Assessment of Root Caries Lesion Activity and Its Histopathological Features

Despite certain similarities in the etiology of root caries (RC) and coronal caries, there are notable differences in their histology, namely with regard to the demineralization process, which should be taken into consideration when assessing lesion activity. In this chapter, we present the histological changes to the dentin and pulp, occurring physiologically or in response to caries lesions. We focus on the histological features specific to RC lesions, discussing the assessment of lesion activity. The physiological changes occurring to the dentin and pulp are the formation of secondary dentin and the sclerosis of dentin tubules, while tertiary dentin is formed during pathologic stimuli from caries lesions. Already in the early stages of active RC, the lesions seem softer, and bacteria are easily found within the dentin tubules. Inactive lesions, on the contrary, are characterized by fully remineralized tissue, with irregular mineral precipitation and containing ghost cells of microorganisms. Lesion activity is determined by observing their tactile sensation and their position with respect to the gingival margin.