Is a missing tooth ruining your smile? Here’s an unlikely recipe for cooking up a replacement – with the help of a mouse and some of your own urine.

Duanqing Pei from the Chinese Academy of Sciences in Guangzhou and colleagues took stem cells from human urine and used them to grow teeth inside mouse kidneys. The stem cells were transformed into dental epithelial tissue, mixed with mouse connective tissue cells and grown for two days before being implanted under the outer layer of the mouse’s kidney. There the human stem cells developed into enamel, while the rest of each tooth was formed from mouse cells.

Pei claims that a method for using mice to grow teeth containing only human cells “could be easily designed”.

The work is promising but figuring out what governs the size and shape of different teeth is going to be a big problem in making it useful, says Mark Bartold from the University of Adelaide in Australia, who works on regenerative dental medicine. “It doesn’t take a genius to figure out there’s a big difference between an incisor and a molar tooth,” he says. “That’s going to be very tricky, because we don’t really fully understand what’s involved in that development.”


Pei agrees, but says having natural replacement teeth available to fit into the right slots in the mouth may be of benefit. He also notes that the teeth his team grew were a bit softer than real teeth, which might be because they were not being used as they grew. “We do not have the physical stimulations found in the mouth,” he says.

Bartold says there are already very good titanium dental implants available today, but the work is still useful as it could help us understand the development of teeth, which could in turn boost other areas of regenerative medicine. “The tooth, believe it or not, for decades has been used as a wonderful tool for understanding development biology,” he says.

Pei and colleagues agree, writing that the tooth represents “one of the best models in organogensis”.

But why did they grow the teeth from cells in urine? “This is the most convenient source,” says Pei.

Journal reference: Cell Regeneration, in press

Correction: Details of how the stem cells were used have been clarified since this article was first published on 30 July.