Laser beam makes dentist's job easier

Advertiser Staff and News Services

Dental cavities can be detected accurately by measuring reflected laser light.

First, let's remind you of what the Stone Age is, when it comes to looking for tooth decay.

The dentist goes at you with his "explorer," that metal instrument with the hook on the end.

"We push, push, push, push, push until we get one that sticks," said Philip Zivnuska, a dentist in Wichita, Kan. Stickiness indicates decay. It's the place that makes a patient yell, "Yikes!" as he goes flying out of the chair.

That system has worked pretty well for years and years. Oh, a decayed tooth gets missed here and there, until the decay spreads. And sometimes a suspicious-looking spot gets drilled even though it isn't really decayed.

Now the explorer has a competitor.

It's called the Diagnodent. It's high-tech, it's painless, and it's 90 percent accurate at spotting decay in seemingly good teeth, compared with 58 percent accuracy the old way, according to a study.

It's especially good at finding decay on the biting surfaces of teeth. They have lots of little grooves where tiny fractures can hide; decay can sneak in there and go to work underneath.

Honolulu dentist Richard Guerin has had one of the laser light tools for about six weeks. Diagnodent is pricey, at about $3,000. But it's a more objective approach to finding tooth decay, Guerin said.

It works by pointing a light, similar in size and shape to a laser pointer, on a tooth. As the laser light hits them, healthy teeth reflect one kind of fluorescent light; decay reflects another.

The laser converts the reflection into a "score" of 1 to 99. Anything higher than 20 is decay.

The control unit also emits a sound as the laser passes over the tooth; the sound changes with different scores, so the dentist can "listen" for decay as well as looking for it.

"This gives you a way of confirming a suspicion that you might have had," Guerin said. "I think it's a significant advancement."

And as much as it can confirm suspicions, it can rule out problems, too, as Zivnuska found when he used the Diagnodent on 6-year-old Patrick Burrus, in for his first appointment.

He showed Patrick's parents a dark spot and said, "I'm real suspicious that's decay." But when he used the Diagnodent, it showed the tooth was healthy.