Effect of Bioactive Glass on Microshear Bond Strength of Composite Resin to Dentin Using a Universal Adhesive with Different Application Modes and Storage Times.

Abstract

Objectives: This study evaluated the effect of bioactive glass (BAG) in different forms on microshear bond strength (µSBS) of composite resin to dentin using a universal adhesive in self-etch (SE) and etch-and-rinse (E&R) modes after different storage times. Materials and Methods: In this in vitro study, 120 extracted human third molars were sectioned 3mm occlusal to their cementoenamel junction to expose dentin. The teeth were then randomly assigned to three groups (n=40): (I) 20% BAG suspension for dentin pretreatment, (II) 1% BAG-modified adhesive (G2-Bond Universal), and (III) BAG-free control group. Each group was subdivided based on the adhesive application mode (SE or E&R) and storage time (immediate at 24 hours, or delayed at 3 months), with 10 teeth per each subgroup. The µSBS was measured by a universal testing machine. Data were analyzed by three-way and two-way ANOVA, followed by the Tukey's post-hoc test (α=0.05). Results: Three-way ANOVA showed significant interaction effect of BAG incorporation and storage time on µSBS (P=0.017); while other interactions were not significant (P>0.05). The effects of BAG incorporation (P=0.951) and application mode (P=0.769) were not significant on immediate µSBS (P>0.05). After 3 months, the 1% BAG-modified adhesive showed a significantly higher µSBS than the 20% BAG suspension (P=0.001) and the control group (P<0.001), with no significant effect of application mode (P=0.417). Conclusion: BAG incorporation did not affect the immediate µSBS of the adhesive but improved its long-term durability, such that the 1% BAG-modified adhesive showed the highest delayed µSBS, regardless of the application mode.