ADSORPTION OF 2 POLYPHOSPHONATES ON HYDROXYAPATITE AND THEIR INFLUENCE ON THE ACID SOLUBILITY OF WHOLE BOVINE ENAMEL

The preparation and characterization of two poly phosphonates is described and the adsorption mechanism of a saturated and an unsaturated polyphosphonate on hydroxyapatite investigated. During adsorption phosphate ions are released in solution. It was found that equal amounts of the two adsorbed polyphosphonates resulted in the same amount of released phosphate. The difference in the amount of the two adsorbed polymeric materials on the hydroxyapatite surface is explained by the greater density of negative charges along the unsaturated polyphosphonate chain. After pretreatment of slabs of whole bovine enamel with aqueous solutions of the polyphosphonates, solubility experiments were carried out in order to study the carries-reducing effect of these polyphosphonates on bovine enamel. Specific differences were observed between the two polyphosphonate solutions at the same pH. A variation in the pH of these solutions was found to have a considerable effect on the solubility of the enamel. Solubility reductions of up to 70 per cent were observed. © 1979.