Evaluation of Bioactive Glass and Low Viscosity Resin as Orthodontic Enamel Sealer: An In Vitro Study

The study aimed to evaluate the effect of applying fluoride bioactive glass (FBAG) and Alpha-Glaze(®) (resin sealer) on the shear bond strength of orthodontic brackets to enamel bonded by Transbond XT, brushing–abrasion durability, and their protective effect against simulated cariogenic acidic attack. Materials include 135 extracted premolars that were divided into three groups—FBAG, Alpha-Glaze, and control. The shear bond strength test was measured using an Instron Universal Testing Machine. The brushing abrasion challenge took place with a tooth-brushing simulator. Transmitted light microscopy examinations were performed after the specimens were demineralized for 4 days. The results show that the shear bond strength values of the three groups did not report any statistically significant differences: FBAG (28.1 ± 5.5 Mpa), Alpha-Glaze (32.5 ± 7.4 Mpa), and control (30.7 ± 6.5 Mpa) p < 0.05. The Adhesive Remenant Index (ARI) study showed chipping of enamel in 6.6% of Alpha-Glaze and control specimens and 40% of specimens had their enamel surface covered with resin. Furthermore, 30% of the FBAG and 100% of the Alpha-Glaze sealer specimens resisted the abrasion test. In conclusion, FBAG can serve as an orthodontic-sealer capable of protecting the enamel surface surrounding orthodontic brackets. However, the Alpha-Glaze sealer did not offer the capability of protecting the enamel.