Dentinogenic activity of allogenic plasma fibronectin on dog dental pulp.

The response of ectomesenchymal cells of dog dental pulp to implantation of Millipore filters supplemented with bovine plasma fibronectin was evaluated after observation periods of one or four weeks. Two concentrations of plasma fibronectin were used (0.2 and 1 mg/mL). Experiments also included implants treated with control solutions (PBS or 1 mg/mL of dog albumin). Formation of a layer of elongated, polarized cells was demonstrated in direct contact with the implants treated with 1 mg/mL of plasma fibronectin solution, after one week post-operatively. Microfilamentous organization and orientation of rough endoplasmic reticulum was observed mainly in the supranuclear zone of the polarized cells. Implants treated with the same solution were consistently surrounded by a thick layer of dentinal matrix after four weeks of their exposure to pulp sites. Implants treated with control solutions or with the low concentration of fibronectin never showed any sign of cell polarization and matrix synthesis. These data provide evidence that the pulp cells can express their odontoblastic phenotype in response to a surface containing concentrated fibronectin (even allogenic), without the need of other molecules as exogenous inductive factors.