Sometimes, good oral hygiene just isn't enough to keep your mouth full of pearly whites perfectly intact. That's where science comes in (we'd hope). But the newest foray into fabricating teeth for when our bodies no longer can might be better left in the lab—or lavatory, as the case may be. Because scientists are now trying to grow teeth out of human urine.
Published in Cell Regeneration Journal, the new study by a group at the Guangzhou Institutes of Biomedicine and Health has found that urine might be able to be used as a viable source of stem cells, which in turn could be cultivated into small, tooth-like structures. Because though cells expelled through urination do not immediately hold the properties necessary, they can be coaxed into becoming pluripotent stem cells (iPSCs).
By forcing the iPSCs into mimicking both epithelial cells (which eventually become enamel) and mesenchymal cells (which eventually grow into the other three components in teeth: dentin, cementum, and pulp), Dr. Duanqing Pei, of the Chinese Academy of Sciences, was able to create these structures. His team then implanted mice with a mixture of the two materials, using the mouse's mesenchymal cells. And lo and behold, three weeks later, the scientists found themselves in the possession of tooth-like structures. But wait, pee dentures aren't all candy and sunshine. According to the authors of the study:
The method has its limitations - it involves mouse cells, has a success rate of around 30% and the structures were about one-third of the hardness of human teeth.
So although the "tooth-like structure" contained dental pulp, dentin, enamel space, and enamel organ, they're in no way at the point of being a viable replacement. Which isn't really a surprise, considering Professor Chris Mason, a stem cell scientist at the University College London, says that human urine is "probably one of the worst sources" and "you just wouldn't do it this way." So not a ringing endorsement.
But more than just being an awful source of cells in terms of both quantity and quality, urine also carries with it a higher risk of bacterial contamination. You know, because it's urine. So just in case you've been saving up during bathroom breaks for that rainy day when you find yourself in need of a new pair of dentures, probably stop doing that.
Still, though our dreams of a mouth full of pee-bred chompers are dead, you're far less likely to need teeth replacements if you just take care of them in the first place. So remember boys and girls, brush you teeth after every meal, floss regularly, don't drink urine, and above all, always listen to Timmy. [BBC]