Color Stability and Surface Properties of PMMA/ZrO(2) Nanocomposite Denture Base Material after Using Denture Cleanser

OBJECTIVES: This study aimed to evaluate denture cleanser effects on color stability, surface roughness, and hardness of PMMA denture base resin reinforced with nano-ZrO(2). MATERIALS AND METHODS: A total of 420 specimens were fabricated of unreinforced and nano-ZrO(2) reinforced acrylic resin at 2.5% and 5%, resulting in 3 main groups. These groups were further subdivided (n = 10) according to immersion solution (distilled water, Corega, sodium hypochlorite, and Renew) and immersion duration. Surface roughness, hardness, and color were measured at baseline (2 days-T(0)) in distilled water and then after 180 and 365 days of immersion (T(1) & T(2)) in water or denture cleansing solutions. Data was collected and analyzed using two-way ANOVA followed by Bonferroni post hoc test (α = 0.05). RESULTS: Surface roughness increased significantly after denture cleanser immersion of unmodified and nano-ZrO(2)-modified PMMA materials while hardness decreased (P < 0.001). The denture cleansers significantly affected the color of both PMMA denture bases (P < 0.001). The immersion time in denture cleansers significantly affected all tested properties (P < 0.001). Within denture cleansers, NaOCl showed the highest adverse effects (P < 0.05) while Renew showed the least adverse effects. CONCLUSION: Denture cleansers can significantly result in color change and alter the surface roughness and hardness of denture base resin even with ZrO(2) nanoparticles addition. Therefore, they should be carefully used.