title: Color and structural changes of a maxillofacial elastomer: the effects of accelerated photoaging, disinfection and type of pigments.
abstract: OBJECTIVE
  The aim of this study was to investigate the color and structural changes of a maxillofacial silicone colored with 2 different pigments, after photoaging and immersion in disinfectants.
  
  
  METHODS
  Ninety-six cylindrical specimens were fabricated and divided into 3 equal groups. The specimens of the first group consisted of unpigmented silicone (Multisil Epithetik), those of the second group consisted of unpigmented silicone, colored with red functional liquid pigment (Cosmesil Reactive 0.2% wt). The specimens of the third group were fabricated using unpigmented silicone colored with red powder pigment Cosmesil Dry at 0.2% wt. Specimens of each group were divided into 4 equal subgroups (immersed in soap solution, ethanol 95° or distilled water or placed in a photoaging apparatus for 174 hours). Structural changes were examined by infrared spectroscopy (ATR-FTIR) before and after aging. Color changes (ΔΕ*) were measured using the CIE L*a*b* system. Two-way ANOVA and Tukey's test for post hoc comparison were used at a = 0.05.
  
  
  RESULTS
  Infrared spectroscopy showed no structural changes after immersion in solutions and photoaging, for all the materials tested. No statistically significant differences for ΔΕ* among the tested groups were found.
  
  
  CONCLUSIONS
  It can be concluded that no structural changes of pigmented and unpigmented silicone elastomers were observed among all aging procedures. Recorded color changes for the materials tested were within the limits of clinical acceptability after all aging procedures. Immersion in distilled water presented the best color stability, whereas photoaging, the poorest, for all materials.
authors.affiliation: Department of Biomaterials, Dental School, University of Athens, Athens - Greece.
authors.forename: Panagiota
authors.initials: P
authors.lastname: Griniari
authors.affiliation: Department of Prosthodontics, Dental School, University of Athens, Athens - Greece.
authors.forename: Gregory
authors.initials: G
authors.lastname: Polyzois
authors.affiliation: Department of Biomaterials, Dental School, University of Athens, Athens - Greece.
authors.forename: Triantafillos
authors.initials: T
authors.lastname: Papadopoulos
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D003116:Color; D004202:Disinfectants / Q000737:chemistry; D020724:Elastomers / Q000737:chemistry* / Q000528:radiation effects*; D008422:Materials Testing; D008447:Maxillofacial Prosthesis; D055668:Photochemical Processes; D013472:Sunlight; D013997:Time Factors
chemical_list: D001672:Biocompatible Materials; D004202:Disinfectants; D020724:Elastomers