title: Influence of pigments and opacifiers on color stability of an artificially aged facial silicone.
abstract: OBJECTIVE
  The aim of this study was to evaluate the influence of two pigments (ceramic powder and oil paint) and one opacifier (barium sulfate) on the color stability of MDX4-4210 facial silicone submitted to accelerated aging.
  
  
  METHODS
  Sixty specimens of silicone were fabricated and divided into six groups--colorless (G1), colorless with opacifier (G2), ceramic (G3), ceramic with opacifier (G4), oil (G5), oil with opacifier (G6). All replicas were submitted to accelerated aging for 1008 hours. The evaluations of chromatic alteration through visual analysis and reflection spectrophotometry were carried out initially and after 252, 504, and 1008 hours of aging. The results were submitted to ANOVA and Tukey's test at 5% level of significance.
  
  
  RESULTS
  All groups exhibited chromatic alteration (ΔE > 0); however, this color alteration was not perceptible through visual analysis of the color. The pigmented groups with opacifier presented the lowest ΔE values, with a statistical difference from the other groups. For the groups without opacifier, the group pigmented with oil paint exhibited the lowest ΔE values in the different aging periods, with a statistical difference. Accelerated aging generated significant chromatic alterations in all groups after 252 hours, except for the colorless and oil groups, both with opacifier (G2 and G6).
  
  
  CONCLUSIONS
  The opacifier protects facial silicones against color degradation, and oil paint is a stable pigment even without addition of opacifier.
authors.affiliation: Department of Dental Materials and Prosthodontics, Araçatuba Dental School, UNESP, Araçatuba, Brazil.
authors.forename: Daniela Micheline
authors.initials: DM
authors.lastname: dos Santos
authors.forename: Marcelo Coelho
authors.initials: MC
authors.lastname: Goiato
authors.forename: Amália
authors.initials: A
authors.lastname: Moreno
authors.forename: Aldiéris Alves
authors.initials: AA
authors.lastname: Pesqueira
authors.forename: Marcela Filiè
authors.initials: MF
authors.lastname: Haddad
mesh_terms: D001466:Barium Sulfate / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry* / Q000528:radiation effects; D002516:Ceramics / Q000737:chemistry; D003116:Color; D004396:Coloring Agents / Q000737:chemistry*; D004129:Dimethylpolysiloxanes / Q000737:chemistry* / Q000528:radiation effects; D006801:Humans; D008422:Materials Testing; D008447:Maxillofacial Prosthesis; D010150:Paint; D017797:Prosthesis Coloring; D012826:Silicone Elastomers / Q000737:chemistry* / Q000528:radiation effects; D013056:Spectrophotometry, Ultraviolet; D013472:Sunlight; D013499:Surface Properties; D013997:Time Factors; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D004396:Coloring Agents; D004129:Dimethylpolysiloxanes; C020964:MDX 4-4210; D012826:Silicone Elastomers; D014867:Water; D001466:Barium Sulfate