Bacterial invasion of gingiva in advanced periodontitis in humans.

Using scanning electron microscopy, bacteria were found invading the epithelial wall of deep periodontal pockets in five out of eight cases. In one case, bacteria had reached the connective tissue. The following bacterial morphotypes were identified: cocci, short rods, filaments and spirochetes. A corncob-like formation with a few scattered spirochetes was found in one case between the junctional epithelial cells. Numerous cocci, rods and filaments were found in intercellular spaces of the epithelium in the lateral wall of the pocket and accumulating on the epithelial side of the basement lamina. Bacterial invasion of gingival tissue may have important pathogenic and therapeutic implications.