title: Colour stability, staining and roughness of silorane after prolonged chemical challenges.
abstract: OBJECTIVE
  To investigate the effect of prolonged chemical challenges on colour stability, staining susceptibility, and roughness of a silorane composite material when compared to methacrylate-based composites.
  
  
  METHODS
  Initial colour and roughness were registered for specimens fabricated from methacrylate or silorane composites. Specimens were individually stored at 37°C in 0.02 N citric acid, 0.02 N phosphoric acid, 75% ethanol or distilled water for 7, 14, 21 and 180 days, when new measurements were performed. A staining test was performed after the chemical challenge by immersion in coffee during 3 weeks at 37°C. Colour changes were characterized using the CIEL a b colour system. Data were submitted to analysis of variance for repeated measures, two-way analysis of variance and Tukey's multiple comparison test (α=0.05).
  
  
  RESULTS
  Colour changes on the methacrylate-based resins were considered acceptable (although significantly different) after immersion in water, citric acid, phosphoric acid or ethanol, but were unacceptable for the silorane composite immersed in ethanol for 180 days. The methacrylate-based resins stored in ethanol were significantly more stained by coffee than those stored in other media. The silorane composite demonstrated no staining, but increased roughness, when compared to the methacrylate-based resins.
  
  
  CONCLUSIONS
  No effect of the immersion solution was noticed on roughness of the investigated materials. Ethanol influenced colour stability and staining susceptibility differently for the methacrylate-based and silorane composites.
  
  
  CONCLUSIONS
  The knowledge of how acids and solvents affect the properties of tooth-coloured restorative materials is one of the decision-making criteria for the selection of a restorative material.
authors.affiliation: School of Dentistry, University of Copenhagen, Nørre Allé 20, 2200 Copenhagen N, Denmark. Electronic address: arbe@sund.ku.dk.
authors.forename: Ana Raquel
authors.initials: AR
authors.lastname: Benetti
authors.forename: Vivian Cristiane Bueno
authors.initials: VC
authors.lastname: Ribeiro de Jesus
authors.forename: Natan Luiz
authors.initials: NL
authors.lastname: Martinelli
authors.forename: Renata Corrêa
authors.initials: RC
authors.lastname: Pascotto
authors.forename: Regina Célia
authors.initials: RC
authors.lastname: Poli-Frederico
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D019343:Citric Acid / Q000737:chemistry; D003069:Coffee / Q000737:chemistry; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry; D006801:Humans; D007101:Immersion; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D062047:Silorane Resins / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D003069:Coffee; D003188:Composite Resins; D008689:Methacrylates; D010756:Phosphoric Acids; D011140:Polyurethanes; D062047:Silorane Resins; D012997:Solvents; C544925:filtek P90; C533204:filtek Z350; D014867:Water; C029824:urethane dimethacrylate luting resin; D019343:Citric Acid; D000431:Ethanol; D017438:Bisphenol A-Glycidyl Methacrylate; C030242:phosphoric acid
keywords: Colour; Composite resins; Discolouration; Roughness