August 3, 2009—Denture wearers take note: Science is one step closer to growing replacement teeth "from seed."
Researchers at the Tokyo University of Science created a "tooth germ" from mouse stem cells, implanted the 500-micrometer (0.02-inch) germ inside a mouse's tooth socket, and waited.
A month later, a new tooth erupted from the gum. The stem cell tooth was as hard and sensitive as a natural tooth, though the new tooth glowed green in ultraviolet light (pictured).
The team had attached green fluorescent protein to the tooth germ to better track the genes that were activated as the tooth grew—an increasingly common practice in genetic experiments.
The researchers used a method they had developed two years ago to create the tooth germs. In 2007 they had grown "primitive" teeth inside mouse bellies before transferring the teeth to jaws.
The new report, though, documents the first known fully functional bioengineered tooth.
It's a significant finding, said Yasuhiro Ikeda, a stem cell expert at the Mayo Clinic in Minnesota. Though scientists have known how to grow parts of organs from stem cells for years, "making everything from scratch like they did is still very challenging," said Ikeda, who was not involved in the new study.
This research, study co-author Takashi Tsuji said via email, is "expected to evolve into a wide variety of organ-regenerative technologies for liver, kidneys, and other organs."
Still, the Mayo Clinic's Ikeda cautions, "each organ is different, so it may take a long time before we can actually use this system in a clinic."
Findings to be published tomorrow in the journal Proceedings of the National Academy of Sciences.