title: An evaluation of the color stability of tooth-colored restorative materials after bleaching using CIELAB color technique.
abstract: OBJECTIVE
  The aim of this laboratory study was to evaluate the effect of three home bleaching agents: Vivastyle Paint On, Vivastyle, and Opalascence PF on the color stability of the microfilled composite Durafill, the nanofilled composite Filtek Z 350, and the glass ionomer cement Fuji II.
  
  
  METHODS
  There were 3 groups in this study (n=40)-Group I: durafill, Group II: Filtek Z 350, and Group III: Fuji II. Each group was further subdivided into 4 subgroups (n=10), Subgroup A: bleaching with Vivastyle Paint On, Subgroup B: bleaching with Vivastyle, Subgroup C: bleaching with Opalascence PF, and Subgroup D: control specimens stored in distilled water. Bleaching was carried out following the manufacturer's instructions for a period of 14 days. At the end of the bleaching regimen, the specimens were tested for color change using the CIELAB technique and a reflectance spectrophotometer.
  
  
  RESULTS
  The data was subjected to statistical analysis. A Kruskal-Wallis variance analysis and Mann Whitney U test were done to determine the significant color change of the restorative materials. All restorative materials demonstrated a significantly higher color change (DeltaE) with Vivastyle (P < 0.0001). The mean color change of GIC (11.4 +/- 0.3) was the highest among the materials followed by Durafill (7.5 +/- 0.1). Filtek z 350 (0.3 +/- 0.1) showed the least color change with all the bleaching agents.
  
  
  CONCLUSIONS
  Glass ionomer cement showed the highest color change followed by the microfilled composite. The nanofilled composite was found to be highly stable in terms of color.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Chennai, India. ymr357@yahoo.com
authors.forename: Y Madhukar
authors.initials: YM
authors.lastname: Rao
authors.forename: V
authors.initials: V
authors.lastname: Srilakshmi
authors.forename: K Karpaga
authors.initials: KK
authors.lastname: Vinayagam
authors.forename: L Lakshmi
authors.initials: LL
authors.lastname: Narayanan