IMMUNOHISTOCHEMICAL STUDY ON THE IMMUNOCOMPETENT CELLS OF THE PULP IN HUMAN NONCARIOUS AND CARIOUS TEETH

The condition of the pulp tissue was classified into seven groups according to the depth of carious lesions from stage (S) 0 (non-carious teeth) to S6 (exposed pulp). A substantial change in the infiltration of immunocompetent cells occurred between S3 and S4; all types were markedly increased in S4 as compared to S3, with a remarkable increase in the number of helper T lymphocytes, B-lineage cells, neutrophils and macrophages. Therefore, the pulpal immune reaction to carious stimuli could be classified into early (S1-S3) and advanced phases (S4-S6). In the early phase a cellular immunoresponse would be induced by T-lineage cells, and in the advanced phase the humoral immunoresponse is furthered by B-lineage cells concomitant with the destruction of pulp tissue by proteolytic enzymes released from infiltrating neutrophils and macrophages. Human dental pulp is thus equipped with a functional immune response-that is sufficient as a biodefensive mechanism. Dental caries should be treated before S4.