Jamila Nuwayji Agob¹ , Neven Saad Abdou², Essam El Saeid Al-Wakeel^{3 1. Msc candidate at Dental Biomaterials Department-Mansoura University. 2. Lecturer at Dental Biomaterials-Mansoura University. 3. Professor at Dental Biomaterials-Mansoura University.} Abstract: Purpose: This study was conducted to evaluate the remineralizing ability of caries-affected dentin treated with casinephosphopeptide-amorphous calcium phosphate and its influence on the fluoride release and micro-shear bond strength of resin modified glass ionomer cement to dentin. Materials and methods: Dentin surfaces of 45 human posterior teeth were used in the study. The teeth were divided into three equal groups (15 specimens each) for evaluating degree of mineralization, fluoride release and micro-shear bond strength of resin modified glass ionomer cement to dentin, each group was subdivided into three subgroups (n=15); control group, artificially-demineralized group and remineralized group. For the degree of demineralization and remineralization assessment, 15 rectangular specimens of 5 mm in length and 2 mm width were prepared and divided according to group's classification. The degree of mineralization was measured by Fourier Transformation Infrared spectroscopy (FTIR). For evaluation of fluoride release 15 disc-shaped of RMGICs (4 mm in diameter and 2 mm in thickness) were bonded on flat dentin disc of 5 mm in diameter and 1 mm in thickness and divided according to the groups. Fluoride release was tested using Ion chromatography. For micro-shear bond strength test 15 disc-shaped dentinal specimens bond to RMGIC were prepared and divided in to the three groups.   All groups were conditioned with polyacrylic acid. Then, tygon tubing were placed over dentine surfaces, filled with RMGIC, and mixed as recommended by the manufacturer, light cured and stored in distilled water at 37° C, for 24 hours, then micro-shear bond strength was evaluated. Micro-shear bond strength was tested using Universal Testing Machine. Means and standard deviations of degree of mineralization, fluoride release and micro-shear bond strength to dentin of different groups were calculated. Data were statistically analyzed. Results: Demineralized group treated with CPP-ACP showed a significant increase in the degree of mineralization and fluoride release mean values than those of the demineralized ones. Moreover, a significant difference among the values of micro-shear bond strength to dentin of the three tested groups was detected. Conclusion: Casinephosphopeptide-amorphous calcium phosphate is an effective treatment to enhance the degree of mineralization, fluoride release and micro-shear bond strength of caries-affected dentin to RMGIC.