Etching of Dentin Surface with Ammonium Citrate Aqueous Solution

New dentin etchants AC (ammonium citrate) were examined. The pH of the AC solution was 7.3-7.4, and the concentration of the solutions varied from 5% to 30%. The etching of a 10% AC solution was the most effective in improving the adhesion between the composite resin and dentin among the AC solutions employed when MTYA.G.H was used as a dentin primer. The smear layer was removed and the tubules were not generally opened with AC etching. The bond strengths to dentin etched with 10% AC were comparable with those to dentin etched with neutralized 0.5 M EDTA or EDTA 3.2. The bond strengths increased with primers MTYA.H and MTYA.G.H, in that order.