[Physiology of the gingivo-dental sulcus]

The gingival sulcus is formed by the space between the sulcular epithelium, the junctional epithelium, and the wall of the tooth. The functioning of its different parts is important in the early changes taking place when marginal plaque is accumulating. The cellular turnover of the junctional epithelium is very high, which could explain its high healing potential. The intercellular spaces are wider in the junctional epithelium, when compared to those of the sulcular or oral epithelia. Polymorphonuclear leucocytes can migrate through these spaces, attracted toward the sulcus by chemotactic substances. Numerous substances have been shown to permeate the junctional epithelium, both toward the sulcus and from the sulcus within the connective tissue. The sulcus is normally sterile and will tend to eliminate any foreign particle. Leucocytes and desquamated epithelial cells will also tend to leave the gingival sulcus and will be found in saliva. Various instruments, such as paper or celluloid strips of platinum loops, can be used to collect the content of the gingival sulcus. Quantitative investigations can be performed by analyzing crevicular fluid or the products of washings of the marginal gingiva.