White Spot Carious Lesions 2

Graphic representation of a block of enamel showing the surface and sub-surface enamel morphological changes in various stages of demineralization leading to white spot formation and finally to cavitation.

1. Intact block showing enamel surface and sub-surface.

2. Beginning of demineralization creates spaces in the enamel called pore spaces. Pores extend from the surface into the subsurface area. These are the initial signs of the white spot lesion creating the surface roughness and loss of shine..

3. As demineralization progresses, pore space increases and with remineralization the pore space decreases. As demineralization increases, the number of surface pores increase and the pore space size throughout the enamel also increases (ref).
As long as a relatively intact surface layer is present no bacterial invasion into the subsurface areas appears to occur

4. As the channels enlarge bacteria may invade the subsurface. It is somewhere during these stages of the demineralization process that the white spot lesion will lose its potential for remineralization.

May be due to:
1. Destruction of sufficient amount of the enamel matrix .
2. Alterations in the acid diffusion pattern into the subsurface resulting in lower pH and its mainteneance for longer time periods.
3. Sufficient amount bacterial invasion into the subsurface.
Fluoride, because of its ability to penetrate enamel, is effective in controlling the mutans strep that may invaded the subsurface area or body of the lesion. Chlorhexidine does not penetrate well into the body of the lesion and thus will not reach bacteria within the lesion.

5. In the final stage, the carious process has progressed to the point where sufficient amount of enamel matrix has been lost. This results in the inward collapse of the remaining surface layer. At this stage restorative procedures are indicated.

(Silverstone LM, Structural alterations of human dental enamel during incipient carious lesion development. In: Rowe NH, ed. Proceeding of Symposium on Incipient Caries of Enamel. U of Michigan, School of Dentistry, 1977:3-49. )