ABSTRAKThe purpose of this study was to determine the different fluor uptake in enamel of primary teeth filled with Conventional and High Viscosity Glass Ionomer Cement. Samples in this study were 20 non-carious primary maxillary incisors. Samples were divided into 2 groups (10 samples for each group) which were: group I filled with Conventional Glass Ionomer Cement and group II filled with High Viscosity. All samples were put in saline solution for 7 days. Each sample was divided into 3 areas in 20 um2 square, making 30 data for every group. The different fluor uptake was observed with Energy Dispersive X-Ray Spectrophotometry (EDS) and the results are in graphic. T-test showed significant difference of fluor uptake in enamel of primary teeth between Conventional Glass Ionomer Cement and High Viscosity Glass lonomer Cement filling (t- 2.36, p-0.025). Fluor uptake in enamel of primary teeth filled with High Viscosity Glass lonomer Cement was much more than Conventional Glass Ionomer Cement.