Ecological Hypothesis of Dentin and Root Caries

Abstract

Recent advances regarding the caries process indicate that ecological phenomena induced by bacterial acid production tilt the de- and remineralization balance of the dental hard tissues towards demineralization through bacterial acid-induced adaptation and selection within the microbiota - from the dynamic stability stage to the aciduric stage via the acidogenic stage [Takahashi and Nyvad, 2008]. Dentin and root caries can also be partly explained by this hypothesis; however, the fact that these tissues contain a considerable amount of organic material suggests that protein degradation is involved in caries formation. In this review, we compiled relevant histological, biochemical, and microbiological information about dentin/root caries and refined the hypothesis by adding degradation of the organic matrix (the proteolytic stage) to the abovementioned stages. Bacterial acidification not only induces demineralization and exposure of the organic matrix in dentin/root surfaces but also activation of dentin-embedded and salivary matrix metalloproteinases and cathepsins. These phenomena initiate degradation of the demineralized organic matrix in dentin/root surfaces. While a bacterial involvement has never been confirmed in the initial degradation of organic material, the detection of proteolytic/amino acid-degrading bacteria and bacterial metabolites in dentin and root caries suggests a bacterial digestion and metabolism of partly degraded matrix. Moreover, bacterial metabolites might induce pulpitis as an inflammatory/immunomodulatory factor. Root and dentin surfaces are always at risk of becoming demineralized in the oral cavity, and exposed organic materials can be degraded by host-derived proteases contained in saliva and dentin itself. New approaches to the prevention and treatment of root/dentin caries are required.

Zinc Inhibits Collagenolysis by Cathepsin K and Matrix Metalloproteinases in Demineralized Dentin Matrix

“…Recent advances in understanding the caries process in dentin and root surfaces indicate that, in addition to microbial acid-induced adaptation and demineralization [Chaussain-Miller et al, 2016;Takahashi and Nyvad, 2016], the degradation of dentin organic matrix (DOM) by host-derived endogenous proteases might play a significant role in the progression of the caries lesion. Dentin contains endogenous proteases including matrix metalloproteinases (MMPs) -2, -8, and -9 [Mazzoni et al, 2012[Mazzoni et al, , 2013 Tjäderhane et al, 2013a, b] as well as cysteine cathepsins (CCs), primarily cathepsin K [Tersariol et al, 2010;Nascimento et al, 2011;Vidal et al, 2014].…”

Salivary sCD14 as a potential biomarker of dental caries activity in adults

“…Dental caries is the localised destruction of susceptible dental hard tissue caused by complex interactions between cariogenic bacteria, fermentable carbohydrates, and host factors (1,2). Common virulence factors among the Gramnegative bacteria are endotoxins (whose biologically active components are lipopolysaccharides, LPS) and among the Gram-positive bacteria it is the lipoteichoic acid (3,4).…”

Diagnostic accuracy of a charge-coupled device and a photostimulable phosphor plate in detection of non-cavitated proximal caries

“…22 In addition, enamel remineralization can arrest carious lesion in its outer shell, however, dentin has already lost its collagen matrix. 23 Therefore, in the present study, a small number of non-cavitated carious lesions were detected but according to histology they were deeper. Considering the previously mentioned studies, it can be argued that despite the advances in technology that allow for better viewing of digital images, no greater accuracy in detecting carious lesions between CCD and PSP has been shown.…”