Specificities of Caries on Root Surface.

Variations in organic and inorganic composition and morphology may determine different susceptibilities of root surfaces to caries. Subsequent to gingival recession, root surfaces become exposed and those areas where Sharpey's fibers system was once inserted into the cementum are converted into canals for microbial penetration. In the presence of a cariogenic root biofilm, the fermentable carbohydrate from diet is converted into organic acid, and the root caries lesion is initiated in the exposed root site. We will revisit here the structural, biochemical, and histopathological specificities of root caries. Likewise enamel, the root surface exchange minerals with oral fluids, resulting in a subsuperficial root caries lesion. After mineral loss, the collagen is degraded and the lesion progresses. The specificities regarding the critical pH for demineralization of root hard tissues, the influence of cementum loss for lesion progression, and the organic matrix degradation will be discussed in this chapter. The tissue-related phenomena would create lesion with a unique histopathology. Active and arrested root carious lesions will be discussed through the gradual development from the cementum to dentin.