Abstract
The purpose of this study was to investigate the effects of 7 days of washing on fluoride and titanium uptake, glaze formation and acid solubility. Specimens of human enamel were treated for 60 minutes with solutions of (NH4) 2TiF6 (0.9% of Fluorine, pH 3.4) or APF as control, followed by 7 days of washing with distilled water. These specimens were investigated for fluoride and titanium uptake by means of electron probe X-ray microanalysis and observations of their surface structure were made by scanning electron microscopy. Some specimens were etched for 15 seconds with 0.5 M HCIO4 to examine their acid solubility and were then observed by SEM. The calcium released from the enamel surface into distilled water during every 24hr period was determined by means of atomic absorption spectrophotometry.
In the electron probe X-ray microanalysis, fluoride and titanium in the enamel surface layer remained even after 7 days of washing, but the CaF2 formed on the enamel surface in APF-treated enamel was washed away. The glaze formation on enamel surfaces caused by the effect of titanium showed a strong resistance to washing and acid etching. Calcium content in distilled water released from enamel surface treated with ammonium titanium fluoride was lower than in the control group.
Therefore, it appears that the amorphous coating on titanium fluoride-treated enamel surface known as “glaze” is very resitant to washing and acid etching, and that the permanently bound fluoride and titanium in the enamel may contribute to the acquisition of caries resistance in human enamel.
