Figure 3.

Diagrammatic summary of how hydroxyapatite functions to reduce the risk of caries

A) HAP particles penetrate enamel defects on the surface and below the surface to adhere to existing enamel structure. B) The ions produced as a result of biofilm acid dissolution of some HAP particles also contribute to the remineralization of enamel as it repairs after the acid attack is over. Some of the acid is buffered by HAP. In addition, those ions deposited in biofilm contribute to the rebuilding of tooth structure. C) HAP particles have been shown to bind to biofilm bacteria, inhibit their activity, and act as an abrasive to prevent biofilm accumulation. All 3 mechanisms serve to reduce the risk of caries progression in the dentition.