AbstractThe purpose of this investigation is to clarify the role of the component phases of dental amalgam in a corrosive environment and to analyze the corrosion products at various stages of formation predominantly by means of x‐ray diffraction methods and energy dispersive x‐ray spectroscopy. The study encompassed in vivo as well as in vitro experiments.Sn, which came from only the γ2 phase, was found to be the sole or main constituent that contributes to the formation of the corrosion products. \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm SnO} \cdot {\textstyle{1 \over 2}}{\rm H}_2 {\rm O} $\end{document} constituted the majority of the corrosion products formed in the early stages. SnO appeared in corrosion products more than 14 days old.