Inner carious dentin after cleansing and the dentin-resin interface were observed with scanning electron microscopy. Results suggested that, similar to 10% citric acid-3% ferric chloride solution, 10% ethylenediaminetetraacetic acid may thoroughly remove the smear layer on the surface of inner carious dentin and make it possible for the dentinal bonding agent to penetrate the cleansed dentin to form an acid-proof layer and dense resin tags. These changes may improve the bond strength as well as tubule aperture seal.Ethylenediaminetetraacetic acid is not destructive to collagen, and may be of negligible toxicity to the pulp of intact dentin.