Dental Technology Finds Cavities with Light Beam

A lot of research in the field of dentistry has been devoted to early detection of cavities over the last 20 years. New technologies are promising to find cavities that were once tough to locate.

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RENEE MONTAGNE, host:

This is MORNING EDITION from NPR News. I'm Renee Montagne.

SUSAN STAMBERG, host:

And I'm Susan Stamberg.

Now we've put some teeth in our health segment. In a dental checkup here's always that moment of terror when the dentist taps your teeth with a metal probe, looking for cavities. Now two new devices cut the suspense a little bit. They may be able to find cavities earlier than ever. NPR's Nell Boyce reports.

(Soundbite of dental equipment)

NELL BOYCE reporting:

Dentist Michael Blicher is standing in his Washington, DC, office examining one of my molars. It has a suspicious black spot that could be just a stain, or it could be a cavity.

Dr. MICHAEL BLICHER (Dentist): I'm just going to kind of check a little bit with my probe. I don't really get any holes.

(Soundbite of dental equipment)

BOYCE: But then Blicher pulls out something called Diagnadent. It's like a pen that shoots out a beam of red light. A decayed tooth will reflect the light differently than a healthy one. The more decay, the more the machine buzzes.

Dr. BLICHER: That's an indication to me that there is something underneath there.

BOYCE: Something that needs drilling. Thousands of dentists have bought a Diagnadent and interest is growing. Most want it because they feel a real need for a better way to find cavities. Plain old X-rays are pretty good at spotting big cavities or decay on the sides of teeth, but James Bader says it can be hard to find cavities, also known as caries, on the biting surface. He's a dentist at the University of North Carolina.

Dr. JAMES BADER (Dentist, University of North Carolina): Dentists will differ and differ quite a bit in their conclusions about whether a single surface of a tooth is or is not carious.

BOYCE: Bader says the Diagnadent can help dentists figure out what's really going on, but he's troubled by reports that some are using it as their sole diagnostic tool. He says the device can give false positives if the teeth aren't perfectly clean, so if the Diagnadent says you need eight new fillings....

Dr. BADER: I'd be a little worried and would seek some confirmation that those eight fillings were necessary.

BOYCE: Another device, known as the Inspector Pro(ph), also uses light. Not many dentists have it. Instead of sensing decay, it detects subtle changes in a tooth's mineral structure. Those begin before a true cavity forms. A blue light makes the tooth glow green. Weak spots appear gray. Kevin Donly works at the University of Texas Health Science Center in San Antonio. He says the device can find pre-cavities that have been hidden until now.

Mr. KEVIN DONLY (University of Texas Health Science Center, San Antonio): It can see this early demineralization that you could never see visibly; that I can't even see myself see visually.

BOYCE: A touch of fluoride to the weak spot should prevent a real cavity. Donly thinks Inspector Pro could mean the end to the old drill and fill.

Mr. DONLY: I think that we want to get away from a cutting profession and we want to be a preventive profession, but we've never really had the tools to do it.

BOYCE: Now there is a tool to find weak spots, but Donly says more research is needed to figure out whether treating them early will mean fewer fillings later.

Cliff Whall of the American Dental Association worked with a scientific committee that examined both devices. He says they could help, but dentists still need to focus on the patient.

Dr. CLIFF WHALL (American Dental Association): You might have a patient that has a history of having a lot of decay. You'd be more suspicious that if you found something with one of these instruments that that indicates that there's some active decay going on. On the other hand, you might have a patient that never has any cavities, and that kind of patient you'd probably want to follow them over time.

BOYCE: And Whall says if you have any doubts about a diagnosis, it never hurts to get a second opinion before you submit to the drill.

Nell Boyce, NPR News.

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