A CONFOCAL LASER-SCANNING MICROSCOPIC STUDY OF THE IMMUNOFLUORESCENT LOCALIZATION OF FIBRONECTIN IN THE ODONTOBLAST LAYER OF HUMAN TEETH

The distribution of fibronectin in dental pulp was studied in developi ng and developed human teeth by indirect immunofluorescence using a co nfocal laser scanning microscope. In the apical region of developing t eeth, intense fluorescence was found along the basement membrane facin g the mesenchyme of Hertwig's epithelial sheath and first-formed (mant le) predentine. With further elongation of odontoblasts, fibronectin w as observed between the cells, appearing as corkscrew fibres passing f rom the pulp into predentine parallel to the long axis of the odontobl asts. In the coronal region of developing and developed teeth a simila r distribution of fibronectin was observed in the odontoblast layer. A t the border zone between odontoblasts and predentine the reaction was intense, but was weak in the predentine itself. In the calcified dent inal matrix it had disappeared completely, except for the area along t he dentinal tubules. The results demonstrate that fibronectin is prese nt in the odontoblast layer during all stages of dentinogenesis. Fibro nectin-positive fibrous structures between odontoblasts probably corre spond to von Korff fibres, and are closely related to odontoblast diff erentiation and dentinogenesis.