A Smile for Bile

The ancient Greeks thought an excess of bile could make you angry or melancholy, but Julian Zhu thinks the digestive juice could improve your smile.

Zhu, a chemist at the University of Montreal, hit upon the idea while developing a bile-acid-based gel for tissue repair. He found that combining modified bile acids with silica created a hard plastic—perfect for patching broken pearly whites. The bile plastic matches the durability of plastic composite fillings and is more resistant to cracks. And it doesn’t leach mercury, as many commonly used metal fillings do. Bile occurs naturally in the body, so it wouldn’t cause any harm if the fillings were to decompose over time.

Zhu hopes to have his fillings through clinical trials and into dentists’ offices by 2014. Some people might squirm at the notion of having teeth made of intestinal by-products, “but everybody has bile in their body,” Zhu points out. “Is it really grosser than putting mercury in your mouth?”