Dispersibility of SZP Antimicrobial Agents in Silicone Denture Soft Lining Materials and Their Effect on Operational Performance

The purpose of this study is to investigate the dispersibility of silver-zirconium phosphate (SZP) nano-inorganic antimicrobial agent in silicone denture soft lining materials and the effect of adding the agent on operational performances. SZP was added using the method of high shear emulsification dispersion. The mass percent of antimicrobial agent was 2%, 5%, and 10%. Silicone soft lining materials without antimicrobial agent served as controls. Dispersibility of SZP in silicone soft lining materials was observed under scanning electron microscope (SEM), and the attribution of the elements on the cross section was analyzed by energy dispersive analysis system (EDS). Operational properties of materials with and without SZP were tested to find out the effect of adding SZP on these properties, including mixing time, consistency, working time and setting time. By SEM observation, inorganic nano-granules were well-distributed in silicone substrate. Element analysis showed even distribution of Zr and Ag, which confirmed there were not obvious nano-agglomerates, and in turn verified the excellent dispersibility of SZP in tested silicone materials. EDS spectra showed that the mass proportion of Zr in samples containing 5% SZP was low, suggesting the main content was still silicon compound. Adding SZP by the proportions mentioned above prolonged mixing time of the material, i.e. the easy-mixed capability of the material was decreased. But consistency, working time and setting time of the material were not significantly affected. The method of high shear emulsification dispersion is capable to make SZP nano-inorganic antimicrobial agent distribute evenly in silicone soft lining substrate, without obvious agglomeration. Adding SZP will not significantly affect operational properties of silicone denture soft lining material.