Researchers in Japan exploring ways to regenerate 3-dimensional organs grew new teeth in mice by implanting bioengineered tissue into the animals' jaws (Ikeda E et al. Proc Natl Acad Sci U S A. 2009;106:13475-13480).
Studies indicate that teeth, like most organs, arise from organ-specific embryonic tissue, or germs, through interactions between epithelial and mesenchymal cells. The researchers isolated epithelial and mesenchymal cells from molar tooth germs from mouse embryos, recombined them, and grew the resulting bioengineered germs in culture for 5 to 7 days. After transplanting the germs into the jaws of adult mice in the site where a molar had previously been extracted, new and fully functional teeth grew in place in 7 weeks.
Stephenson J. Toothsome Achievement. JAMA. 2009;302(11):1161. doi:10.1001/jama.2009.1336