Growing Teeth from Stem Cells

The future is upon us. The days of growing human organs to replace those we’ve lost or destroyed is just beyond the horizon. Right now our reach may exceed our grasp, but that’ll only be for so long. And the key to artificially growing organs at will…urine!

Urine Luck

Yes, it may sound disgusting, but it’s not like you’re being told to drink it. Also, before we get ahead of ourselves, we’re not talking about generating a lung or a heart. We’re talking about growing teeth from stem cells in urine. Still, it’s a fascinating process that could open a lot of doors to the future.

Stem cells can be harvested from urine. This isn’t news: studies had already shown that stem cells excreted in urine can become induced pluripotent stem cells, or iPSCs. These types of stem cells can differentiate into any of the 3 types of germ layers: endoderm (forms the stomach, colon, liver, pancreas, thyroid, and others), mesoderm (cardiac, smooth, skeletal muscle and kidney tissue), and ectoderm (epidermis, neurons, and pigment cells). If it sounds a bit complicated, it is.

From Urine to Tissue

So it’s been known that stem cells can be harvested from urine. It was only recently, though, in a Chinese study that the iPSCs created from urine were finally used to generate solid organs or tissue. This is the true breakthrough. It begins with using a tissue culture to trigger iPSCs to differentiate into the cell types that lead to tooth growth: epithelial, which forms the enamel (this comes from the ectoderm, mentioned above) and mesenchymal cells, which give rise to the dentin, cementum, and pulp (this comes from mesoderm).

This mixture was then implanted—get this—into the outer layer of a mouse’s kidney. Here the human iPSCs generate the enamel, while the mouse’s mesenchymal cells generate the other 3 components of the tooth. After three weeks, this procedure created a tooth-like structure.

Now it’s important to note that they were “tooth-like.” Their shape was a little off. Their hardness was a 1/3 of the hardness of human teeth. This could be due to the unusual method of generating them, or because, unlike normal teeth, they never had a chance to chew as they were growing. That said, other aspects about them were excellent. Structurally and physically they resembled teeth. They had similar properties of elasticity and had all the same cellular components.

The hope now is to improve and advance, namely:

• To use wholly human cells
• To increase the success rate of tooth formation from its current rate of 30%
• To then implant them into a human jaw and generate a fully functional tooth.

One of the best things about this study is the urine. The fact that stem cells capable of this came from urine is mind-blowing. It also avoids the tricky ethical issue of the usual source of stem cells: human embryos. Growing teeth from stem cells, however, is just the beginning. We’re truly headed towards a brave new world in which we can only guess what dreams may come.

Dr. Potts is a gentle, caring dentist who uses the most advanced materials and procedures available. He practices comfortable, health-centered dentistry, with a strong emphasis on getting to know each patient. In addition to his technical proficiency, Dr. Potts is a careful listener. He makes sure to understand what you want and will explain beforehand what treatment is best for your individual needs, along with all options available to you. Check out our Twitter, Facebook page, and website.