Abstract
100 mg of 100-150 mesh powdered enamel was treated with 10ml. of 2% sodium fluoride solution (2% NaF group) or 0.2, 2, 4, 8 and 16% stannous fluoride solution (0.2-16% SnF2 group) respectively 5 minutes at 20°C. The treated sample was decalcificated by 200 ml. of N/5 acetate buffer (pH 4.0) for 2 hours at 37°C, stirring with a magnetic stirrer. Amounts of calcium and phosphate disolved out of the sample were determined after each run in 7 successive decalcification runs. For obtaining the initial content of calcium and phosphate in the sample, 100mg of powdered enamel of each group was disolved in 2N nitric acid and then total acidsoluble-calcium and phosphate were determined. Calcium was determined with EDTA-2Na titration method, and phosphate with molybdium-vanado phosphate method. The decalcification rate was also investigated.
Conclusions as follows
1) The enamel solubility in NaF and SnF2 group were less than that of control, and the difference were more marked during the earlier runs of decalcification.
2) 2%, 4% and 8% SnF2 group seemed to demonstrate the lower acid-solubility when compared with 2% NaF group. 0.2% SnF2 group was inferior in resistance to acid than to other higher concentration groups, and there was no definite difference between this group and NaF group.
In 16% SnF2 group, the disoved Ca and P from samples was rather higher than other lower concentration (2 or 4%) group during the earlier runs of decalcification.
