Orthodontists use a self-etching adhesive system when attaching brackets to enamel. The purpose of this study was to evaluate the erosion effects of common clinically used adhesive systems on human enamel surfaces by atomic force microscopy (AFM). Four commercially available adhesive systems (i. e., Kurasper F, Beauty Ortho Bond, Orthophia LC, and Transbond XT) were applied to ground enamel surfaces of extracted human teeth. Enamel surface roughness (ESR), absolute depth profile (ADP), and surface hardness were evaluated by AFM. The ESR and ADP were significantly higher after the pretreatment with the phosphoric acid-etching adhesive system than after the pretreatments with the three self-etching adhesive systems. The surface nanohardness decreased after the pretreatment with the phosphoric acid-etching adhesive system but increased after the pretreatments with the self-etching adhesive systems. These results suggest that the use of a self-etching primer for enamel conditioning might prevent decalcification caused by phosphoric acid etching.