The aim of this in vitro study was to analyze the composition of human tooth enamel in terms of three components, Ca, P, and F after demineralization and remineralization in acid buffer solution. A total of 8 human premolars without any defects and cracks were selected and buccal and lingual sides of the teeth were cleaned with an ultrasonic device and pumice without fluoride 5$ imes$5mm windows were opened, and other areas were completely covered with 3-coats of nail varnish to prevent from being in contact with demineralized and remineralized solutions. After demineralization process, each tooth was sectioned into two slices, highly polished one of them with$gamma$-alumina, and then analyzed the composition of the demineralized tooth with EPMA(electron probe micro-analyzer). The other slices were put into the remineralized solution for 10 days, polished, and analyzed in the same manner. These data were statistically analyzed with one sample t-test(p<0.05). The results were as follows. 1. Normal tooth enamel consists of 49.76% Ca, 39.80% P, and 0.28% F. 2. After demineralization, percentage of Ca and P ratio were decreased by about 5.57 and 5.07% respectively. Percentage of F ratio was also decreased by about 0.01%, which was not statistically significant. 3. After remineralization, percentage of Ca, P increased about by 4.47 and 4.35% respectively Percentage of F decreased by about 0.01%, which was not statistically significant. In conclusion, remineralized solution used in our study has the potential to induce the uptake the Ca and P into the pore sites of the demineralized enamel. But, in the oral cavity. there were rapid temperature change, organic matrix that inhibits the movement of the ions, and limitation of continuous contact with this remineralized solution. Therefore, further in vivo study is necessary.