Objective: To explore the long-term in-vivo effect of different dental restorative materials on the surrounding enamel and dentin, in primary molars. Method and Materials: Sixteen naturally exfoliated primary molars restored with amalgam, compomer, and glass-ionomer cement were collected after 2 to 5 years of function in the mouth. Four intact molars served as control. The teeth were sliced buccolingually and the ion content in the restorative material, the enamel, and the dentin surrounding the restoration was determined using a scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS) program. Results: Amalgam released copper to the enamel and dentin causing a bluish discoloration. No traces of mercury or other ions were detected in the enamel or dentin. The enamel and dentin surrounding the restoration showed reduced inorganic components and increased organic components. The enamel and dentin surrounding the compomer restoration showed similar to amalgam reduction in inorganic components and increased organic components. Traces of fluoride, aluminum, and silicon were found. The enamel and dentin of teeth restored with glass-ionomer cement showed the least reduction in inorganic components, with higher fluoride content and traces of aluminum, silicon, and strontium. Conclusion: This long-term in-vivo study showed release of copper ions from amalgam material to the enamel and dentin, but no traces of mercury. Amalgam and compomers showed no remineralization effect on the dentin surrounding the restoration. Glass-ionomer restorations showed remineralization effect on the tooth components and migration of inorganic ions from the enamel and dentin to the material. Schlagwörter: amalgam, compomer, dentin, enamel, glass-ionomer, primary molars