Mast cells of the human gingiva

One-side gingivitis was induced in 21 individuals by local abolition of tooth cleansing for 15–17 days. Adjoining sections of biopsies from the non-cleansing side as well as from the control side with good tooth cleansing were stained with toluidine blue (pH 1.0), acridine orange (pH 0.5), astra blue (pH 0.2—0.3), alcian blue-safranin and the EACNAS-GBC technique in order to demonstrate mast cells specifically. The clinically normal gingiva was found to be rich in mast cells. In the inflamed tissue, the number was increased, especially in the pocket area of the connective tissue. The difference was due to an increase of both mature and, particularly, of immature mast cells. In those cases, where the inflammatory infiltrates were heavy, however, the number of mast cells was reduced in the area of cellular infiltration. The results indicate that products from the bacterial plaque at the gingival margin may directly or indirectly induce proliferation of mast cells in the adjacent connective tissue. Above a certain degree of stress, however the mast cells may respond by degranulation and release their active substances, which by contributing to the inflammatory reaction may enhance the local resistance.