Mast cells of the human gingiva

Comparative histochemical studies with specific regard to the demonstration of mast cells were carried out on 21 different chronically inflamed marginal gingival specimens. For the demonstration of sulphated acid mucopolysaccharides two metachromatic stains were used-toluidine blue (pH 1.0) and acridine orange (pH0.5)-, as well as one orthochromatic stain- astra blue (pH 0.2–0.3). In addition the alcian blue-safranin sequence was employed to distinguish between weakly and strongly sulphated mucopolysaccharides. Trypsin-like esterase activity was demonstrated by the EACNAS-GBC technique. The metachromatic stains used stain mature mast cells specifically, while the non-metachromatic techniques stain immature mast cells as well. The chemical backgrounds for the different staining reactions are discussed. The chronically inflamed human gingivae were found to be rich in both mature and immature mast cells. The great majority of the immature mast cells were found within the pocket area of the connective tissue. Here, the number of mature mast cells was significantly smaller than in the oral area. The distribution of the different mast cell variants indicate a relation between mast cells and diffusible products from the gingival bacterial plaque.