Enhanced Mechanical and Antifungal Properties of Polymethyl Methacrylate Denture Bases by Incorporation of Silver-Doped Mesoporous Silica Nanocomposites Modified by Two Coupling Agents.

Abstract

The objective of this study was to optimize the composition and loading of silver-doped mesoporous silica nanoparticles (Ag/MSNs) within the poly(methyl methacrylate) (PMMA) denture base to enhance mechanical properties, antifungal activity, and maintain biocompatibility. Silica nanoparticles (SBA-15) were synthesized and functionalized with either diaminosilane (PC1200) or gamma-methoxysilane (γ-MPTS) coupling agents prior to silver impregnation. The functionalized and unmodified SBA-15 were then loaded with silver nanoparticles via chemical reduction. These Ag/MSN-modified PMMA composites were fabricated at different nanoparticle loadings (0.1, 0.5, 1, and 1.5 wt%) and characterized for their physical, mechanical, antimicrobial, and biocompatibility properties. The incorporation of Ag/MSNs significantly improved the mechanical properties and antimicrobial activity of the PMMA-based dental prosthesis material without compromising biocompatibility. The modification of Ag/MSNs particles by both types of coupling agents fortified the material's mechanical properties, sustained water solubility and release of silver nanoparticles, thereby providing better biocompatibility for the synthesized nanocomposites. This phenomenon was more pronounced in the amino-silane coupling agents equipped with diamine groups. The findings of this study demonstrated that an increase in the concentration of Ag/MSNs particles in the PMMA polymers up to 1.5 wt% resulted in the deterioration of the mechanical properties, reducing water sorption and solubility, but enhancement of antifungal activity. A concentration of 0.5 wt% silver-doped mesoporous silica nanoparticles modified by amino-silane or gamma-methoxysilane coupling agents can be considered the optimal concentration for incorporation into PMMA denture bases, resulting in enhanced mechanical and antifungal properties while preserving biocompatibility.