Purpose: To examine the effect of applying different forms of remineralising agents during a pH-cyclinge on the bond strength of a universal adhesive applied in the etch-and-rinse mode and the types of fractures that occur after shear bond-strength testing.
Materials and Methods: 84 human molars were divided into seven equal groups. Groups 1 (intact enamel) and 2 (artificially demineralised enamel) served as the positive and negative controls, respectively. In the experimental groups (3-7), the enamel was treated using remineralising agents during a 14-day pH-cycling protocol. Group 3: fluoride gel; group 4: fluoride varnish; group 5: Tooth Mousse; group 6: MI Paste Plus; group 7: MI Varnish. Afterwards, the molars’ crowns were sectioned off, and a universal adhesive (G2-Bond Universal) was applied to the buccal surfaces of these samples using etch-and-rinse mode. Nanohybrid resin composite restorations (G-aenial Posterior) were then placed, and shear bond-strength testing was performed. The effects of remineralisation agents on artificial carious lesions were evaluated using scanning electron microscopy/energy-dispersive analysis.
Results: The fluoride varnish and MI varnish groups show statistically significantly lower shear bond strengths compared to the positive control group (p0.001). The bond strength to all remineralising agents was higher than that of the negative control group. All tested agents promoted remineralisation in demineralised areas of the enamel surface.
Conclusions: Remineralisation agents in forms other than varnish do not negatively affect the shear-bond strength to enamel surfaces. Keywords: adhesion, bond strength, remineralising agents, SEM-EDX analysis