Root caries histopathology and chemistry

This paper reviews the histopathology of root surface caries, and the effect of fluoride on the root caries process. The root caries process may be defined as a dynamic equilibrium similar to enamel caries. The caries process produced acid demineralization in exposed root surfaces and resulted in a lesion body when viewed in the light microscope. A relatively intact surface layer was not always present unless root caries was observed. In the absence of fluoride, a significant surface layer was left devoid of mineral but with intact collagen. Fluoride helped to prevent lesion formation and produced radiodense banding within the lesions in in vitro models. Remineralization occurred on the remaining mineral and not on the collagen matrix devoid of mineral. The conversion of active to inactive root caries requires the formation of a mineralized layer and implies the loss of surface tissues and contour in the clinical situation.