Abstract: The enamel surface hardness determination plays a key role in surface abrasion a resin composite bond strength. The aim of this study was to investigate the enamel surface hardness after remineralization of white spot lesions using casein phosphopeptide amorphous calcium phosphate (CPP-ACP), fluoride and casein phosphopeptide amorphous calcium phosphate fluoride (CPP-ACPF). Materials and Methods: A 36 bovine anterior teeth were chosen and after decoronization, the teeth were mounted in acrylic resin and their baseline surface hardness was measured. Samples were then demineralized and their surface hardness was measured. The teeth were then divided into three groups and subjected to surface treatment with CPP-ACP, CPP-ACPF and fluoride mouthwash. The surface hardness was measured and the data were analyzed using SPSS software. Results: Paired t-test showed that surface hardness significantly changed after demineralization (P<0.001) and after treatment with CPP-ACPF (P<0.001) and fluoride (P=0.005), however: the change was not significant after treatment with CPP-ACP (P=0.155). Conclusions: The obtained results indicated that treatment with fluoride and CPP-ACPF may increase the surface hardness of demineralized enamel. Manuscript profile