Effect of adding pomegranate peel extract-loaded mesoporous silica on some mechanical and antimicrobial properties of heat-cured acrylic resin

Abstract

Background: Candida albicans (C. albicans) is the predominant microorganism responsible for denture stomatitis. Recent research emphasizes using natural antimicrobial agents in denture base production to prevent C. albicans growth, utilizing economic waste materials while minimizing the risk of developing resistant pathogens. The antibacterial effects of pomegranate peel extract (PPE) have been demonstrated against a variant of bacteria and fungi, with a special focus on C. albicans. Objectives: This study aimed to analyze the impact of PPE loaded into mesoporous silica nanoparticles (PPE@MSNs) on surface and bulk mechanical properties of heat-cured polymethyl methacrylate (PMMA) and to investigate its antifungal activity against C. albicans. Patients and methods: PPE was prepared, encapsulated in functionalized mesoporous silica nanoparticles (MSNs), and characterized using transmission electron microscopy before being added to PMMA. Fifty samples were divided into five groups (n = 10) based on PPE@MSNs concentrations (0, 0.5, 1, 2.5, 5 wt.%). PP extract, MSNs, PPE@MSNs, and all studied groups were characterized using Fourier transform infrared spectroscopy, radiography diffraction, and scanning electron microscopy. After the curing of specimens, flexural strength, fractographic analysis, Vickers microhardness, and surface roughness were assessed. Antibiofilm activity was evaluated using crystal violet staining, and biofilm quantification was performed with a microplate reader for antifungal activity against candidal biofilm formation. Results: Flexural strength and microhardness have been improved with increasing concentrations of PPE@MSNs (0.5, 1, and 2.5 wt.%) and surface roughness also increased gradually with increasing the concentration. However, at a concentration of 5 wt.%, flexural strength and microhardness were decreased, while surface roughness was increased. PMMA modified with PPE@MSNs demonstrated a positive antifungal effect on inhibiting C. albicans biofilm formation at concentrations (0.5, 1, and 2.5 wt.%) compared to the control group, especially at 0.5 wt.%, but presented no effect at 5 wt.%. Conclusion: PPE@MSNs can improve the antifungal activity against Candida albicans and enhance the mechanical properties, including flexural strength and microhardness, of heat-cured PMMA at 0.5, 1, and 2.5 wt.% concentrations.