Objective      To investigate the remineralization potential of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on the surface microhardness of human enamel eroded by a carbonated soft drink.       Methods      Fifteen third molars were collected at clinic and were processed into 30 enamel slabs. The enamel slabs were randomly divided into 3 groups (n=10): deionized water group

CPP-ACP group

and fluoride vanish group. Each specimen was first immersed in a Coca-Cola drink for 2 min

7 times a day for 7 d. Then the specimens were subjected to 3 different remineralization protocols

deionized water

CPP-ACP and fluoride vanish. Vickers microhardness (SMH) measurements were obtained at baseline

after the Coca-Cola drink erosion

and after remineralization stage. The enamel specimens were analyzed by scanning electron microscopy (SEM).       Results      Enamel hardness was significantly decreased after immersion in a Coca-Cola drink (P0.05). The SMH of the enamel slab treated with CPP-ACP and fluoride vanish was significantly increased compared with that of the negative control (P0.05)

and there was significant difference between the 2 former groups (P0.05). SEM demonstrated that there were lots of minerals deposited on the surface of enamel of CPP-ACP and fluoride vanish groups.       Conclusion      CPP-ACP promotes minerals to deposit on the demineralized enamel surface to increase the SMH of the eroded human enamel

showing the remineralization potential.