Effect of Hydroxyapatite on Reaction of Dicalcium Phosphate Dihydrate DCPD) and Fluoride Ion

DCPD, dicalcium phosphate dihydrate (CaHPO4•2H2O) reacts with fluoride ion in an aqueous solution, and forms fluorapatite (FAp, Ca10(PO4)6F2). In previous study, we have found that DCPD does not react with fluoride ion directly, but show few hours of induction period by reaction with fluoride. In this study, effect of hydroxyapatite (HA, Ca10(PO4)6(OH)2) on the reactivity of DCPD with fluoride ion was investigated. By mixing HA with DCPD, it was appeared that the induction period of the reaction was shortened. Morphology of the obtained FAp was similar to HA paricles. We carried on coating of HA on the DCPD particle by soaking DCPD in simulated body fluid (SBF, Kokubo Solution). By coating HA on DCPD particles, particle morphology of the obtained FAp was consistency to the DCPD particles. These results suggest that the shape and particle size of FAp after reaction of DCPD is controllable by DCPD particle as template, and coating with HA.