Correlations between the concentrations of fluoride and some other constituents in tea infusions and their possible dental caries-preventive effect.

Tannic acid, total, complexed and ionized fluoride, calcium, total phosphate, zinc, aluminium, copper, iron, mercury and manganese were determined in infusions prepared from some or all of 30 brands of tea. Mercury and copper were not detected. Significant positive correlations were observed between fluoride, aluminium and manganese. The low reactivity of fluoride in tea infusions with powdered hydroxyapatite compared with that in dilute sodium fluoride solutions may be in part explained by the presence of aluminium and manganese.