WASHINGTON--The safety of widely used silver fillings made with mercury will get another look this week in light of persistent complaints that they may cause health problems.
Dozens of studies have found no evidence that the fillings are dangerous, except for rare cases of allergic reactions, U.S. health officials say. The Food and Drug Administration will ask a panel of outside experts on Wednesday and Thursday if it agrees with that conclusion or sees reason to worry.
Mercury is known to be toxic to the brain and kidneys, but health officials say the mercury vapors emitted from fillings during brushing and chewing are too small to cause harm.
Also called dental amalgams, the silver fillings are about half mercury and half a combination of other metals. Makers include Dentsply and Danaher Corp. unit Kerr.
The FDA analyzed research since 1997, when the U.S. Public Health Service issued a report saying data did not support claims that silver fillings caused serious health problems in humans. A review of 34 studies produced nothing to contradict that finding, the FDA said in a draft report prepared for the advisory panel meeting.
"The weight of evidence ... does not support the hypothesis that exposure to mercury via dental amalgam restorations causes adverse biological outcomes," the agency said.
Tens of millions of Americans get silver fillings each year, although dentists today often repair cavities with newer materials that are close to tooth color.
The American Dental Association, on its Web site, said the silver fillings remain a valuable option because they are durable, easy to use and relatively inexpensive.
The FDA lists silver fillings with fish consumption and vaccines as the major sources of mercury exposure in the United States. Studies have found people with more silver fillings have higher levels of the substance in their blood and urine, but health officials say the amounts remain below what is hazardous.
Some consumers, however, believe using mercury in dentistry is unnecessary and dangerous given the consensus that other types of mercury exposure can be harmful.
Opponents of mercury fillings plan to file a petition on Tuesday asking the FDA to immediately ban them for pregnant women. Some countries advise dentists not to use silver fillings in women who are expecting.
If the FDA does not act, "we are going to still continue to use it in pregnant women and children even though we know mercury causes brain damage. It's morally and legally unacceptable," said Charles Brown, counsel for Consumers for Dental Choice.