Cleaning cavities with a light touch.

Cleaning cavities with a light touch

There's no vibration. No noise. And most important, no pain. The advantages of laser beams over drill bits are legion, says dental researcher Terry Myers. Although the use of lasers on teeth still awaits Food and Drug Administration approval, recently completed clinical tests went so well he expects approval within "maybe three to six months."

Myers, a dental consultant to American Dental Laser, Inc., in Birmingham, Mich., reported results from 150 teeth in 100 patients who had cavities in the enamel, or outer layer, of their teeth. The Nd-YAG laser--which has at its core the rare-earth element neodymium grown on a crystal of yttrium-aluminumgarnet--vaporises soft organic material in dental cavities, but is too weak to damage healthy enamel, he says.

Carbond dioxide lasers, already approved for gum surgery, get too hot for use on teeth, irreversibly damaging the delicate inner pulp. By pulsing the Nd-YAG beam 10 times per second, a dentist can keep the tooth cool enough to prevent such damage. And with each pulse lasting only 30 trillionths of a second--less than a hundred-millionth the time necessary to trigger a pain nerve--the surgery is essentially without sensation except for a feeling of warmth or tingling reported by 10 to 15 percent of patients. "We've never needed any anesthetic," Myers says, noting that the vibration and whine of the old-fashioned drill bit--often interpreted by patients as pain--are also nonexistent in laser dentistry.