To simulate a clinical cavity wall with the inner layer of carious dentin preserved, an artificially demineralized layer was made on the axial wall class V cavities of monkeys by a quick decalcifying solution. The cavities were then restored with a chemically adhesive composite resin after etching with a 40% phosphoric acid jelly etchant. Comparison of the Knoop hardness, the calcium concentration, and the scanning electron microscope observation of the dentin at the axial wall revealed that the dentin, demineralized by etching, was completely remineralized after 4 months.