Magnesium (Mg), strontium (Sr) or fluoride (F) ions have been shown to affect in vitro activities of bone cells and in vivo mineralization. The purpose of this study was to investigate the effect of Mg, Sr and F ions on the activities of odontoblast-like cells (MDPC-23) using an in vitro cell culture model. Mg, Sr or F ions were added to the medium in the following concentrations: Mg -1, 5, 10 mM; Sr -0.05, 0.1, 0.3, 1 mM; F-0.005, 0.01, 0.05, 0.1 mM. Results were observed after 1, 7 and 14 days using Von Kossa staining, scanning and transmission electron microscopy. Preliminary results showed the following: Mg ions demonstrated a positive effect at low concentrations and a negative effect at high concentrations; Sr ions demonstrated a positive dose dependent effect up to a concentration of 0.1 mM and a negative effect at higher concentrations; and F ions demonstrated a positive dose-dependent effect up to a concentration of 0.005 mM and inhibitory effects at higher concentrations. This preliminary study showed that the positive or negative effects of Mg, Sr or F ions on odontoblastic activities (proliferation and mineralization) depend on their concentration levels in the environment.