Washington ? Silver dental fillings contain mercury, and the government for the first time is warning that they may pose a safety concern for pregnant women and young children.

The Food and Drug Administration posted the precaution on its Web site earlier this month to settle a lawsuit – making the move a victory for anti-mercury activists.

The warning is not aimed at the general population, only at two groups already urged to limit mercury from another source – seafood – because too much can harm a developing brain.

The fillings, formally known as dental amalgams, “contain mercury, which may have neurotoxic effects on the nervous systems of developing children and fetuses,” reads the FDA Web posting.

That doesn’t mean it truly harms, and the FDA advises against removing existing fillings.

The agency still is studying whether the small amount of mercury vapor released by chewing and brushing is enough to cause neurologic disorders or other problems in youngsters.