packable), a polyacid-modified composite and a conventional glass-ionomer were tested. Specimens were inserted into custom-fabricated trays, and underwent a routine home-bleaching treatment. CIE Lab* color coordinates of the specimens were obtained using a spectrophotometer. Ultra-structural effects were investigated by SEM and ATR-FTIR. The color data were analyzed with ANOVA and Tukey's post hoc analysis.
  
  
  RESULTS
  Significant color changes were found among all the materials after bleaching. However, the color differences decreased and fell into the clinically acceptable range (except for the compomer) after withdrawal of the bleaching treatment. Surface dissolution was detected in the polyacid-modified composite and glass-ionomer cement. ATR-FTIR analyses found chemical composition alterations in the polyacid-modified composite.
  
  
  CONCLUSIONS
  A 15% carbamide peroxide home-bleaching gel did not cause color changes in the composites and glass-ionomer cement. However, significant color and chemical composition alterations were found in the polyacid-modified composite.
authors.affiliation: Wuhan University, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Li
authors.forename: H
authors.initials: H
authors.lastname: Yu
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D000077463:Carbamide Peroxide; D003116:Color; D020770:Compomers; D003188:Composite Resins; D004338:Drug Combinations; D005260:Female; D005899:Glass Ionomer Cements; D006801:Humans; D008297:Male; D008422:Materials Testing; D016877:Oxidants; D010545:Peroxides; D017797:Prosthesis Coloring; D013053:Spectrophotometry; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014073:Tooth Bleaching; D014508:Urea / Q000031:analogs & derivatives*
chemical_list: D020770:Compomers; D003188:Composite Resins; D004338:Drug Combinations; D005899:Glass Ionomer Cements; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea