Glial network responses to polymicrobial invasion of dentin

Abstract

Aim The aim of this study was to investigate the distribution patterns of glial networks disclosed by reactivity for glial fibrillary acidic protein (GFAP) and S100B in caries-free and carious human teeth. This was done In order to determine the assembly and collapse of glial networks in response to encroaching infection. Methods Fifteen caries-free and 37 adult human carious posterior teeth were studied. Immediately after extraction, teeth were cleaned and vertically split and the half with pulp fixed and prepared for resin or frozen sections. The sections were stained with toluidine blue and for immuno-fluorescence, with observation by confocal laser microscopy and analysis by ImageJ software. Results In Stage A lesions there was marked increase in glial networks in dental pulp tissue that extended beyond the zone of microbial invasion. This response was maintained in Stage B lesions. In advanced Stage C lesions these networks were degraded in the zone of invasion in association with failure to contain infection. Conclusion The late stage of dentinal caries was marked by collapse of these networks in the region adjacent to advancing bacteria. This behaviour is important for understanding and explaining the defensive response of the neurosensory peripheral dental pulp apparatus to infection.