Collagen-sponge-based tissue engineering of tooth

Objective: It has been reported that teeth could be regenerated by implanting dissociated odontogenic cells seeded onto a scaffold in vivo based on tissue engineering principles. However, it is not clear what the best scaffold for tissue-engineered tooth is. To address this issue, here we report our first attempt at transplantation of tooth bud heterogeneous cells and collagen scaffold into an immunocompromised animal. Methods: Enamel organ and dental mesenchymes from third lower molars from six olds pigs were enzymatically separated. Each tissue was further dissociated into single cells, and the isolated heterogeneous cells were then seeded onto a collagen sponge.Collagen-cell constructs were cultured to evaluate the ALP activity followed by 7-day culture. In in vivo study, we performed the transplantation in combination with each type of isolated cells and collagen sponges, and the implants were examined by histology and immunohistochemistry. Results: After 7 days, ALP activity exhibited a significant increase in the recombined epithelial cells and mesenchymal cells in collagen sponge compared with that of single epithelial cells or mesenchymal cells alone seeded on the collagen sponge. Based on this result, collagen sponge has a capacity to induce an epithelial-mesenchymal interaction. The regenerated tissue consisted of dentin and well-differentiated pulp chamber 20 weeks after implantation. By 25 weeks after implantation, enamel and cementum-like tissue were observed in the constructs. On the other hand, when the epithelial cells or mesenchymal cells alone were transplanted into nude rats, there was no dentinal tissue formation. Recombination of epithelial and mesenchymal cells served induces the interaction of epithelium and mesenchyme and possess to regenerate the tooth structure. Conclusion: A tissue engineering approach to tooth replacement utilizing porcine isolated tooth bud cells seeded on collagen sponge resulted in the successful tooth regeneration.