Tissue engineering in endodontics.

The key elements of the regeneration of dentine-pulp complex are stem cells, morphogens and a scaffold of extracellular matrix. The pulp stem cells have the potential to differentiate into odontoblasts in response to bone morphogenetic proteins (BMPs). However, the use of BMPs in vivo has been restrained by lack of a suitable scaffold. Therefore, two alternative approaches, in vivo and ex vivo gene therapy were performed. Bmp I I/Gdf I I gene was directly transferred into amputated pulp by sonoporation and the reparative dentine formation was stimulated in vivo. However, there should be enough responsive stem cells in the pulp. Therefore, the isolated progenitor stem cells from pulp were transfected with Bmp I I/Gdf I I by electroporation and implanted onto the amputated pulp. This ex vivo gene therapy stimulated reparative dentine formation more optimally and rapidly compared with the in vivo gene therapy. These results suggest the possible clinical use of gene therapy of BMPs for endodontics.