Five months after the U.S. Supreme Court gave lawyers the right to advertise their services and prices, the attorney general of Virginia said yesterday that dentists may advertise as well.

Virginia Attorney General Anthony Troy said that "The principles expressed in the (Supreme Court's) decision are fully applicable to professional advertising by dentists."

Last June the Supreme Court ruled that a law prohibiting lawyers from advertising was invalid because it violated the constitutionally protected right of free speech.

Troy's opinion does not have the same weight as a judicial decision, and is not binding on a judge.

Under Virginia law, the state Board of Dentistry has the power to revoke or suspend dentists' licenses if they advertise.

However, after the U.S. Supreme Court issued its reuling affecting lawyers, the dentistry board began to reassess its own rules. "We have not been enforcing the advertising law," dentistry board member Henderson P. Graham of Marion, Va. said yesterday.

Graham said the board is drafting legislation for consideration by the General Assembly that would allow dentists to advertise under certain conditions.

Troy's opinion said that dentists were allowed to publish only truthful advertising for routine services.

Until now, dentists who were considering advertising faced not only a revocation of their licenses by the dentistry board, but also the possibility of prosecution by local commonwealth's attorneys. A spokesman for the attorney general said he knew of no such pending prosecutions, however.

Troy's opinion is the lastest in a series of decisions, the effect of which is to remove advertising restrictions against professionals such as lawyers, pharmacists and now, dentists. The Federal Trade Commission also is seeking to remove restrictions against advertisement by doctors imposed by the American Medical Association. The case is pending.

Troy's decision does not specifically apply to other professions such as doctors. A separate decision in the case of each profession would have to be made, the spokesman said.

The opinion was requested by Del. Glenn McClanan (D-Virginia Beach) on behalf of a constituent, Ronald L. Rosenthal. Rosenthal, a dentist, said yesterday the he sought the opinion because he belongs to a national organization interested in getting rid of illegal back-alley-type dentists who perform some dental services at low cost sna without professional training.

By advertising, Rosenthal said, dentists like those in his organization can inform the public that good, low-cost dental services are available by licensed professionals. One of our aims is to run them (illegal dentists) out of business," Rosenthal said.

The denturists, as Rosenthal calls the unknown numbers of dental technicians who provide dentures and other services in garages and homes, are flourishing across the country, Rosenthal said.

Rosenthal said he also sought the opinion because his organization is interested in providing low-cost services which he believes can be financially possible only through advertising.

"We need a large number of patients to make it work so we need advertising," Rosenthal said.

Last January the Federal Trade Commission accused the American Dental Association, the Virginia Dental Association and the Northern Virginia Dental Society of illegally restraining competition among dentist by prohibiting their members from advertising.

Clark B. Brown, an Arlington dentist and head of the Northern Virginia Dental Society, said the FTC case is still pending, but the ADA has recently informed members that "as long as advertising is ethical, in good taste and not fraudulent, it probably would not violate the code of ethics."

An ADA spokesman was not available yesterday for comment.

The ADA previously stated that "unrestricted advertising would have no economic benefits for the public and instead might lead to serious abuses in the delivery of dental care."