Dentin adhesives application deviations: Effects on permeability and nanoleakage

Abstract

The purpose was to evaluate the effect that deviations from the recommended protocol of a two-step etch-and-rinse adhesive system has on permeability and nanoleakage. One hundred and twenty dentin disks were treated with a two-step etch-and-rinse adhesive system, according to the manufacturer’s instructions, or using five simulated deviations from the recommended protocol: applying potassium oxalate, reducing the application time of the adhesive, avoiding adhesive drying, aggressively drying the adhesive, and double application of adhesive. Kruskal–Wallis and Tukey’s post hoc comparisons were used to evaluate the permeability reduction (α=0.05). Twelve additional dentin disks were prepared for transmission electron microscope (TEM) analysis of nanoleakage. Aggressive drying, adding additional layers of adhesive or using oxalate reduced dentin permeability and yielded a better infiltration of the hybrid layer, whereas reducing the application time or less drying the adhesive did not to reduce dentin permeability, caused extensive nanoleakage, showing immediate compromised dentin sealing.