Immunopathological Mechanisms Of Pulpal Protection

In order to investigate the immunopathology of the dental pulp as a sequel of caries, we have studied the distribution of immunocompetent and antigen-presenting cells in association with the development of the carious lesion.

Method:

In this study we have analysed 150 teeth with different stages of progression of the carious lesion. The condition of the pulp was classified into five groups according to the progression of the carious lesions from stages S0 (non-carious teeth) to S4 (exposed pulp). Teeth were extracted and immediately cut longitudinally; pulp tissue was extirpated and fixed in formalin for 24 hours at 4 °C. The specimens were embedded in paraffin, according to standardized laboratory procedure. Sections were cut at 5 μm thicknesses and stained by the streptavidin - biotin complex immunoperoxidase method. Cells were identified immunohistochemically by using the following monoclonal antibodies: CD3 for T lymphocytes, CD20 for B lymphocytes, HLA-DR for dendritic cells and CD68 for macrophages.

Result:

The immune response in the unaffected pulp is linked with the presence of antigen-presenting cells (pulp dendritic cells and macrophages) and rare T lymphocytes. The number of T lymphocytes showed an increase in teeth with shallow dentinal caries, while B-lymphocytes increased only in teeth with deep caries. A substantial change in the infiltration of immunocompetent and antigen-presenting cells occurred between S2 and S3, with a remarkable increase in the number of B-lymphocytes.

Conclusion:

These study suggest that immune mechanisms play important role in pulpal infection resistance.

T-lymphocyte-mediated immune response has central role in the initiation of pulpal specific immunity

Invasion of the pulp tissue by bacteria caused dense accumulation of the immunocompetent cells with the predominance of B cells.