title: Composite resin color stability: influence of light sources and immersion media.
abstract: OBJECTIVE
  This study evaluated the influence of light sources and immersion media on the color stability of a nanofilled composite resin.
  
  
  METHODS
  Conventional halogen, high-power-density halogen and high-power-density light-emitting diode (LED) units were used. There were 4 immersion media: coffee, tea, Coke® and artificial saliva. A total of 180 specimens (10 mm x 2 mm) were prepared, immersed in artificial saliva for 24 h at 37±1ºC, and had their initial color measured with a spectrophotometer according to the CIELab system. Then, the specimens were immersed in the 4 media during 60 days. Data from the color change and luminosity were collected and subjected to statistical analysis by the Kruskall-Wallis test (p<0.05). For immersion time, the data were subjected to two-way ANOVA test and Fisher's test (p<0.05).
  
  
  RESULTS
  High-power-density LED (ΔE=1.91) promoted similar color stability of the composite resin to that of the tested halogen curing units (Jet Lite 4000 plus--ΔE=2.05; XL 3000--ΔE=2.28). Coffee (ΔE=8.40; ΔL=-5.21) showed the highest influence on color stability of the studied composite resin.
  
  
  CONCLUSIONS
  There was no significant difference in color stability regardless of the light sources, and coffee was the immersion medium that promoted the highest color changes on the tested composite resin.
authors.affiliation: Department of Dentistry, University Center of Araraquara, Araraquara, SP, Brazil. psgarcia@foar.unesp.br
authors.forename: Patricia Aleixo dos Santos
authors.initials: PA
authors.lastname: Domingos
authors.forename: Patrícia Petromilli Nordi Sasso
authors.initials: PP
authors.lastname: Garcia
authors.forename: Ana Luisa Botta Martins de
authors.initials: AL
authors.lastname: Oliveira
authors.forename: Regina Guenka
authors.initials: RG
authors.lastname: Palma-Dibb
mesh_terms: D000704:Analysis of Variance; D001628:Beverages; D003116:Color; D003124:Colorimetry; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D055117:Curing Lights, Dental; D007101:Immersion; D008422:Materials Testing; D012464:Saliva, Artificial / Q000737:chemistry; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003188:Composite Resins; C474035:Filtek Supreme; D012464:Saliva, Artificial