Dentures May Soon Be a Thing of the Past

"When I started out in dentistry, in my practice it wasn't uncommon for people losing their teeth -- you took out all their teeth and made a denture. You were working on a denture at all times," says Seldin. "Now, five new dentures a year, that's a lot."

So what's the future of dentures?

"Hopefully, they will become a relic," says Mary MacDougall, director of the Institute of Oral Health Research at the University of Alabama. "Like Washington's false teeth."

Regenerating a whole tooth is no less complicated than rebuilding a whole heart, says Songtao Shi, of the University of Southern California, who heads a team working on creating such a tooth.

Not only do you have to create smart tissue (nerves), strong tissue (ligaments) and soft tissue (pulp), you've got to build enamel -- by far the hardest structural element in the body. And you have to have openings for blood vessels and nerves. And you have to make the whole thing stick together. And you have to anchor it in bone. And then you have to make the entire arrangement last a lifetime in the juicy stew of bacteria that is your mouth.

It's a nuisance, but researchers are closing in on it. In fact, they think the tooth will probably be the first complex organ to be completely regenerated from stem cells. In part this is because teeth are easily accessible. So are adult stem cells, found abundantly in both wisdom and baby teeth, and your immune system won't reject your own cells.

Nobody is predicting when the first whole tooth will be grown in a human, although five to 10 years is a common guess.

Shi's team is pursuing what he believes is a practical and immediate result: growing important parts of teeth that he thinks people will want to use right away. They're working on creating a living root from scratch. "I think it will take a year," Shi says.

"How to make a root is real important," says Robey. "Dentists say, 'Give me a root and I can put a crown on it.'"

In addition, "we're really, really close to treating periodontal disease with regeneration," Shi says. Groups in Japan and at the University of Michigan are using stem cells to create hard and soft tissue in humans, he says. The idea is to take a tooth about to fall out and reconnect it firmly.

Oh, but that's not the end of it.

For most children, the adult teeth are there just waiting to come in at the end of the useful life of the baby teeth. But some people have a genetic mutation that gives them a third set of teeth, which can be induced to erupt if the adult teeth are gone.

Some people see this as a great opportunity: We can learn how to genetically engineer extra teeth.

MacDougall has saved her children's baby teeth in liquid nitrogen, so she has the stem cells of her now teen-age sons, Morgan and Mason, from which to create future spare parts.