IMMUNOHISTOCHEMISTRY OF THE INTERCELLULAR MATRIX COMPONENTS AND THE EPITHELIOMESENCHYMAL JUNCTION OF THE HUMAN TOOTH GERM

The immunohistochemical localization of heparan sulphate, collagen typ e I, III and IV, laminin, tenascin, plasma- and cellular fibronectin w as studied in tooth germs from human fetuses. The lamina basalis amelo blastica or membrana preformativa, which separates the pre-ameloblasts from the pre-dentin and dentin, contained heparan sulphate, collagen type IV, laminin and fibronectin. Enamel reacted with antifibronectin, but the reaction varied depending on the type of fibronectin and the source of antibody. In early pre-dentin, collagen type I, laminin, ten ascin and fibronectin were present. In late pre-dentin and dentin coll agen type I was found in intertubular dentin and in the zone between e namel and dentin. The close relationship between collagen type I in de ntin and fibronectin in immature enamel is interesting, as it may cont ribute to the stabilization of the amelodentinal interface. In dental pulp, collagen type IV and laminin were found in the endothelial basem ent membranes. Collagen type I and III, tenascin and fibronectin were localized to the mesenchymal intercellular matrix. The results of this study have supported the assumption that the lamina basalis ameloblas tica is a basement membrane, and have lead to the suggestion that amel oblasts are producers of fibronectin or a fibronectin-like substance.