: Caries is one of hard tissue disease that caused by the activity of many bacterias and it is signed by the present of demineralization. There are two kind of demineralization, the first is demineralization involving bacteria and demineralization involving acid agent directly. It was written in some result survey that the prevalence of caries in children is rising by the age of the children, it is caused by some factors, there are the children’s tooth structure is thinner and also many children like to consume milk, tea, and soda. The demineralization process is not always end up with caries in children’s tooth, but with the present of remineralization process and with the help from its compositions, the demineralization could be inhibit or either eliminate so that the remineralization process could happen and help to stronger the children’s tooth. Purpose : The aim of this research is to tested the hardness difference of deciduous tooth enamel between before and after soaking in milk, tea, and soda. Methode : The type of this research is experimental laboratory, and samples used for this research are deciduous teeth with some requirements applied the inclusion and exclusion criterias. The number of samples are six teeth for each four different variable, three are dependent variables, and one is control variable. Result : The data from the research were analized using One-Way Anova test. The result of One-Way Anova test showed that the significancy number is p=0.000 (p<0.05), indicates that there is significant change of enamel hardness between before and after soaking in milk, tea, and soda. Conclusion : The hardness number is increasing in the sample soaking with milk and tea, and decreasing in the sample soaking with soda