Inhibitory Effects of Surface Pre-Reacted Glass Ionomer Filler Eluate on Streptococcus mutans in the Presence of Sucrose

Abstract

The surface pre-reacted glass ionomer (S-PRG) filler is a type of bioactive functional glass that releases six different ions. This study examined the effects of the S-PRG filler eluate on Streptococcus mutans in the presence of sucrose. In a solution containing S. mutans, the concentrations of BO33−, Al3+, Sr2+, and F− were significantly higher in the presence of the S-PRG filler eluate than in its absence (p < 0.001). The concentrations of these ions further increased in the presence of sucrose. Additionally, the S-PRG filler eluate significantly reduced glucan formation by S. mutans (p < 0.001) and significantly increased the pH of the bacterial suspension (p < 0.001). Bioinformatic analyses revealed that the S-PRG filler eluate downregulated genes involved in purine biosynthesis (purC, purF, purL, purM, and purN) and upregulated genes involved in osmotic pressure (opuAa and opuAb). At a low pH (5.0), the S-PRG filler eluate completely inhibited the growth of S. mutans in the presence of sucrose and significantly increased the osmotic pressure of the bacterial suspension compared with the control (p < 0.001). These findings suggest that ions released from the S-PRG filler induce gene expression changes and exert an inhibitory effect on S. mutans in the presence of sucrose.