Quick profile of a criminal:

He works in a laboratory in his suburban home, mixing exotic substances, guarding his name from strangers, keeping one wary eye open for the law and the other on his workbench.

He is not a dope peddler, not a counterfeiter, not a spy. He learned his craft from his father, he is respected in his community and his services are sought.

He is making false teeth, fitting them and selling them to the people who will use them. And his work is illegal.

The scene is in the Virginia suburbs of Washington, but it could be in any of the other 48 states that make the denturist's craft illegal, punishable by fine or jailing.

Oregon last November became the first state to break from the pack. Voters overwhelmingly approved a ballot issue cemoving the dentists' monopoly over the fitting and selling of false teeth.

Oregon's denturism law, as it is called, will take effect in mid-1980, after standards have been written for dental laboratory technicians who wish to sell the teeth they make directly to patients.

The consumer and senior-citizen groups that pushed for the change think other states will follow suit. The American Dental Association apparently agrees. It sent more than $300,000 to Oregon to combat the denturism law.

The battle in Oregon was only another round in a debate that has gone on for years. Mostly behind closed doors and in their trade journals, dentists and the technicians who make dentures long have argued about the restrictive state laws.

Now it has become a federal case. With a great deal of money and a lot of false teeth hanging in the balance, the debate has become more intense.

The Federal Trade Commission's western regional staff in San Francisco is considering a proposal that would override state laws and allow technicians to provide denture care.

The San Francisco office expects to make its recommendations to the FTC in Washington soon. If the FTC likes the idea, more months or years could go by before hearings and final federal action.

Ann Grover, a staff attorney who headed a two-year nationwide study of the denture situation, said her office's request for comment drew a heavy response -- for and against the idea.

According to FTC calculations, 23.4 million Americans have no teeth of their own. About 80 percent of them have dentures. Another 10 million need either an upper or a lower denture. But many -- no one knows how many -- cannot pay the price.

The FTC staff's study held that about 40 percent of toothless Americans either have no dentures, or have ill-fitting dentures or fail to receive regular dental care.

So, Grover said, a basic point of the inquiry was related to consumer protection: if nondentists could fit and sell the dentures they make, would prices fall and competition increase? Would the people who need them be able to obtain them more readily?

The American Dental Association, the dentists' professional organization, responded to the FTC request for comment with a lengthy attack on the proposal. It cealt more with health than cost.

ADA's major contentions: that untrained technicians have no business in medicine; that denturists cannot recognize bone and oral tissue diseases; that only a dentist can properly prescribe and fit dentures; that regulation should be left in the hands of the states.

The ADA also objected to another proposal that would require dentists to tell patients what portion of their denture-service fee was paid to the laboratory that manufactured the teeth.

ADA's response included a lengthy compilation of affidavits alleging mistreatment and unhappy results among persons who turned to illegal denturists for their false teeth.

Whatever unhappy results may come from the work of denturists, there apparently is another, more felicitous side to the story -- many thousands of denture wearers are pleased and healthy with their illicit, lower-cost choppers.

"Denturism has been going on for 50 years. There is no question that it is widespread," said Markus Ring, a Washingtonian who is a former president of the National Association of Dental Laboratories (NADL).

"There always have been technicians around who would provide teeth for their relatives and friends. By and large, they have caused no catastrophic problems dentally. There is a lot of dentistry being practiced in this country that a denturist could do," he said.

Ring, however, happens to be one of the dental technicians who has no desire to go into denturism. He and many other NADL members say they believe their best work can be done in the lab, not a patient's mouth.

"Oregon is definitely a foot in the door for denturism, and I think it will have drastic reverberations around the country. This situation is a real sleeping giant -- there are too many technicians teed off at dentists these days," Ring said.

There are various reasons for that, but a central reason is related to money. Some denture makers, not convinced of the magic of dentistry, say they feel that dentists are overpaid for inadequate service.

That, in combination with patients' displeasure with their dentists, helps keep the illegal practice of the Northern Virginia denturist flourishing.

"This began as a referral service, with my friends and friends of theirs," he said. "These are people who are afraid of dentists or who feel they have been ripped off by dentists.

"Yes, I can provide them with dentures at lower cost, but my concern is the quality of dentures. The whole delivery system is wrong -- the dentists don't give us information on the shape of a face, the type and color of a tooth and skin. We have no idea what the patient looks like. These dentists are just not doing their job, and that's why my success rate is so high -- the personal attention I can give to each client."

That situation has arisen because very few dentists now produce the teeth they prescribe for patients. The dentist -- or an aide -- takes a gum impression, then farms out the work to a dental laboratory.

The markup -- that is, the professional fee -- varies from dentist to dentist. The FTC found the median price of a denture to be $275. The dentist's laboratory expense for the denture might be $100. The difference is his fee.

Ring and Grover both noted that cut-rate dentists who advertise denture services offer, for the first time, an alternative to patients who otherwise might go toothless.

"The FTC proposal would give patients a wider range," Ring said. "A person who wants price more than quality will be able to find it. I don't see it taking over dentistry, and I think the ADA will be able to live with it -- just as it now lives with the dentists who ought not to be licensed."