Collagen sponge as a scaffold for tooth tissue engineering

Objective: The goal of this study is to develop a new technology for replacement teeth. Recently, an increasing number of elderly people suffer from the loss of teeth due to periodontitis or dental caries. Regeneration of tooth substitute, especially derived from the cell based on tissue engineering, is one of ideal therapies. It is reported that teeth could be regenerated by implanting dissociated odontogenic cells seeded onto a scaffold based on tissue engineering principles. However, the best scaffold for tissue-engineered tooth has not been determined. 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 mesenchyme from third lower molars of six-months-olds pigs were enzymatically separated, dissociated into single cells, and seeded heterogeneously onto a collagen sponge.To determine the capacity of collagen sponge to induce epithelial-mesenchymal interactions, ALP activity and cell growth in collagen-cell constructs were evaluated after 7-day culture. We then performed transplantation of the isolated tooth bud cells combined with the collagen sponge. Results: After 7 days, ALP activity exhibited a significant increase in the recombined epithelial cells and mesenchymal cells in collagen sponge compared with that in the collagen sponge seeded with epithelial or mesenchymal cells alone. In in vivo study, the regenerated tissue consisted of dentin and well differentiated pulp chamber at 15 weeks after implantation. At 20 weeks, enamel and cementum-like tissues were observed. All structure in tooth constitution can be observed in this technique, coincided with previous PGA experiments. However, the collagen sponge itself did not have a prominent advancement against the PGA scaffold in in vivo study. Conclusion: A tissue engineering approach utilizing porcine isolated tooth bud cells seeded on collagen sponge results in the successful tooth regeneration.