washingtonpost.com
A Moment Of Tooth
Advances to Regrow Decaying Choppers Offer More to Chew On Than You'd Think

By Joel Garreau
Washington Post Staff Writer
Sunday, January 4, 2009 10:55 PM

As long as there are hockey players, there will be niche markets for false teeth. But the real news about the future of dentures is that there isn't much of one. Toothlessness has declined 60 percent in the United States since 1960. Baby boomers will be the first generation in human history typically to go to their graves with most of their teeth.

And now comes tooth regeneration: growing teeth in adults, on demand, to replace missing ones. Soon.

This can't be good for, among others, television news. Ever notice how much denture adhesive those programs still shill to geezers born too early for the fluoride revolution?

But gumming your groceries is yesterday's news. This may be the last generation of third-graders to think it hilarious to say, "Your teeth are like stars -- they come out at night."

* * *

If you are one of those obedient doobies who listened to your dentist and had your wisdom teeth removed for no particularly urgent reason, you are hosed.

If, however, you are one of those perverse rogues who refuses to fix anything that isn't broken, hold everything! It turns out that wisdom teeth are prolific sources of the kind of adult stem cells needed to grow new teeth for you. From scratch. In your adult life, as you need them. In the near future. According to the National Institutes of Health.

For thousands of years, losing teeth has been a routine part of human aging. That's over. "We're there, right now," says Pamela Robey. "A lot of people will go and never lose a tooth. With good health care and proper habits, there's no reason to lose a tooth," short of a knuckle sandwich.

Robey is chief of the Craniofacial and Skeletal Diseases Branch at the National Institute of Dental and Craniofacial Research, part of the NIH.

The introduction of cavity-preventing fluoride into drinking water and toothpaste is viewed as one of the 10 greatest public health accomplishments of the 20th century, right up there with vaccinations, according to the Centers for Disease Control and Prevention.

It did not occur without controversy. In the renowned 1964 black comedy "Dr. Strangelove," Brig. Gen. Jack D. Ripper (Sterling Hayden) attacks the Soviet Union with nuclear-armed B-52s, hoping to thwart a Communist conspiracy to "sap and impurify" the "precious bodily fluids" of the American people with fluoridated water.

Leslie Seldin has some perspective on this. He graduated from dental school in 1966 and was the editor of "The Future of Dentistry," a report published in 2001 by the American Dental Association.

"When I was growing up" -- in the '50s -- "reaching the teen years you'd develop enormous amounts of decay," he says. It wasn't until the '60s, when most baby boomers were growing up, that fluoridation really started having a major impact. By the '90s, "if new patients came in that were young people, under 30, you really were surprised if you saw significant" cavities.

Fundamentally intact teeth, plus the increased attention paid to gum disease that can loosen them, have brought about a transformation.

"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. We go out of our way to avoid them."

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."

Visions of Cuspids

If we no longer lose our teeth, will we lose our dreams about losing our teeth?

Teeth have great power in symbol and myth. Primitive people commonly adorn themselves with the teeth and claws of conquered animals. You still see shark-teeth necklaces on the chests of young beachgoers -- usually male, presumably attempting to declare their virility.

"The tooth is the only part of the body that, as children, we get money for," says Betty Sue Flowers of the University of Texas, who edited "The Power of Myth" by Joseph Campbell with Bill Moyers. "There's no nail-clipping fairy. There's no hair-cutting fairy."

Since teeth are the archetypal means of attack, loss of one's teeth in dreams signifies "a fear of castration or of complete failure in life," reports J.E. Cirlot in "A Dictionary of Symbols," the authoritative examination of the collective, social and religious meanings of images throughout history.

Freud thought that our extremely common tooth-loss dreams were about sexual guilt. Wow, was he predictable.

"Meaningful symbolic interpretation of teeth in dreams usually comes down to one idea: To lose teeth is to become vulnerable, to lose the first line of defense," says Bernard Welt, professor of arts and humanities at the Corcoran College of Art and Design, where for 25 years he has taught a course about dreams.

"Thus it is not surprising if someone who feels defenseless or abandoned emotionally dreams of losing teeth."

Yes, but does the end of tooth loss mean the end of tooth-loss dreams?

