Effect of incorporating BAG into adhesive on Microtensile Bond Strength

Objectives: Bioactive glass (BAG) has been proposed as an additive to dental adhesives and composites due to its potential antibacterial and remineralizing effects. Our objective was to incorporate a sol-gel processed BAG into a commercial self-etch adhesive and evaluate its microtensile bond strength to dentin compared to unmodified adhesive.
Methods: Extracted human molars stored in 1% chloramine T were prepared to create a flat dentin occlusal surface and randomly divided into three groups (n=5). The 3 groups to be tested differed on the basis of the adhesive component: 1) control-unmodified adhesive; 2) 5 wt% BAG (65% SiO₂, 31% CAO and 4% P₂O₅); 3) 10 wt% BAG. Clearfill SE Bond (Kuraray) was applied as per manufacturer instructions. Filtek Supreme (3M/ESPE) was built up in 2x2mm increments and cured for 20 sec each. Teeth were stored for 24 hours in distilled water at 37^oC, sectioned into approximately 1mm x 1mm sticks, and subjected to microtensile bond strength testing. Data was evaluated using one-way ANOVA/Tukey’s (p≤ 0.05).
Results: Please see attached table.
Conclusions: The addition of 5 wt% BAG to Clearfill SE adhesive decreased the microtensile strength when compared to the commercial adhesive control group. However, there was no negative effect found on microtensile bond strength when adding 10 wt% BAG. This demonstrates that viable adhesive using Clearfil SE can be made through the incorporation of BAG at 10 wt% without adversely affecting bond strength. This may lead to the development of novel adhesives that reduce recurrent marginal caries due to BAG’s proven antimicrobial properties.