05/27/2011 08:19 am ET Updated Jul 27, 2011

When the FDA Flip Flops: The Case of Silver Fillings

In a recent post on the different types of cavity fillings that are available, I mentioned that I wasn't a huge fan of dental amalgam fillings -- you know, those silver fillings we all got as kids. I don't like them because they contain Mercury.

I also referenced how the Food and Drug Administration had recently changed its stance on amalgam fillings. I'd like to talk a little more in depth about that today, as I feel it's important.

In a nutshell, here's what happened: For years, the FDA said amalgam fillings were just fine and we believed it. Just look in the mirror for proof -- it's a given that most of you still have an amalgam filling in your mouth somewhere.

Then, the FDA reversed its stance and basically said something like "Ok, wait, maybe this isn't so good for pregnant women and young children."

Then, in 2009, they changed their tune again, and said (once again), that there was little to no risk. The roller coaster does not end, however -- there was another "it's bad" reversal in 2010, which is still their position today.

As of right now, the FDA considers amalgam fillings as class II (higher risk), when it used to be class I (low to no risk).

The first thing that I believe should be somewhat troubling to everyone is the trust factor. In essence, we're not all scientists and, until very recently, "regular people" really didn't have much access to scientific data -- and even if we do, who really has the time to peruse it all and make heads or tails of it? So we trust organizations like the FDA to tell us what is harmful and what isn't.

That trust seems to sometimes be somewhat misplaced. Because really, going back and forth on something like this is not comforting. Are amalgam fillings harmful or not?

Now I know some commenters will extol that we've known this for years and shouldn't always trust the FDA blindly. Hey, I happen to agree. But again, unless you are conducting tests yourself, our knowledge of most things scientific is limited to choosing which "report" or "finding" to believe.

The FDA changed its mind essentially due to pressure from four different groups who all said "Wait -- this is harmful -- take another look." So they took another look and did the about-face.

What this says to me is that the FDA is not infallible. Essentially, what I glean from this situation is that an FDA endorsement is temporary, akin to "as far as we know now, it's ok. But in 20 years, if people start growing a third leg, we'll revisit it".

Again, not exactly comfy.

What's the reason for this? Why not have allof the facts and findings before deciding that something is safe? I suppose one valid reason is that then, nothing would get released. If we had to wait 20, 30 or 50 years to see if a substance is harmful for the long-term, well ... let's just say no new drug would ever see the light of day. Since we don't want that, we're left with the imperfect system that we currently have.

Let's look at a few other substances that were deemed "OK" by the FDA, but turned out to be "not so good" (or the other way around).

• The FDA recently reversed its position on a Menaflex Knee Device. It had been given approval, but then, under pressure, the FDA re-evaluated its position. It would appear that the device was given a speedy approval because it was somewhat similar to others. However, it's fair to note that political and industry pressure may possibly influence the FDA -- and decisions such as this one -- to a degree.

• The FDA also reversed itself on Olestra, a fat substitute. Before 2003, the FDA required that Olestra packaging include warning labels about cramping and loose stools. You probably remember that -- potato chips that could allegedly give you diarrhea. But in 2003, the FDA decided that warning labels were unnecessary. I mean, who would buy chips that could cause "loose stools"? When I think about the commercial interests that may have influenced the FDA's decision, it makes me take pause.

• On a different note, the FDA reversed a stance on liquid Morphine, saying that it can stay on the market. Since liquid morphine is essentially a last resort, end of life, hospice drug, this actually makes sense to me. In my opinion, there is a point where "bad for you" might be irrelevant.

Ultimately, I personally believe that you should trust your gut more than anything. The FDA might be useful in providing a guide as to what's safe and what isn't, but as the previously mentioned reversals indicate -- it's not always perfect.

Until next time, keep smiling.