First, let's begin with a quick chemistry lesson about this newcomer to popular vocabulary,'BPA' stands for Bisphenol A, a monomer that is commonly used to make many kinds of plastics. In the manufacturing process 'Monomers' are used as basic building blocks. Combining different monomers in different ways yields different kinds of plastics. After manufacturing, many plastics do not contain pure BPA anymore because it is chemically bonded to other molecules to make derivative materials.

So, what's all the fuss about? Well, research suggests that BPA may act like the female hormone estrogen when it enters your body. Too much estrogen can be very problematic. However, it is important to remember that while hormonal effects have been seen in animal tests, no one has shown the same response in human. It's also important to remember that if a plastic is a derivative of BPA, this does not mean that it will have the same estrogen-like effects or that it will leach BPA.

You may be surprised to learn that BPA research has been conducted since the 1930s, so the concern is nothing new.' A simple accident of fate in 1998 brought this issue into sharper focus when a scientist, Patricia Hunt, was conducting routine experiments in her lab at Case Western Reserve University. Apparently, the geneticist discovered that 40 percent of the eggs in a control group of mice quite suddenly developed defects in chromosomal behavior. After a significant sleuthing, they found that the spike in abnormalities occurred just after a zealous lab technician had used a very harsh detergent to clean the mice cages. Evidently, the chemical had caused the breakdown of the plastic and BPA had begun to leach from the cage surfaces.

How big can the problem be? Apparently, the average American consumes 167 bottles of water each year. (That sounds about right for me.) The math on that is astounding! That's 50 billion plastic water bottles a year. (It takes 24 million gallons of oil to produce only ONE billion plastic bottles.) 90% of the cost of a bottle of water is due to the bottle itself and only 23% of those billions of bottles get recycled. Our family is recycling about 80% of the one's we use (and I'm trying to do better), but it will take 700 years for the one's we're throwing away to decompose in the landfill.

Want one more Yikes? These figures on the many billions of bottles going into our landfills do not include soda bottles!

To be sure, recycling will help at the backend of this problem, but what can we do on the frontend? Although completely eliminating exposure to BPA may not be possible, there are steps you can take to reduce your family's exposure to this chemical.

Infant formula: Very recently, all U.S. manufacturers use BPA-based lining on the metal portions of the formula containers. Choose powdered formula. If your baby needs liquid formula look for types sold in glass containers.

Canned foods: BPA leaches from the liner into the food itself. Sensitive groups such as kids and pregnant women should limit canned food consumption. Beverages appear to contain less BPA residues, while canned pasta and soups contain the highest levels.

Safer products and practices: When possible it is best to avoid plastics with the recycling #7 on the bottom, especially for children's food. Plastics with the recycling labels #1, #2 and #4 on the bottom are safer choices and do not contain BPA. Find baby bottles in glass versions, or those made from the safer plastics including polyamine, polypropylene and polyethylene. Soft or cloudy-colored plastic does not contain BPA.

Metal water bottles and thermos coffee cups can have plastic liners. Look for those that are just stainless steel inside.

Heating food in microwaves may cause chemical reactions in the plastic that release BPA. Ceramic, glass, and other microwaveable dishware are good alternatives.

So what about those white plastic dental fillings (my particular area of expertise)? I found some encouraging information with some moderate research on that subject. The bottom line is this– It appears that during the manufacture of dental plastics, BPAis used, but it is converted to Bis-GMA (a different chemical all together). BPA might still be present as an impurityif the chemical reactions do not reach completion, buttwo recent in vitro studies examined components released fromseven commonsealant plastics and detected mainly TEGDMA and Bis-GMA. The authors detected only minute parts per billion of BPA in some saliva specimens for several hours, but BPA,was not detectable beyond three hours after placement of the sealants.

Armed with this knowledge now, I think I can make a good informed decision for my own children ( ages 9, 11, and 15). I now feel confident that the benefits of sealants and other dental plastics still far outweigh the detractions. In my 20 years of dentistry, I have seen these materials completely change the dental futures of both children and adults. They are some of the most important preventative and restorative dental materials ever invented. (If you would like a lot more information about plastic fillings and BPA, see the news story on this website specifically about that.)

For myself, I'm not going to turn our lives upside down over this BPA problem, but I did buy stainless steel water bottles for the kids to take to basketball practice. I'm never going to be tempted to microwave things in plastic containers again, and I'm going to stridently avoid things with #1 and #7 recycling labels,but I'm not going to worry about my fillings.

Hope this is helpful!

Dr. Lynda

Fiddlehead Dental St. Albans