What if damaged teeth could heal themselves? That's the inspiration behind a new project from Harvard and the University of Nottingham to create stem cell stimulating fillings.

Dentists treat hundreds of millions of cavities each year by drilling out the decay and putting in a filling.

But 10 to 15 percent of those fillings fail, says Adam Celiz, a therapeutic biomaterials researcher from University of Nottingham. And that leads to millions of root canals to remove the tooth's pulp, the soft tissue in the center of the tooth that contains the blood vessels, nerves, and connective tissue. A root canal can weaken the tooth, which may eventually need to be pulled.

Celiz and his fellow researchers have developed a new kind of filling made from synthetic biomaterial that can stimulate the growth of stem cells in the pulp of the tooth. Just like regular fillings, the biomaterial is injected into the tooth and hardened with UV light.