Abstract
It has been reported by many authors that several fluoride compounds have caries inhibiting effect. We try to study the influence which the difference of chemical properties of these fluoride compounds may exert on fluoride uptake and solubility reducing effect on enamel powder.
Human enamel powder was treated with eighteen different fluoride solutions F 1000 ppm, pH 4.0, and each was tested about fluoride uptake and reduction of enamel solubility in acetate buffer solution. Consequently, when enamel powder was treated with the solutions of alkaline fluoride compounds, fluoride uptake was much higher than others. But concerning to solubility reducing effect on enamel, heavy metal fluoride compounds especially those which the metal made complex ion with fluorine in water, were superior to others.
From these results, in order to study concerning to these compounds in detail, fluoride compounds which had different ions in the resolved aqueous solution were selected (SnF2, NaF, Na2PO3F, Sn2P2O7-NaF). And they were tested about fluoride uptake and solubility reducing effect on enamel powder under different conditions of pH (pH 3, 4, 5) and fluorine concentration (F 500, 1000 ppm).
At pH 3.0, sodium fluoride was most effective on reducing of enamel solubility, but at pH 4.0 and 5.0, tin containing compounds were the best at both fluorine concentration. The compounds except stannous fluoride was greatly affected by pH, and solubility reducing effect decreased with the rise in pH. But stannous fluoride was hardly affected by pH and the enamel destruction during fluoride treatment was also smaller than others.
From these results, we conclude that the existence of heavy metal in addition to fluorine is necessary for the solubility reducing effect of early decalcification period. Especially, stannous fluoride have prominent effectiveness on solubility reduction on enamel and it is not affected by pH.
