Nanocomposites soft and hard denture liners containing ZrO₂ nanoparticles: An in vitro evaluation of surface roughness and Candida albicans adhesion

Purpose: To investigate the impact of zirconium dioxide nanoparticles (nano-ZrO₂) addition to hard and soft liners on the surface roughness and Candida albicans adhesion. Materials and Methods: Nano-ZrO₂ was added to hard and soft chairside reline material in two concentrations (2% wt. and 4% wt.) while an unmodified group of each liner acted as a control, (n = 10). Disc-shaped (10 × 1.3 mm) specimens of hard denture reline (N = 60) and soft denture reline (N = 60) materials were prepared (30/test). A noncontact profilometer was used for surface roughness measurement. A colony-forming unit (CFU/mL) was used to evaluate Candida albicans adhesion. Data was analyzed using ANOVA and a post hoc Tukey's test (α = 0.05). Results: No significant change in surface roughness was observed with nano-ZrO₂ addition; however, the control groups showed the highest value while 2% nano-ZrO₂ showed the lowest value. In comparison to the control groups, nano-ZrO₂ addition to the hard and soft liners significantly reduced Candida albicans adhesion (p < 0.001), regardless of the concentration. Conclusion: Incorporating nano-ZrO₂ into hard and soft liner had no effect on surface roughness while its addition reduced Candida albicans adhesion. Using chairside soft and hard liners containing nano-ZrO₂ is recommended to reduce the incidence of denture stomatitis (DS) among denture wearers.