title: Color stability of silorane-based composites submitted to accelerated artificial ageing--an in situ study.
abstract: OBJECTIVE
  To assess the in situ color stability, surface and the tooth/restoration interface degradation of a silorane-based composite (P90, 3M ESPE) after accelerated artificial ageing (AAA), in comparison with other dimethacrylate monomer-based composites (Z250/Z350, 3M ESPE and Esthet-X, Dentsply).
  
  
  METHODS
  Class V cavities (25 mm(2) × 2 mm deep) were prepared in 48 bovine incisors, which were randomly allocated into 4 groups of 12 specimens each, according to the type of restorative material used. After polishing, 10 specimens were submitted to initial color readings (Easyshade, Vita) and 2 to analysis by scanning electronic microscopy (SEM). Afterwards, the teeth were submitted to AAA for 384 h, which corresponds to 1 year of clinical use, after which new color readings and microscopic images were obtained. The values obtained for the color analysis were submitted to statistical analysis (1-way ANOVA, Tukey, p<0.05).
  
  
  RESULTS
  With regard to color stability, it was verified that all the composites showed color alteration above the clinically acceptable levels (ΔE ≥ 3.3), and that the silorane-based composite showed higher ΔE (18.6), with a statistically significant difference in comparison with the other composites (p<0.05). The SEM images showed small alterations for the dimethacrylate-based composites after AAA and extensive degradation for the silorane-based composite with a rupture at the interface between the matrix/particle.
  
  
  CONCLUSIONS
  It may be concluded that the silorane-based composite underwent greater alteration with regard to color stability and greater surface and tooth/restoration interface degradation after AAA.
authors.affiliation: Department of Dental Materials and Prosthodontics, Ribeirão Preto School of Dentistry, University of São Paulo, Ribeirão Preto, SP, Brazil. ferpanzeri@forp.usp.br
authors.forename: Fernanda de Carvalho Panzeri
authors.initials: Fde C
authors.lastname: Pires-de-Souza
authors.forename: Lucas da Fonseca Roberti
authors.initials: Lda F
authors.lastname: Garcia
authors.forename: Lourenço de Moraes Rego
authors.initials: Lde M
authors.lastname: Roselino
authors.forename: Lucas Zago
authors.initials: LZ
authors.lastname: Naves
mesh_terms: D000818:Animals; D002417:Cattle; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D019554:Dental Restoration Wear; D003799:Dental Stress Analysis; D008422:Materials Testing; D011897:Random Allocation; D012833:Siloxanes; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003188:Composite Resins; C466112:Esthet-X; C444701:Filtek Z250; D012833:Siloxanes; C544925:filtek P90