Effect of Antimicrobial Filler on Ethylene-Vinyl Acetate (EVA) Composites Property

Ethylene-vinyl acetate (EVA) is a versatile polymer for applications in dental devices; however, its vulnerability to microbial colonization increases with long-term use. This study evaluates EVA composites modified with silver-sodium-hydrogen-zirconium phosphate (SP) particles, aimed at enhancing antimicrobial performance while preserving key functional properties. Composites containing 1-16 wt.% SP were prepared via solvent-based and mechanical compounding routes, with scanning electron microscopy confirming correct filler distribution across processing methods. Antimicrobial assays revealed a pronounced reduction in Streptococcus mutans and Candida albicans levels, reaching 88% and 98% antimicrobial efficacy, respectively, at 16 wt.% SP. Cytotoxicity testing with L-929 fibroblasts demonstrated maintained cell viability above the 70% threshold, confirming non-cytotoxicity. Mechanical characterization indicated marginal increases in hardness, slight tensile strength reduction at higher filler loadings, while other physicochemical and thermal analyses showed minimal impact on polymer performance. These findings indicate balanced antimicrobial activity with other biofunctional properties.