Immunopathological Mechanisms of Pulpal Protection and Destruction

Methods: 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). 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.

Results: In normal pulp only antigen-presenting cells and rarely T cells are present. Early pulpal response to bacterial diffusion of bacterial products through dentinal tubules elicit the influx of macrophages and T lymphocytes. As the infection is coming closer to the pulp, the response assumes a typical mixed character, consisting of T cells and B cells. T lymphocyte-mediated immune response has central role in the initiation of pulpal specific immunity, and in the advanced phase B-lineage cells further the humoral immunoresponse.

Conclusions: This study suggest that immune mechanisms play an important role in pulpal infection resistance. Cells involved in the immunopathologic mechanism may have a crucial role in the initiation of pulpal defence against carious attack. Invasion of the pulp tissue by bacteria caused dense accumulation of the immunocompetent cells with the predominance of B cells.