Immunological Response in the Dental Pulp After Caries Treatment
Objectives: This study investigated the responses of the immune system to carious lesions and how operative procedures influence the distribution of the immunocompetent cells.
Methods: We have examined 30 human teeth from patients at the age of 9 to 14 years. This study investigated the responses of the immune system under 3 different clinical conditions: shallow and deep cavities and treated caries. Teeth were extracted from various therapeutic reasons (mostly from orthodontic reason), 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 thickness and stained by the streptavidin-biotin complex immunoperoxidase method. Cells were identified immunohistochemically by using the following monoclonal antibodies: HLA-DR (for dendritic cells), CD45RO (for memory T lymphocytes), and CD20 (for B -lymphocytes).
Results: Initial pulpal response was characterized by a localized accumulation of HLA-DR antibody-positive cells in the pulp tissue beneath the caries lesion. In the pulp of progressed caries, a large number of HLA-DR-positive cells were observed with a marked increase of CD45 and CD20 positive cells. This might indicate the occurrence of antigen presentation locally in the pulp tissue which is very important for the immune response. However, six months after treatment, clusters consisting of HLA-DR-positive cells and CD45-positive T lymphocytes were recognized locally in the pulp tissue, regardless of cavity depth. CD20-positive B cells were seen only under the deeper cavities.
Conclusions: The results of this study demonstrated that dental pulps respond to cavity preparation and restoration, and that antigen presentation and cellular or humoral immune responses persist for many months, even after caries treatment.