1) In order to give a quantitative ground to the fact that there was no preventive effect from caries of tooth powder mixed with fluoride, the following experiment was made.
2) The time process of solubility of Soda fluoride in water is shown in table I and biagram 1. it is most soluble within two minutes and then it becomes much less soluble.
3) Calcium Acid, which contains 3 % of Soda fluoride itself, was dissolved in the water. The difference in the amount of solution was remarkable, and in the former case, Soda fluoride did not show solution of the whole amount.
4) In the case of water which contains Soda fluoride mixed with 3-10 % calcium carbonate, it was found that 65.6-674 % of the calcium fluoride remains as an in soluble precipitate.
5) From tne above fact, tooth powder mixed with fluoride, which mainly contains calcium carbonate, connot be expected to produce apreventive effect against caries.
抄録全体を表示