sftd7 Download single image for 35mm slide. Download single PowerPoint screen.	Normally, equilibrium exists between mineral loss (demineralization) and mineral gain (remineralization). Demineralization occurs when acid lowers the pH at the tooth surface. This causes calcium, phosphate, and other minerals to diffuse out of the enamel and creates a subsurface lesion. (Photo: diagram of caries process)
sftd8 Download single image for 35mm slide. Download single PowerPoint screen.	(Photo: micrograph of an initial carious lesion. Note intact outer layer surface and carious lesion.)
sftd9 Download single image for 35mm slide. Download single PowerPoint screen.	Remineralization represents the opposite reaction. During remineralization, mineral is redeposited in the subsurface lesion. Fluoride, even in low concentrations, can enhance the remineralization of enamel and may actually result in a crystal structure that is more caries resistant. In this process of demineralization and remineralization, enamel caries can actually be repaired providing the outer surface layer of the enamel is still intact. Once the outer surface layer is lost, the potential for remineralization is also lost, and the tooth must be restored. (Photo: remineralized lesion. Note intact surface layer and remineralization area.)