Effect of the Additional Application of a Resin Layer to Single-step Dentin Adhesives

摘要

The purpose of this study is to examine that an additional coat of intermediate hydrophobic resin can increase the bond strength to dentin by reducing the permeability of single-step adhesives and to determine the application mode of IRL (Intermediate Resin Layer). Three single-step self-etch adhesives (Adper Prompt L-Pop; PL, One-Up Bond F; OU, and Xeno III; XE) were used in this study. In case of each adhesive there were ten groups divided as the use of IRL, the mode of composite applied, and the light-cure of adhesive before IRL applied. Microshear bond strength was measured with Universal testing machine and nanoleakage within a hybrid layer was evaluated by TEM. The results indicated that bond strength of all dentin adhesives tested was increased with the use of IRL, especially when composite was applied with self curing mode and the thickness of hybrid layer was correlated with the acidity of adhesive used, and the nanoleakage represented by silver deposits and grains was observed within hybrid and adhesive layer in most of single- step adhesives.