The Impact of Zinc Oxide Nanoparticles on the Color Stability and Surface Roughness of Heat-Polymerized Maxillofacial Silicone Elastomer Subjected to Artificial Aging: An In Vitro Study

In this study, zinc oxide nanoparticles are utilized to assess the color stability and surface roughness of heat-temperature vulcanized maxillofacial silicone under simulated aging conditions. Silicone specimens were created with different concentrations of ZnO nanoparticles (0 wt%, 1 wt%, 2 wt%, 3 wt%, and 4 wt%) and pigmented with two inherent colors (soft brown and rose silk). The color stability was evaluated by calculating the CIELAB color space, and the surface roughness was analyzed both before and after UV exposure. The applied method considerably improved color stability, with the best results achieved when 1 wt% and 3 wt% ZnO were used. During the aging periods, the soft brown pigment was more resistant to discoloration than rose silk. The incorporation of ZnO resulted in a reduction in the initial surface roughness parameters, while simultaneously increasing the surface's resistance to UV-induced degradation. Substantial increases in roughness were observed in the control samples. By contrast, adding ZnO improved surface integrity. In conclusion, including an optimized amount of ZnO nanoparticles to heat-polymerized maxillofacial silicone can increase the lifespan of silicone prostheses, providing a smooth appearance and resistance to environmental factors.