title: Colour-stability and gloss-retention of silorane and dimethacrylate composites with accelerated aging.
abstract: OBJECTIVE
  To evaluate the colour-stability and gloss-retention of silorane versus dimethacrylate composites exposed to accelerated aging from daylight radiation.
  
  
  METHODS
  Five disc-shaped specimens of photo-cured resin-composites were prepared and manually polished for each material (Filtek Silorane, Herculite XRV, Tetric Evoceram and QuiXfil). Colour and gloss were evaluated before and after periods (baseline, 24, 72, 120 and 192 h) of accelerated photo-aging in xenon light following ISO 7491:2000. Colour measurements were performed with a colourimeter according to the CIE-Lab colour-space. The colour change (DeltaE) for each time was calculated. The surface gloss was measured using a glossmeter. Results were evaluated using one-way ANOVA and Tukey tests (alpha=0.05). Correlations between logtime, DeltaE and gloss were evaluated using Pearson's correlation (alpha=0.05).
  
  
  RESULTS
  Materials generally decreased in L and a and increased in b. The strong exception was Filtek Silorane which maintained a and b. DeltaE was found to be a positive linear function of logtime for all materials. Materials varied in the magnitude and rate of increase of DeltaE with logtime: QuiXfil>Tetric EvoCeram>(Filtek Silorane>or=Herculite XRV). DeltaE remained<3.3 for Filtek Silorane and Herculite XRV. Gloss was found to be a negative linear function of logtime. Gloss was maximal in the sequence: Filtek Silorane approximately Tetric EvoCeram>Herculite XRV>QuiXfil.
  
  
  CONCLUSIONS
  Silorane gave the best overall performance in stability over time, compared to a set of representative dimethacrylate composites.
authors.affiliation: Biomaterials Science Research Group, School of Dentistry, The University of Manchester, Manchester, United Kingdom. furuseay@yahoo.com.br
authors.forename: Adilson Y
authors.initials: AY
authors.lastname: Furuse
authors.forename: Kathryn
authors.initials: K
authors.lastname: Gordon
authors.forename: Flávia P
authors.initials: FP
authors.lastname: Rodrigues
authors.forename: Nick
authors.initials: N
authors.lastname: Silikas
authors.forename: David C
authors.initials: DC
authors.lastname: Watts
mesh_terms: D000704:Analysis of Variance; D003124:Colorimetry; D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects*; D017220:Dentin-Bonding Agents / Q000737:chemistry / Q000528:radiation effects*; D008027:Light; D008689:Methacrylates / Q000737:chemistry / Q000528:radiation effects*; D017797:Prosthesis Coloring; D019279:Resin Cements / Q000737:chemistry / Q000528:radiation effects*; D062047:Silorane Resins; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; D008689:Methacrylates; C510379:QuiXfil; D019279:Resin Cements; D062047:Silorane Resins; C501891:Tetric EvoCeram; C065770:Herculite XR