Mainstream dentists, you've got some 'splaining to do.

Some of the most dangerous myths about modern dentistry are about to take a tumble--and it starts with mercury. An FDA panel is finally urging the agency to take another look at its use in fillings.

Didn't know mercury was used in fillings? You're not alone: One survey found that 76 percent of Americans were unaware that the toxic metal was the main ingredient in dental amalgam.

And while dentists and the FDA insist that amalgam fillings are safe, just think about that for a minute: It's mercury.

In your mouth.

Does that sound safe to you?

But that's just a gut reaction--let's take a look at the science on this. One expert, biologist G. Mark Richardson, PhD, told the FDA panel that amalgam fillings cause 67 million Americans to exceed safe levels of mercury exposure every day.

And that's using the EPA's numbers.

If you use California's more stringent standards, Dr. Richardson says 122 million Americans would exceed safe exposure levels.

Odds are, you're one of them--as mercury can escape when you grind your teeth or even just chew your food.

Mercury exposure puts adults at risk for neurological disorders such as dementia and Parkison's disease, and kids at risk for developmental problems such as autism.

The longer the FDA waits to act, the greater the risk to millions. But they don't have to act.

They don't even have to take another look at this, because the panel's recommendation is just that: a recommendation.

So don't wait for the feds on this one--there are perfectly safe and acceptable alternatives to mercury out there. If you or your child needs a filling, tell your dentist you want composite--or tell him you'll be finding a new dentist.

And while you're there, make sure you tell him to lay off the fluoride, too.

Despite what you've heard, fluoride isn't safe--and it doesn't even do a very good job of protecting your teeth, either.

A new study finds that the protective coating fluoride supposedly helps form on your teeth to protect the enamel from decay is actual 100 times thinner than previously thought--or just 6 nanometers thick.

It would take 10,000 of these layers to reach the width of a human hair--and scientists say that's way too thin to offer your chompers any real protection.

In fact, ordinary chewing will knock that flimsy layer right off.