"To the extent that many dreams about losing teeth do seem to be inspired by seeing elderly people lacking teeth and incorporating that as a metaphor for mortality or aging or infirmity of later life, I think that proportion of the dreams would be expected to disappear," says Deirdre Barrett of Harvard, editor of "The New Science of Dreaming."

Welt is not so sure. "Obviously, people dream about being naked or partially clothed in public places -- or about having to take an exam unprepared -- without having these experiences," he says.

And for all we know, the rarer tooth loss becomes, the more nightmarish it will be.

Rise Again

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 -- say ahhhhh. So are adult stem cells, found abundantly in both wisdom and baby teeth -- no embryos required, 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. "The whole tooth -- we've got a long way to go," says Shi.

But his 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. "Depends on how lucky we are, and how good we are."

"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 Taiwan 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.

When you ask Shi how close we are to growing full teeth on demand, he laughs. But his crew has already created a living root using stem cells in a pig. "We did it. It works. We're happy. We still have some questions to answer, but we're working on it."

He expects tooth regeneration "to be pretty common in the future."

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

How about genetically engineered teeth, like a shark's?

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, it turns out, have a genetic mutation that gives them a third set of teeth, which can be induced to erupt if the adult teeth are gone. "We have some great X-rays," says dental researcher MacDougall.

Right now, that is seen as a genetic flaw to be eliminated. But some people see it as a great opportunity: We can learn how to genetically engineer extra teeth. This isn't a bug, it's a feature!

Toothful Culture

New word to know and tell: edentulous. It means having no teeth. Comes up a lot when you talk about West Virginians.

Sadly, the new world in which the CDC eventually expects all but 3 or 4 percent of us to be toothful is not arriving evenly distributed, researchers report. Poverty makes a difference, as do health education, access to quality dental care and culture.

When dental health types talk about "culture," it seems they're talking about what they find in the southern Appalachian highlands. West Virginia is not the poorest state in the union, nor is it even remotely the least educated. Yet a stunning 40.5 percent of all adults over 65 are edentulous, according to the CDC -- more than twice the national average. Kentucky is second with 38.9 percent and Tennessee third with 34.9 percent.

"Certainly lifestyle is a piece of this -- diet, exercise. On the obesity and smoking side, West Virginia ranks very, very high," says Kenneth E. Thorpe, professor of health policy at Emory University and a consultant to the West Virginia legislature on health reform. He also points to "access to early-on primary care. Low-income kids don't see the dentist ever.

"But all rural Appalachia -- it goes back to lifestyle. Lack of exercise, poor diet. Just the fat intake during the day. Cheap, high-calorie fast food is abundant. West Virginia ranks very low on nutritional markers like vegetables, fruits. The diet is very different than in California, Colorado, Utah. And then there's the lack of physical activity."

Less clear is what the story is in a place as advanced as Britain. British teeth are so bad as to have become the stuff of modern legend. In the "Austin Powers" movies, the hero's teeth are a running gag. Toothlessness among Brits over 65 exceeds that of West Virginia, reaching 46 percent, according to the World Health Organization. In Europe, this is a level exceeded only by the likes of Albania, Bulgaria and Bosnia-Herzegovina.

Plan Far Ahead

If you had been a great parent, like the University of Alabama's MacDougall, you would have saved your children's baby teeth in liquid nitrogen as sources of adult stem cells. So now MacDougall has the stem cells of her teenage sons -- Morgan, 17, and Mason, 14 -- from which to create future spare parts.

And you don't.

Slacker.

When she moved from the University of Texas Health Science Center at San Antonio to her current position in Birmingham, she took with her the liquid nitrogen apparatus containing her sons' baby-teeth stem cells. She insisted that the moving van have a generator to keep everything super-cold. And "they drove nonstop," she says.

But that's not the real test of great parenting. MacDougall didn't actually save her children's teeth in liquid nitrogen, she says. She took the teeth and extracted the soft residual tissue that holds the adult stem cells and put that in the liquid nitrogen.

Because she's the kind of mom who cared enough to give the hard part of the teeth back to the boys.

So they could put them under the pillow for the tooth fairy.

View all comments that have been posted about this article.

© 2009 The Washington Post Company