Effect of incorporating bioactive glass filler in resin infiltrant on the microhardness of demineralized enamel

Objective: This study aimed to evaluate the effect of incorporating different concentrations of 45S5 bioactive glass (BAG) as a filler into a resin infiltrant on the microhardness of demineralized enamel.Methods: Forty bovine enamel samples were subjected to a pH-cycling protocol to induce artificial caries lesions. The teeth were randomly assigned to four groups (n = 10), based on the remineralizing treatment applied: G1: the commercial ICON® resin infiltrant (control); G2 and G3: experimental resin infiltrants containing 5 wt% (G2) and 2 wt% (G3) 45S5 bioactive glass; and G4: a filler-free resin infiltrant. Vickers microhardness was measured at depths of 50, 100, and 150 µm. The data weer analyzed using two-way ANOVA (α=0.05).Results: Both the type of resin infiltrant and lesion depth significantly influenced enamel microhardness (P<0.001). ICON® consistently demonstrated the highest microhardness, significantly outperforming the other groups at all evaluated depths (P < 0.05). Microhardness increased with depth in all groups, with significant differences observed between 50, 100, and 150 µm depths (P < 0.05). Incorporation of Bioglass® 45S5 into the resin infiltrant was effective in enhancing microhardness, as compared to unfilled resin. The 5% concentration of Bioglass® 45S5 also caused a significant rise in microhardness compared to the 2 wt% at 50 µm depth (P<0.05).Conclusions: The commercial resin infiltrant (ICON®) consistently achieved the highest microhardness at all depths. The incorporation of Bioglass® 45S5 enhanced microhardness, with the 5 wt% group exhibiting superior performance compared with the 2 wt% group and the filler-free control.