The release of carbonate during the dissolution of synthetic apatites and dental enamel

Abstract

Preferential dissolution of carbonate in synthetic carbonate apatite, powdered human dental enamel and human enamel platelets was studied by acid dissolution. The dissolution rates were determined at 37 °C, at pH 4.0, 5.0, 6.0 and 6.6, and for different stirring rates. The carbonate content of the partially dissolved samples was determined by infrared spectroscopy. Results indicate that preferential carbonate loss is particularly detectable at the following conditions: (a) small undersaturation; (b) weak stirring rate; (c) high carbonate content of the dissolved sample. The preferential loss was attributed to a superficial reprecipitation of DCPD or another phosphate complexe affecting particularly phosphate diffusion.