Influence of zein-coated magnesium oxide nanoparticle reinforcement on the flexural strength of polymeric denture base resins.

Background/objectives: Conventional polymethyl methacrylate denture base resins exhibit limitations in mechanical durability and microbial resistance. Zein-coated magnesium oxide nanoparticles (zMgO NPs) have previously demonstrated antimicrobial activity when incorporated into dental polymers. However, their influence on mechanical performance has not been thoroughly characterized. This study investigated whether integrating zMgO NPs affects the flexural strength of heat-polymerized and autopolymerizing acrylic denture base materials. Methods: Five commercially available polymethyl methacrylate resins (three heat-cured and two self-cured) were evaluated. Sixty samples of each type were randomly assigned to four groups based on nanoparticle concentration: 0%, 0.3%, 0.5%, and 1% by weight. Sample fabrication and testing were performed in accordance with ISO 20795-1 for denture base polymers. Flexural strength was assessed using a three-point bending test. Data were analyzed using two-way analysis of variance followed by Results: Samples containing 0.5% and 1% zMgO NPs demonstrated significantly higher flexural strength than controls, whereas the 0.3% zMgO NPs groups showed no statistically significant difference compared to the control. Conclusions: Incorporation of zMgO NPs maintains the flexural performance of denture base polymers. Higher nanoparticle loadings produced significantly higher flexural strength, suggesting potential for multifunctional denture materials with improved structural durability. Future work should include long-term aging and simulated oral conditions to confirm clinical applicability.