Research on the mechanical, antibacterial properties and antibacterial mechanism of ZIF-8 and h-BN with PMMA denture base resin

OBJECTIVE: This study aimed to enhance the PMMA denture base by incorporating nanomaterials to address fracture susceptibility and stomatitis. The differential effects of three-dimensional (3D) ZIF-8 and two-dimensional (2D) h-BN on the mechanical and antibacterial properties of PMMA were systematically evaluated to identify the optimal modification strategy. METHODS: ZIF-8 and h-BN were incorporated into PMMA at 0.125-0.225 wt%. Composites were evaluated for their mechanical properties (flexural strength, elastic modulus, compressive strength, Vickers hardness), antibacterial activity against C. albicans, S. mutans, S. aureus, and E. coli (via colony counting, crystal violet, and live/dead staining assay), cytotoxicity (CCK-8 and live/dead staining), color, hydrophilicity, and antibacterial mechanisms against C. albicans. RESULTS: The optimal filler concentration was 0.175 wt%, which maximized the flexural strength and elastic modulus of the PMMA denture base. All materials demonstrated concentration-dependent antibacterial activity without compromising cytocompatibility, color, or hydrophilicity. ZIF-8@PMMA showed superior antibacterial efficacy compared with h-BN@PMMA, despite equivalent mechanical performance. Mechanistic analysis revealed that ZIF-8 disrupts thiamine and glutathione metabolism in C. albicans, whereas h-BN affects fatty acid degradation and tyrosine metabolism. CONCLUSION: Both ZIF-8 and h-BN significantly improve the mechanical and antibacterial properties of PMMA while preserving its color, hydrophilicity, and biocompatibility. ZIF-8 is identified as the superior filler material for dental applications.