WASHINGTON (AP) _ Americans who dread the dentist's drill may get less painful dental visits: The government approved the nation's first laser to repair cavities Wednesday _ and the vast majority of patients who tested it didn't require local anesthesia.

``I've always been scared of dentists,'' said Harry Chulamanis of West Millford, N.J., who had two large cavities filled with the laser. But ``I was astounded. There was no pain at all.''

Calling the system ``medicine for the 21st century,'' the Food and Drug Administration on Wednesday approved Premier Laser Systems' erbium-YAG laser for treating tooth decay. The Irvine, Calif.-based company says the laser is appropriate for many of the 170 million cavities filled annually in the United States.

Dentists already had some lower-powered lasers for use on gums and other soft mouth tissues. But no laser has been allowed directly on teeth until now because of fears the high heat would damage the inner core of a tooth, explained Dr. Susan Runner, FDA's chief of dental devices.

Premier's laser ``has the potential for changing the way dental practice is handled in this country,'' Runner said.

The FDA examined studies of over 600 teeth to declare the laser as safe and effective as a drill. It appeared to cause no side effects, and the laser patients' fillings last as long as fillings in teeth that were drilled, Runner said.

The only two limitations:

_The FDA forbade doctors from using the laser on children. The agency is concerned because teeth's sensitive inner ``pulp'' forms a larger part of the tooth in children and thus might be penetrated by the laser, Runner said. But Premier said it has seen no problems so far in experimental testing of 80 children over age 2.

_Patients and dentists must wear goggles during laser treatment to protect their eyes from the intense light beam.

The laser removes a cavity without the pressure and vibration of a drill, explained Premier chief executive Colette Cozean.

In total testing of over 1,300 teeth, only three patients requested local anesthesia, she said. The FDA cautioned that other patients did report some mild discomfort.

But the pain reduction means many patients won't need either to have an injection or to leave the dentist's office with a mouth numb from Novocain, said Cozean, who had the laser repair two of her teeth without anesthesia. That also cuts off the procedure about 20 minutes per tooth spent waiting for the painkiller to take effect, she added.

The laser also can make a smaller hole than a drill, thus requiring a smaller filling, Cozean said.

And there is some research _ albeit not proof _ that indicates a laser might kill the underlying bacteria that caused the cavity so decay doesn't continue and force the filling to eventually fall out, she said.

Dentists also are studying whether lasers might one day make root canals and other surgeries less painful, FDA's Runner said.

But today, five dentists _ in New Jersey, California, Ohio, Iowa and Colorado _ who conducted Premier's FDA-required testing already have the lasers ready to offer patients.

They also will conduct colleagues the training required before Premier will sell the $39,000 laser systems to other dentists. Premier expects 1 percent of the nation's 120,000 dentists to buy the machines this year.

A filling costs on average $60 to $120, depending on its size, and Cozean said dentists have told her the charge for a laser procedure shouldn't increase that cost by more than an additional $5.