The role of magnesium in the aetiology and prevention of caries: some new findings and implications.

While some epidemiological studies seem to indicate that a high intake of magnesium should be associated with a low prevalence of dental caries, the results of experimental studies are mainly equivocal. Magnesium is probably not bound to the apatite lattice of dental enamel or dentine, or it is bound to a small degree only. It is mainly located in the hydration layer of the apatite crystallites. In the dental caries process it is preferentially dissolved together with the carbonate of the mineral phase. It is not known to what extent feasible dietary changes can modify tooth magnesium content during pre-eruptive tooth development. Animal experiments indicate that the elevation of dietary magnesium alone after tooth eruption has no definite capacity to modify the occurrence of dental caries. When fed in combination with small fluoride supplements in the diet magnesium and fluoride may support each other in preventing various calcium salt imbalances such as dental caries, arteriosclerosis and nephrocalcinosis. Although some recent in vitro findings indicate that extra magnesium in the fluid environment of cariogenic streptococci may protect them against the inhibitory action of fluoride, such magnesium changes do not seem possible in the human mouth under present or envisaged dietary conditions.