Cell proliferation in teeth reconstructed from dispersed cells of embryonic tooth germs in a three-dimensional scaffold

Tissue engineering can now reproduce tooth from postnatal tooth cells. However, crown formation is not accurately reconstituted, even when the complex structure of the enamel dentin is reproduced. Here, we showed that a tissue-engineered (TE) tooth, exhibiting morphogenesis according to regular crown-cusp pattern formation, was produced by embryonic tooth germ cells in a three-dimensional scaffold. Heterogeneous cells dissociated from embryonic day 14 (E14) mice tooth germs were seeded on a scaffold and implanted under a kidney capsule in adult mice. The developmental process of the implants was examined for up to 14 d. At 5 d, the cells had formed initial tooth germ, followed by enamel-covered dentin tissue formed symmetrically. To study the developmental process, we examined the growth pattern using 5-bromo-2'-deoxyuridine (BrdU)-labeling analysis. The initial cell-proliferation patterns of the TE teeth were similar to that at the cap and early bell stages in natural teeth. This was particularly true in the cervical loop, which showed a similar distribution pattern of BrdU-positive cells in TE- and natural teeth. These results suggested that even when embryonic tooth germs are dissociated, the single cells can reconstitute tooth, and that enamel organ morphogenesis proceeds as in natural teeth.