Cellular Changes at the Dentin-pulp Interface During Caries Progression

Objectives: The dentin-pulp interface (DPI) in human teeth is a highly organized multicellular system playing crucial roles in defense, repair and regeneration in response to pathogen invasion during caries progression. The aim of this study was to establish the main changes affecting the organization of cellular DPI components in response to moderate and severe caries.
Methods: Using immunohistochemical and confocal microscopy, a comparative analysis of nerve terminal organization, Schwann cell network, immunocompetent cells and vascular components was performed. Healthy and carious human permanent molars were assayed with immunohistochemical procedures using markers for neural components (NF, TUBB3, S100, GFAP, p75NTR), immunocompetent cells (HLA-DR, CD45, CD15) and vascular components (vWF, CD31, CD34, CD105, CD146, αSMA). Images from immunolabeling were acquired with confocal microscopy and quantitatively analyzed.
Results: In teeth with moderate caries a progressive sprouting of nerve endings and activation of glial cells associated with affected caries domains was observed at the DPI. A relevant infiltration of dendritic cells and scarce presence of CD15+ was determined. Early microvascular changes adjacent to injured locations were characterized using double labeling for vWF and CD105. CD146 immunoreactivity was increased in perivascular and glial cells in the proximity of carious lesions. In teeth with severe caries, an important infiltration of inflammatory cells in relationship with angiogenesis was determined.
Conclusions: This first approach revealed a sequential progression of concerted cellular changes involving the nervous, immune and vascular systems at the DPI from moderate to severe caries conditions. This study helps to understand the crucial response capacities of nerves, glia and immune-vascular components to coordinate defense, repair and regenerative events at the DPI. (Supported by Fondecyt 1141281- Conicyt/Chile)