Effect of Fluoride on the Ion-association of Calcium Phosphate and Crystallization of Hydroxyapatite

Abstract

Using a titration setup to accurately control the reaction conditions and in situ monitor the reaction, we showed that fluoride exhibited negligible effects on the ion association process of calcium and phosphate and the formation of ACP nanospheres in a buffer solution with constant ionic strength. However, the stability of ACP increased with increasing fluoride concentration, which was ascribed to the inhibitory effect of fluoride on the aggregation of ACP nanospheres and the nucleation of nanocrystals on the surface of ACP nanospheres. Furthermore, fluoride could inhibit the lateral growth of HAP nanosheets and promote the formation of rod-like crystals. These results further improve our understanding of the crystallization pathway of HAP crystals and the regulatory effects of fluoride.

Keywords

crystallization / amorphous calcium phosphate / hydroxyapatite / fluoride

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