In vitro comparative evaluation of bioactive glass and fluoride varnishes on enamel remineralization of permanent teeth

Bioactive glass, a material capable of precipitating hydroxyapatite in aqueous solutions, has the unique ability to bond with both hard and soft tissues without causing rejection. This study aimed to compare the effectiveness of bioactive glass varnish to fluoride varnish in promoting enamel remineralization in extracted teeth. Thirty human premolars were collected, then cleaned and polished using a scaler. The teeth were sectioned longitudinally, and the roots were removed. The specimens were stored in a demineralizing solution to create early enamel lesions and then randomly divided into three groups: bioactive glass varnish, fluoride varnish, and a control group. The materials were applied, and all specimens underwent a pH-cycling model for 1 month. Enamel evaluation was conducted using DIAGNOdent, and SEM-EDAX to measure calcium and phosphorus weight percentages, and surface roughness was assessed. Data were analyzed accordingly. The results show that at baseline and after demineralization, there were no significant differences in DIAGNOdent readings among the three groups, but significant changes were observed within each group from baseline to after demineralization (p ≤ 0.05). After treatment, the bioactive glass varnish group showed significantly the lowest DIAGNOdent readings, followed by the fluoride varnish group, while the control group showed the highest readings (p ≤ 0.05). EDAX analysis revealed significantly higher calcium and phosphate mass percentages in the bioactive glass group compared to the fluoride and control groups (p ≤ 0.05). SEM examination demonstrated a smoother enamel surface in the bioactive glass group, mild irregularities in the fluoride group, and pronounced roughness in the control group. Both bioactive glass and fluoride varnishes demonstrated a remineralizing effect on enamel surfaces. However, the bioactive glass varnish showed superior performance, with greater mineral gain confirmed by DIAGNOdent, EDAX, and SEM analyses. These findings indicate that bioactive glass varnish may offer an effective and biocompatible alternative to fluoride varnish for managing early enamel lesions.