Effects of the addition of titanium dioxide and silaned silica nanoparticles on the color stability of a maxillofacial silicone elastomer submitted to artificial aging

Abstract

Silicone elastomers require replacement due to degradation of mechanical properties and deterioration in color over time. Recently, various nanoparticles have been incorporated into the silicones to reinforce their physical and mechanical properties. The purpose of this study was to evaluate the effect of nanosized particle addition on the color stability of a commercial RTV maxillofacial silicone elastomer submitted to an accelerated aging. The nanosized particles (titanium dioxide and silaned silica) were added, 10% by volume, into a maxillofacial elastomer. The samples (n=10) were polymerized in an oven according to the manufacturer’s recommendations. Color measurements were performed using digital spectrophotometry according to the CIE L*a*b* color system. The samples were subsequently placed into an aging chamber for 168 h. The second color measurement of the samples was performed after the aging process. Data obtained from the measurement was recorded and assessed by (ANOVA) (α=0.05). The highest color stability was obtained with the silica and the TiO 2 group samples; the lowest color stability was obtained with the control group samples in this study. However; no statistically significant difference in discoloration was observed in the ∆E values between the groups (p > 0.05). The results of this pilot study revealed that the addition of nanosized TiO 2 and silica particles used as reinforcing agents did not cause any color degradation of an A-2000 silicone during the first 2 months. Further studies should be done on the effect of such nanoparticles in long term aging procedures on the color stability of maxillofacial elastomers. Key Words: Color stability, nanoparticles, maxillofacial silicones.