Shear Bond Strength of Different Adhesives after Caries Infiltrant Application

Objectives: The purpose of this study was to investigate the influence of caries infiltrant application on the shear bond strength of different adhesives on sound and demineralized enamel. Methods: Sound and artificially demineralized (14 d, acidic buffer, pH 5.0) bovine enamel specimens were treated with a caries infiltrant (Icon, DMG), three different commercial adhesives (unfilled etch&rinse adhesive: Heliobond, Ivoclar Vivadent; filled etch&rinse adhesive: Optibond FL, Kerr; or self-etching adhesive: iBOND Self Etch, Heraus Kulzer) or a combination of caries infiltrant and adhesive. Shear bond strength of a nanohybrid-composite was analysed after thermo-cycling (5000x, 5o to 55°C) at a crosshead speed of 1 mm/min. Failure mode was inspected under stereomicroscope at 25× magnification. Results: In both sound and demineralized enamel, shear bond strength of the caries infiltrant was not significantly different from the etch&rinse adhesives, while the self-etching adhesive showed significantly lower values compared to all other groups. Pretreatment with the caries infiltrant significantly increased the bonding strength of the self-etching adhesive in both substrates and of the filled etch&rinse adhesive in demineralized enamel. While shear bond strength was not significantly different between both substrates, cohesive failures were more likely to occur in demineralized than sound specimens. Conclusion: The shear bond strength of the caries infiltrant was similar to the etch&rinse adhesives. The caries infiltrant did not impair bonding to sound and demineralized enamel, and even increased adhesion of the self-etching agent.

The first author was supported by a Swiss Federal Scholarship.