Characterization of the human junctional epithelial cells directly attached to the tooth (DAT cells) in periodontal disease.

This study examined the directly attached cells (DAT cells) of the human junctional epithelium from teeth extracted for advanced periodontal disease. The monolayer nature of the DAT cells remaining on the tooth surface after extraction offers a unique opportunity to study their morphology and activity in situ. We collected DAT cells and examined them by transmission electron microscopy and by autoradiography of cells labeled with 3H-thymidine. Our morphological results suggest that degenerative changes associated with pocket formation affect individual cells rather than regions of the DAT cell population at one time. The epithelial attachment apparatus (EAA) appeared to be the most resistant structure persisting on the tooth surface during the degeneration of the individual DAT cells. The new technique developed for two-dimensional observation of the sheet of DAT cells labeled in situ on the tooth surface in culture showed that the attached cells, even in periodontal disease, exhibit proliferative ability, suggesting a regenerative role for the DAT cells.