Credit:Austin Cosmetic Dentist(Flickr)

Silver-colored fillings, officially known as amalgam fillings, contain mercury and have been used by dentists for over a hundred years to treat cavities in teeth. They are known to last longer and less expensive.

However, the FDA is now saying they may have toxic effects on the unborn fetus and young children.

In the past, regulators have warned pregnant women against eating certain fish that contain high levels of mercury, but now the FDA has also agreed to post warnings on the danger mercury in fillings may cause to a developing human's brain, in response to a lawsuit filed on behalf of various groups.

As a result of the lawsuit, the groups agreed on a settlement where the FDA conducted a review of the mercury contained in fillings which was completed in 2009. The FDA concludes that dental amalgam fillings are safe for adults and children ages 6 and above. The amount of mercury measured in the bodies of people with dental amalgam fillings is well below levels associated with adverse health effects.

The American Dental Association doesn't feel the settlement was very significant, because the FDA is not limiting the use of mercury fillings. The dental group has said that they feel the amalgam fillings remain safe for dental patients based on many studies and scientific reviews conducted by both government and independent agencies.

Amalgam fillings contain half mercury and half a combination of other metals, and are used by dentists to patch cavities in teeth. Millions of Americans have these silver fillings and the FDA isn't recommending replacement. The FDA wasn't able to answer whether pregnant women and young children should avoid the fillings based on the most recent information gathered by the advisory panel.

Mercury is a metal that is found naturally in the environment and in water. Fish absorb mercury through the water. It has been shown to effect brain growth and result in cognitive and motor-skill development problems according to the Environmental Protection Agency.

As a result, the FDA and EPA already recommend that women who plan to become pregnant, pregnant women, nursing mothers, and young children avoid eating shark, swordfish, king mackerel, white tuna or tilefish, because of their high quantities of mercury. Now they may begin limiting silver fillings usage or at least require strict warnings.

Although amalgam fillings have been used for many years, but they have become less common because more patients have been opting for the tooth-colored composite fillings for cosmetic reasons.

One may still opt to have silver fillings and feel confident with their decision, but doctors may be required in the near future to inform patients of the dangers due to their mercury content.