Therapeutic effects of a 45S5 bioactive glass–modified self-etch adhesive on sound and artificially demineralized dentin: mechanical, interfacial, and chemical analyses

To evaluate the effects on the bonding interface and remineralization potential of a self-etch adhesive containing 10% (w/v) 45S5 bioactive glass (BAG) in sound dentin (SD) and artificially demineralized dentin (ADD). Sound third molars were selected and stored in 0.01% thymol solution, and part of them was subjected to a pH-cycling protocol to induce controlled demineralization. The experimental groups were: SD, ADD, BAG + SD, and BAG + ADD. Microtensile bond strength (n = 8) was assessed after 24 h and six months. Nanoleakage (n = 3), micropermeability (n = 3), Knoop microhardness (n = 3 after 24 h and three months), and FT-IR spectroscopy (n = 3 immediately and after 30 days) were also performed. All specimens were stored in artificial saliva at 37 °C with monthly renewal. Data were analyzed using ANOVA and Tukey's test (p < 0.05). The BAG + ADD group maintained bond strength after 6 months (p = 0.887). BAG reduced nanoleakage in both SD and ADD. Micropermeability showed no fluorescein uptake in SD, and reduced absorption in ADD when treated with BAG. After 3 months, BAG + ADD significantly increased microhardness at all tested depths, while BAG + SD showed improvements at 70 µm and 100 µm (p = 0.006 and p = 0.015, respectively) FT-IR analysis showed phosphate and carbonate bands in BAG-containing adhesives, with increased definition after 30 days, indicating time-dependent ion release and apatite maturation. Incorporation of BAG into a self-etch adhesive (Clearfil SE Bond) preserved long-term bond strength, enhanced dentin microhardness, promoted mineral precipitation at the adhesive interface, and improved hybrid layer, sealing-particularly in artificially demineralized dentin.