Abstract
Using repeated acid decalcification, the solubilit of treated powdered enamel in acetic acid was compared between stannous fluoride and sodium fluoride.
100 mg of 100 or 150 mesh powdered enamel was treated with 10 ml of 2% sodium fluoride solution (NaF) and 4% or 8% stannous fluoride solution (SnF2) for 20 minutes at 20°C. After washing with distilled water, 10 ml of N/5 acetate buffer was added to the protected enamel sample, and then the decalcification was carried on as follows. The decalcification procedure was repeated ten runs, stirring 5 seconds per minute (600 rpm) for 20 minutes at 37°C in each run. Amounts of calcium and phosphate disolved from a sample were determined in each run. The control group was treated by the same procedure except fluoride treatment.
Following conclusions were obtained:
1. The stirring method in the decalcification procedure was very important for evaluating effects of different reagents on powdered enamel.
2. SnF2 group had the lowest solubility of enamel when tested by author's decalcification method, and 8% SnF2 group appeared to the less soluble than 4% SnF2 group. (Fig. 1, 2 and 3.)
3. As for Ca/P ratio, they were 2.3 or 2.4 in NaF group, 2.5 or 2.7 in SnF2 group and 2.1 or 2.2 in control group in the earlier runs of 10 successive decalcification. There were statistically significant difference between these three group. (Fig. 5, Table. 1.)
And the variation coefficient of SnF2 group in the earlier decalcification runs was shown to be larger than that of NaF group. (Fig. 4.). It was suggested that the made of action on enamel structure might be different between NaF and SnF2.
