A Food and Drug Administration advisory committee has recommended that the agency bite off some sizable new areas of regulation, all affecting teeth.

For one thing the panel, after a five-year study, has proposed that warning labels be put on some kinds of fluoridated toothpastes, mouthwashes and gels indicating that children under six should use them only under supervision.

More controversial is another recommendation: that the FDA undertake to set "safe" limits on the amount of sugar permitted in processed foods.

The grounds for this last proposal are that sugar -- in the view of the panel that was composed mostly of dentists -- is "the major dietary factor" responsible for tooth decay.

The FDA advisory committee on dentifrice and dental care products is one of 17 panels FDA is set up six years ago to undertake reviews of all over-the-counter drug products.

Their reports and recommendations have been emerging slowly over the past four years and represent a tentative first step in the government's tortoise-paced regulatory process.

The only hare-like characteristic of such panels is how they multiply and breed reports. One FDA source said yesterday the over-the-counter panels may produce from 40 to 100 monographs and recommendations for rules that could exceed 1,000.

The dental care panel's recommendations on fluoride products revolved primarily around the potential danger to children in the use of new mouthwashes and gels.

The toothpaste labeling urging, supervision of children under six was based on findings that they might mistakenly swallow enough flouride when they brush to affect the color of their teeth.

Fluoride mouthwashes and gels, the panel said, should carry a direct warning," "Do not swallow," because the developing teeth of children "may become permanently discolored" by excessive amounts of fluoride.

It was in the sugar and food areas, however, that the panel's suggestions were most wide-ranging.

All packaged foods that contain more than the "safe" sugar level for teeth should be labeled, the panel suggested.

With that recommendation, the panel joined in the already heated controversy over government-required labeling of such products as breakfast cereals, which is before the Federal Trade Commission.

The FDA advisory panel's suggestions, however, went beyond the idea of labeling.

The group suggested that the "FDA encourage industry, institutions, organized dentistry, and other interested parties to perform further studies aimed at identifying [cavity-causing] foods."

Encouragement, one source said yesterday, should come in the form of federal money for such studies. The studies, the panel said, "may eventually result in warnings placed" on those additives "which are especially harmful."

At the same time, the panel said the government should offer the food industry additional money to find food additives that might reduce the cavity-causing effects of sugar.

The FDA has taken the report under advisement.