| Autor: |
Thomann, J.M., Voegel, J.C., Gramain, Ph. |
| Zdroj: |
Journal of Colloid and Interface Science; May 1993, Vol. 157 Issue: 2 p369-374, 6p |
| Abstrakt: |
A model for the dissolution of calcium hydroxyapatite (HAP) is proposed using the current theory of ionic transport through a permselective membrane. In order to describe the experimentally observed self-inhibiting dissolution mechanism, the model includes an interfacial ionic layer formed at the apatite surface by the adsorption of calcium ions. It provides a quantitative explanation for the phenomenological rate reducing factor kintroduced previously. In particular, the analysis shows that the experimental dependence of kwith pH is well explained by the difference of permeability of the layer to HPO2-4and H2PO-4ions resulting from HAP dissolution. The values of the calcium adsorption parameters estimated from the comparison of the experiments with the model are in agreement with adsorption on phosphate and/or hydroxyl sites exposed on the apatite surface. The proposed theory may constitute a new approach to understanding the role of inhibitors of HAP dissolution and of the carious process. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
