Materials and methods: Ten human healthy teeth were extracted for orthodontic or surgical purposes and processed for histological and immunocytochemical examination with the streptavidin-biotin-peroxidase method. Highly purified antibodies were used to reveal the distribution of intermediate filaments (vimentin, desmin, alpha-smooth muscle actin), histiocytic antigens (alpha-1-antitrypsin, lysozyme), neural and neural-crest-associated antigens (neuron-specific enolase, chromogranin-A, S-100, synaptophysin, glial fibrillary acidic protein, neurofilaments) in the adult pulp tissue.
Results: Vimentin immunostaining was strongly positive in the network of pulpal fibroblasts. Desmin and alpha-smooth muscle actin were present only in the vessel walls. Staining for alpha-1-antitrypsin and lysozyme reveals a number of macrophage-like cells in the central portion of the pulp. Macrophages were the most dominating immunocompetent cells. Negative immunostaining for chromogranin-A demonstrated the absence of neuroendocrine antigens in the adult dental pulp. Immunostaining for neuron-specific enolase, S-100 protein, synaptophysin, glial fibrillary acidic protein and neurofilaments were positive, with different intensity, in nerve fibres, but no pulp cell was found to be immunoreactive.
Conclusions: The conclusion is drawn that the lack of labelling of pulp cells by the neural associated antibodies could be due to differentiation processes during tissue development.