Tooth enamel demineralization, triggered by an increase in the acidity of bacterial plaque, is the initiation of the caries process.1 In any discussion of the caries process, particular attention is paid to the enamel - the hard, outermost layer - because it is the primary contact with cariogenic bacteria, and where the demineralization process that can lead to caries first begins. It is also the only tissue of the tooth that does not have the ability to grow or repair itself after maturation, making it even more crucial that its demineralization is prevented.2 Caries can also develop in dentin, the hard layer under the enamel, so understanding the chemical composition of this layer, and how it is affected by demineralization, is also important.

The process of remineralization - the replacement of lost minerals in hard dental tissues - can halt, slow down, and, in some cases, reverse the caries process.1 Saliva and fluoride are two key players in remineralization: Healthy saliva contains ample amounts of the calcium and phosphate ions that can replenish lost minerals in hard tooth structure, and fluoride can be incorporated into the tooth structure to strengthen it.1,3 For caries prevention, factors in the oral cavity must be highly favorable for remineralization to occur, so that this process can be effective. If the environment is more favorable for demineralization, the remineralization process may have little or no influence, or not occur at all; and caries will develop.