Antifungal activity and effects on denture base resin properties of effervescent cleansing granules containing silanized zinc oxide nanoparticles and sodium lauryl sulfate

Effervescent denture cleansers are widely used to reduce microbial contamination on dentures but may have limited antifungal efficacy and adversely affect denture base properties. This study evaluated antifungal activity of effervescent cleansing granules containing silanized zinc oxide nanoparticles (SiZnOnps) and sodium lauryl sulfate (SLS) against Candida albicans , and their effects on color change, microhardness, and surface roughness of denture base resin. A total of 135 disk-shaped specimens were fabricated using heat-activated polymethylmethacrylate resin and divided into 9 cleansing groups: effervescent cleansing granules containing SiZnOnps (0.6Zn, 1.2Zn, 2.5Zn, 0.6ZnSLS, 1.2ZnSLS, and 2.5ZnSLS), effervescent cleansing granules without SiZnOnps or SLS (EF), commercial effervescent cleansing tablet (PO), and deionized water (DI; control). Specimens were immersed in the corresponding cleansing groups, and antifungal activity against Candida albicans was evaluated by determining residual Candida albicans colony counts (log CFU/mL) ( n = 5). Color change (ΔE), microhardness (VHN), and surface roughness (R a ) were evaluated at baseline and after 7, 30, and 90 days of immersion ( n = 10). One-way ANOVA was used to analyze antifungal activity, whereas 2-way repeated measures ANOVA was used to analyze ΔE, VHN, and R a values (α = 0.05). Compared with the DI group, the 0.6Zn and EF groups showed no significant differences in log CFU/mL values ( P > 0.05), whereas all other groups showed significantly lower values ( P < 0.05). The 1.2ZnSLS and PO groups did not differ significantly ( P > 0.05) and exhibited no detectable fungal growth. At the same SiZnOnp concentration, the SLS groups exhibited significantly lower log CFU/mL values than the corresponding non-SLS groups ( P < 0.05). Most cleansing groups exhibited ΔE, VHN, and R a values comparable to those of the DI group at each immersion time ( P > 0.05). After 90-day immersion, most cleansing groups maintained comparable ΔE values over time ( P > 0.05), whereas R a values decreased ( P < 0.05). VHN remained unchanged in the 0.6Zn, 2.5Zn, 0.6ZnSLS, 1.2ZnSLS, and 2.5ZnSLS groups, decreased in the 1.2Zn group, and increased in the PO, EF, and DI groups ( P < 0.05). Effervescent cleansing granules containing 1.2ZnSLS demonstrated antifungal activity against Candida albicans comparable to that of commercial effervescent tablet after 60-minutes immersion, without adversely affecting color change, microhardness, or surface roughness of denture base resin after 90-day immersion.