Growth inhibition of glass ionomer cements on mutans streptococci.

This study was conducted to identify the factors involved in the antibacterial activity of glass ionomer cement (GIC) on mutans streptococci. The antibacterial effect of GIC was estimated using agar plates infected with strains of S. mutans and S. sobrinus. The effect of pH and fluoride release of GIC on mutans streptococci was studied under acid and neutral pH. Strains of S. sobrinus were more sensitive to GIC antibacterial activity, the difference being statistically significant (P < 0.001). The GIC Fuji II LC, Fuji II type II, Vitremer, Vitrebond, and Ketac-Cem were the most active materials in this study. The inhibition activity was associated with GIC fluoride release; 140 +/- 25 ppm were required to inhibit S. sobrinus 6715. Inhibition activity was not associated with changes in pH after setting of these materials.