Friday, April 25, 2008

The Dangers of Bisphenol-A

According to Today's Article the government of Canada intends to ban baby bottles built with the chemical Bisphenol-A (BPA).

They haven't completely banned the use of BPA because our usual daily exposure isn't high enough to warrant concern. But, for babies, the margin should be greater.

BPA can be found in plastic drinking bottles, the lining of tin cans, CDs, and other electronics.

However, there is another source of BPA that I haven't seen listed in any of the articles I've read.

Dental fillings and sealants are made from BPA derivatives. They're white, and the shade can be matched to your teeth colour. You cannot tell if you have a resin filling simply by looking, if it's done right. The traditional amalgam fillings are silvery and are quite visually apparent.

Sealants, in case you haven't been to the dentist in a while, are made of BPA derivatives, like fillings. Dentists put them in the pits of your molars where food, bacteria, and acid are likely to settle, and where your tooth brush is unlikely to clean out. They put the sealant in there to make sure you don't get cavities. It's a lot cheaper than a filling. My dentist put 7 sealants in my mouth recently. All 7 of them cost less than one filling.

In the hours following the fillings or sealants, some BPA can be found in the saliva.

Before you run out and get your BPA fillings replaced with old-fashioned amalgam, read about the risks of amalgam fillings. Summary: Amalgam filling have been linked to multiple sclerosis, muscular dystrophy, Lou Gerig’s disease, chronic fatigue syndrome, arthritis, Alzheimer’s disease, and the notion of a winter sport being played in June isn't just alright, it's a good thing.

Compare that to this article which says that after a day no BPA was found in the saliva of patients who received dental sealants, and the amounts of BPA were 50 000 times smaller than the maximum BPA limits.

That article was from so it may be a bit biased. Here's another study that's not so optimistic.

Amalgam fillings just sort of get wedged in there. Composite resin fillings bond to the tooth. Composite resin fillings can lead the tooth to be sensitive to hot and cold for a few weeks, as well as sensitivity while chewing. I got my fillings 2 months ago (to the day). I'm still a bit sensitive to hot/cold drinks. It doesn't hurt. I can tell it's there.

After a few days my one filling really started to hurt when I ate. My dentist shaved it down (something that probably can't be as easily and safely done with amalgam) and now it hurts a lot less. I could probably get it shaved down some more, but I'm thinking about leaving it there as a painful reminder to have a better diet for my teeth.

It would be better to have your amalgam fillings replaced with the composite resin fillings and live with the small amounts of BPA you might get. I'm not sure how easy or expensive that would be. I'll talk to my dentist the next time I'm there.

As for sealants, lots of dentists recommend them. If you search the internet you're going to find lots of pages singing their praises. Most of these pages are written by dentists, so they're somewhat biased. When reading stories from people who have had them, the story seems to be a bit different. If the sealant isn't put in just right, if one thing goes wrong (the tooth isn't dry enough, etc.) then cavities can form underneath the sealant. Those cavities are very hard for the dentist to find. They cannot be visually identified. Some web sites say that even the x-ray won't find them. You have to wait for the sealants to come off on their own, then you may find them. (Other sites say that it takes an x-ray to see the sub-sealant cavities.)

Let's not forget, when the sealants start to wear down, they will come apart in bits, and you'll likely swallow them. That's a lot of BPA at once. When the sealants break down, it's a wonderful opportunity for bacteria and acid to settle underneath the sealants, where your toothbrush can't get to.

Here's a page with a few anecdotal stories of how sealants ruined teeth.

One more thing to keep in mind: BPA is not water soluble. So it's fat/alcohol soluble. Think about that the next time you take a swig of wine out of your plastic water bottle.


Anonymous said...

I was doing some research about getting my amalgam fillings replaced and found your blog post. I want to add something to your thoughts: You mentioned talking with your dentist about replacing amalgam fillings with composite resin fillings. However, I'm reading a lot about the need to have someone qualified to replace them, as many dentists don't take the necessary precautions to ensure that you are not ingesting mercury particles or vapors while the amalgam fillings are being removed. A holistic dentist can help with this.

Good luck!

Kristi in Seattle

Andrew said...

Yeah, I've heard about that too.

Now to find a holistic dentist where I live....