Cell adhesion.

Before cells can adhere to a surface, the atoms forming the adhesive bonds must come to within 0.5 nanometers of each other. Distances of this order may not correspond to the averaged electron micrographic data. The events leading to close approach of parts of cells are discussed in terms of electrical parameters, with an emphasis on the surface heterogeneities of cellular adherends. The distinct phenomenon of cell detachment is not simply the reverse of cell adhesion, and must be measured by different techniques. The effects of various pathophysiologic factors on cell attachment and detachment is discussed, with illustrative examples of direct and indirect factors. These include regeneration, degeneration, metabolic inhibitors, endotoxin and antisera. It is concluded the stability of the union between cells and teeth represents a delicate balance between factors promoting contact and initial adhesions, factors strengthening the adhesive interphase and factors promoting separation.