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Objective To evaluate the presence of cytolytic T lymphocytes (CD8+), memory T cells (CD45RO+), helper T lymphocytes (CD4+), and mast cells in pulps from healthy and carious human teeth. Study design The teeth were separated into groups: I = unerupted; II = partially erupted, without caries; III = erupted, without caries; IV = erupted with shallow dentine caries; and V = teeth with pulp polyps. The immunoperoxidase staining procedure was used to detect CD8, CD45RO, CD4, and tryptase (mast cell marker) antigens. The number of each cell type was obtained by counting the number of cells per mm2. Results Mast cells were only present in pulp polyps. Pulps from carious teeth contained more CD4+ and CD8+cells than from noncarious teeth. There was a significant decrease in the number of lymphocytes in pulp polyps in comparison to the other groups. Conclusions Mast cells probably do not contribute to the early vascular or specific immune responses in the initial dental pulp pathosis, although they may be involved in a chronic phase of pulp inflammation such as pulp polyps. On the other hand, CD4+ and CD8+T cells participate mainly in initial phenomena of the immune response to incipient caries and seem not to substantially contribute to the response in pulp polyps.

Cells other than macrophages and lymphocytes have recently been shown capable of producing cytokines and mediators. Among these are mast cells, a cell population now recognized for its immunoregulatory properties. Little is known about the complex interactions between cells, cytokines, and other inflammatory elements in periapical lesions. The objective of this investigation was to determine the immunohistochemical pattern of expression of mast cells tryptase in periapical lesions based on study of 20 apical granulomas and 20 periapical cysts. Microscopic analysis revealed mast cells to be present in greater numbers in periapical cysts than in apical granulomas, and in cysts were more numerous in regions of active inflammation. Mast cells tended to be more common in the peripheral regions of both periapical lesions, and were often found in close proximity to lymphocytes. These findings lead us to propose a functional relationship between these two cell populations that may facilitate elicitation of an immune response contributory to the pathogenesis of periapical lesions.

In the periapex, the interaction among inflammatory cells and microorganisms and their products results both in specific and nonspecific immune responses. Many studies have reported quantitative analysis of the immunocompetent cells in periapical lesions, but the exact ratio of these cells in cysts and granulomas remains unknown. In the present study, we undertook a quantitative analysis of CD68 + cells and CD8 + T cells in human periapical granulomas and cysts. Immunoperoxidase staining revealed that CD68 + cells were present in both lesions, with no statistically significant difference, mainly distributed in the inner portion of the lesion, where the inflammation site is more active. On the other hand, CD8 + lymphocytes were more numerous in cysts. Thus, it appears that CD8 + T cells may play a more important role in a later phase of periapical lesion progression, probably exerting regulatory or cytotoxic functions in cellular immune response, which may lead to the stabilization of these lesions. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;92:221-7)

The authors describe a clinical case of a palato-gingival groove on a maxillary central incisor with associated localized periodontal disease and pulp necrosis. The general clinician's initial diagnosis was incorrect; this led to incomplete treatment and subsequent loss of the tooth. Recognition of the palato-gingival groove is critical, especially because of its diagnostic complexity and the problems that may arise if it is not properly interpreted and treated.