The epithelial surface of deep periodontal pockets has been described using scanning electron microscopy. The presence of microtopographically distinct areas suggests that the pocket wall is constantly changing as a result of the interaction between the host and the epithelial- and pocket-associated bacteria. Seven topographical areas- were described: relative quiescence, bacterial accumulation, emergence of leukocytes, leukocyte-bacterial interaction, epithelial desquamation, hemorrhage, and ulceration.