Abstract A green synthesis method was developed for silver nanoparticles (AgNPs) using Ficus microcarpa leaf extract as a natural and cost-effective reducing agent. The obtained AgNPs were characterized by UV–visible spectrophotometry, zeta potential analysis, transmission electron microscopy (TEM), and fourier transform infrared (FTIR) spectroscopy. Their antibacterial activity against Streptococcus mutans (ATCC 25175), a major cariogenic bacterium, was evaluated using an in vitro tooth cavity model. Thirty-six sound third molars were inoculated with S. mutans and treated with either the synthesized AgNPs, 0.2% chlorhexidine digluconate, or left untreated. Antibacterial efficacy was determined through agar well diffusion and TEM imaging. The AgNPs were predominantly spherical (8–38 nm) with moderate stability and demonstrated dose-dependent antimicrobial activity, showing maximum inhibition at 25 µg/mL. TEM confirmed AgNP interaction with bacterial membranes and intracellular penetration. Both treatment groups significantly reduced bacterial colony counts compared with controls ( P ≤ 0.001). These results demonstrate the potential of Ficus microcarpa -derived AgNPs as effective and sustainable tooth cavity disinfectants, integrating green chemistry principles with nanotechnology to prevent secondary caries.
Elgamily et al. (Tue,) studied this question.