Minicomputer Helps Dentists Create Porcelain Fillings

A small industrial saw controlled by a minicomputer can carve perfect porcelain fillings for decayed teeth while the patient waits in the dentist’s chair.

The compact unit, manufactured by a Swiss company called Privatdovent, was introduced at a recent Greater New York Dental Meeting, and its promoters say it may someday make the tedious process of tooth restoration quick, perfect and cosmetically attractive.

“It’s a natural-looking restoration because it uses ceramics rather than metal,” said Dr. Werner H. Mormann, professor of preventive dentistry at the University of Zurich who introduced the method to his American colleagues.

“This is what the patient wants.”

The unit, a little larger than a personal computer, can create fillings that fit inside the contour of a badly decayed tooth within five to six minutes, he said. The filling is then bonded onto the remaining section of the patient’s own tooth, which has been cleared of decayed debris.

“It’s a new technique done chairside while the patient is waiting,” Mormann said.

Currently, restoration of a badly decayed tooth takes two visits to the dentist--one to take a plastic impression of the hollowed tooth and a second to fit in the filling molded from metal in the interim.

Plastic impressions are not needed with the computerized unit, Mormann said. Instead, the dentist uses a miniature camera to scan the tooth and record a three-dimensional image of it onto a computer screen.

‘Very, Very Accurate’

“The scanning procedure replaces the traditional impression techniques and is very, very accurate,” Mormann said.

The computer, in turn, guides a small, precision grinding saw contained within the unit. Mormann said the saw cuts a one-inch block of a specially designed porcelain into the shape needed to fit within the tooth.

The filling is removed from the unit and bonded--using techniques already available--to the remains of the patient’s tooth. The procedure is usually accompanied by some filing and drilling to ensure that the reconstructed tooth is smooth and properly shaped, he said.

“In all, it is aesthetic, durable restoration,” he said.

Mormann said the unit has been used to successfully restore the teeth of 200 patients in Switzerland. He said that the restored teeth of the first patients, who underwent the procedure three years ago, are still in good condition and that the bonded fillings have held.

The unit can also be used to cosmetically bond front teeth, creating a computer-designed porcelain veneer that fits over a front tooth much like a false fingernail, he said.

Dentists must currently shape such veneers by hand.

Mormann said the computerized unit will be available to dental schools in the United States next year and should be available to dentists in private practice by 1988 for a charge of about $20,000.

“I don’t think it will be prohibitively expensive,” he said. “It’s small so it can be wheeled around so more than one dentist can use it.”