Abstract
The fluoride acquisition in vitro by intact enamel from phosphoric acid-acidified NaF solution (500 ppm of F-; PH 5.0) and the acid solubility of the enamel were examined. Specimens were treated with fluoride mouth-rinsing solution for 30 minutes every day at 37°C during 8 weeks and immersed in artificial saliva.
The fluoride content in succesive layers of enamel was determined by using an ORION ion meter (model 801) and fluoride electrodes. The calcium content was determined by Yanagisawa's method using Plasmo Corinth B.
An acid solubility test was made to determine the released calcium content from enamel into a 0.4 M acetate-sodium acetate buffer (pH 4.0) during three hours every thirty minutes.
In the experiments of fluoride mouth-rinsing, the fluoride acquisition by intact enamel was increased. Especially the surface layer of enamel contained greater amounts of fluoride, which increased with time. The distribution of fluoride was observed in the inner layer of enamel treated with fluoride mouth-rinsing solution. An acid solubility test proved that the acid resistance was increased 2-3 times more in the fluoride treated enamel than in the control.
