Localization of fibronectin during dentinogenesis in rat incisor.

Fibronectin (FN) was localized in the dental pulp and predentine at different stages of dentinogenesis by indirect immunofluorescence. Fibronectin was present in the basement membrane between the inner enamel epithelium and the underlying dental mesenchyme and also in mantle predentine. Fibronectin was absent from predentine during further (circumpulpal) dentine formation, indicating that the FN molecule is not directly involved in mineralization. The findings emphasize the difference between the mantle and circumpulpal dentine formation. Fibronectin was localized in the odontoblast layer at the level where the cell processes leave the cell bodies and where the odontoblasts adhere to each other by junctional complexes.