Dental Health Editorial: Dental Sealant Worries over Plastic Chemical Bisphenol-A

What’s Hurting Our Health Now? Water Bottles, Baby Bottles… and Dental Composite?

Perhaps you’ve heard the recent news reports of possible health problems with water bottles and other plastic products.

The chemical causing so much concern is bisphenol A, found in some (but not all) plastics. Research suggests that BPA may act like the female hormone estrogen. While hormonal effects have been seen in animal tests, no one has shown the same response in humans.

A Quick Chemistry Lesson

BPA is a monomer used in manufacturing plastics. Monomers are the basic building blocks of plastics; different monomers combined in different ways make different kinds of plastics.
The monomer BPA is also used to make dental sealants and composites, but these products never contain pure BPA. The BPA is chemically bonded to other molecules, making derivatives such as Bis-GMA.
Just because a chemical is a derivative of BPA does not mean that it will have the same estrogen-like effects of BPA or that it will leach BPA.

However, many health experts urge caution, especially with substances that mimic the effect of hormones. Estrogen is a reproductive hormone with feminizing effects, one that has a dramatic impact on sexual development. Some wonder if BPA may be the reason why girls are hitting puberty so early these days. Others fear that a pregnant woman’s exposure to BPA can damage not just the child growing inside her, but that its effect on the fetus’s gonads could harm her grandchildren as well.

BPA exposure is hard to avoid. The chemical may leach into food from plastic containers (especially when heated). In fact, manufacturers of baby bottles now offer BPA-free bottles.

Though plastic bottles have received the most mainstream attention, dentists need to know about another possible avenue for BPA exposure: dental composites and sealants. The dental sealant bisphenol A dimethylacylate is of particular concern.

Dental composites are created from monomers. Composite resin is often based on bisphenol A glycidyl methacrylate (bis-GMA, also known as Bowen’s monomer). Though bis-GMA and some other monomers are chemical derivatives of BPA, BPA itself is not used in dental composites or sealants.

A 1996 study by Nicolas Olea of Spain’s University of Granada was the first to report detectable levels of BPA in the saliva of patients who had just been given dental sealants. The study is still a source of controversy. Further research suggests that some (but not all) dental sealants do raise a patient’s salivary level of BPA. However, blood levels of BPA do not detectably change, and saliva levels quickly return to normal.

This is the dilemma: Yes, there can be detectable levels of BPA. But are they significant?

Some people will tell you that the EPA says it’s okay and the levels of BPA found in humans are far below the levels found to cause problems in animals.
Others will say that the levels of BPA found in humans are well above the levels found to cause detectable hormonal changes in animals.
Some will tell you that dental products cause negligible BPA exposure when compared to food products, water bottles, environmental pollution, and other sources.
Others will say it’s downright irresponsible for dentists to give young children dental sealants that could damage their reproductive development.
I will straightforwardly tell you that I have no idea if any of this is a big deal or not.

Here are some other resources…

Definitely pro-BPA: Bisphenol-A.org
Somewhat pro-BPA: ADA Statement on BPA
Somewhat anti-BPA: Wikipedia – Bisphenol-A
Definitely anti-BPA: Environmental Health News

I’d like to know what you dentists think! Do you have any concerns about BPA in dental composites and sealants? Have your patients expressed any concerns? (If they haven’t yet, expect them to soon, as the BPA issue gets more press.)