Surface moisture influence on etch-and-rinse universal adhesive bonding

Purpose: To evaluate whether surface moisture would influence the bonding effectiveness of universal adhesives in etch-and-rinse mode.

Methods: All-Bond Universal (AB), G-Premio Bond (GP) Prime&Bond Active (PB) and Scotchbond Universal Adhesive (SU) were evaluated. Shear bond strengths after 24 hours and 10,000 thermal cycles of universal adhesives to moist and dry enamel and dentin in etch-and-rinse mode were determined. Scanning electron microscopy observations of the adhesive interfaces were conducted.

Results: The bond durability of universal adhesive to dentin in etch-and-rinse mode was influenced by the surface moisture, unlike bond durability to enamel. The bond durability of AB and GP, but not PB and SU, to dentin in etch-and-rinse mode was different depending on the surface moisture. Surface moisture did not influence the thicknesses of the adhesive or hybrid layer of resin-dentin interfaces, but the length of resin tags in the moist group was longer than in the dry group.

Clinical significance: Some universal adhesives, with the addition of specific components and optimization of water content, can achieve stable bonds regardless of surface moisture, but the surface moisture of dentin, although not enamel, is still a significant factor for universal adhesive bonding in etch-and rinse mode.