Abstract
Human flat dentin surface ground with SiC paper (#180, 600 or 2000) was treated with one of 4 all-in-one adhesive systems (AP Plus, i Bond, G-Bond, Xeno CF Bond_II_). The bonding interface was ultrastructurally observed in TEM to clarify the effect of smeared layer on the bonding performance of all-in-one adhesive susyems.