In Vitro Assessment of Artificial Aging on the Antifungal Activity of PMMA Denture Base Material Modified with ZrO₂Nanoparticles

The antifungal effect of zirconium dioxide nanoparticles (ZrO2NPs) incorporated into denture base material has been inadequately investigated; additionally, to the authors' knowledge, no studies have assessed the influence of artificial aging on the antifungal activity of these particles. Methodology. Heat-polymerized acrylic resin disks were fabricated and divided into four groups (0%, 1%, 2.5%, and 5% ZrO2NPs by weight). Antifungal activity was assessed using the direct culture and disk diffusion methods. Surface roughness and contact angles were measured using a profilometer and a goniometer, respectively. The artificial aging procedure was performed by repeating all tests at 7, 14, and 30 days following 2 rounds of thermocycling. Data were analyzed using ANOVA and Tukey's post-hoc test (p<0.05). Results. The addition of ZrO2NPs significantly decreased the adhesion of Candida albicans with and without artificial aging procedures (p<0.001), while the disk diffusion methods did not reveal inhibition zones. ZrO2NP-modified specimens displayed significantly higher surface roughness compared to specimens in the control group (p<0.05) and showed the same behaviors with artificial aging procedures. The contact angle was significantly decreased in all modified groups in comparison to the control group (p<0.05). Conclusion. The addition of ZrO2NPs to polymethylmethacrylate denture base material reduced the adhesion of Candida albicans with a long-term antifungal effect. With the addition of ZrO2NPs, contact angles were decreased and surface roughness was increased; 1% was the most appropriate concentration. Clinical significance. The addition of ZrO2NPs to denture base material confers a long-term antifungal effect and could be used as a possible method for preventing and treating denture stomatitis.