IMMUNOELECTRONMICROSCOPIC STUDY OF THE LOCALIZATION OF FIBRONECTIN INTHE ODONTOBLAST LAYER OF HUMAN TEETH

Indirect immunofluorescence-based studies have shown similarities in t he distribution patterns of fibronectin-positive fibrous structures an d so-called von Korff fibres. The aim of the present study was to anal yse the reactivity of fibronectin in the odontoblast layer of fully de veloped human teeth by means of immunoelectron microscopy. Between the odontoblasts, discrete and undulatory fibrillar fascicles with peroxi dase labelling were observed. They seemed to be in contact with odonto blasts in some areas, while in others they appeared to be intervening between two neighbouring odontoblasts. Higher magnifications of the fi brillar material demonstrated axial periodic staining of about 70 nm. Peroxidase reaction of fibronectin was also recognized along the cell membrane of odontoblasts facing predentine. The fibronectin in fibrill ar fascicles observed between odontoblasts would be held in place by t he direct molecular interaction with collagen fibrils and contribute t o the pulpward migration of these cells and maintenance of their speci fic morphology. At the distal end of odontoblasts, a tight seal would be maintained by means of odontoblast-fibronectin adhesion.