BPA in sealants & Composites

First, a number of sealants contain BPA, a known endocrine disruptor. Recent studies have further detailed the health impact of this substance, reported on at News Inferno:

The latest research, the first large BPA study in humans, published last month by the prestigious Journal of the American Medical Association (JAMA), found a “significant relationship” between exposure to the ubiquitous estrogenic chemical and heart disease, diabetes, and liver problems. Long-standing research points to hormonal disturbances and a variety of cancers and neurological and behavioral problems in adults and children. Also, the National Toxicology Program, part of the Department of Health and Human Services (HHS), has raised concerns about BPA. Of particular concern is childhood exposure BPA that leaches from polycarbonate baby bottles and the linings of infant formula cans. The 2003-4 National Health and Nutrition Examination Survey by the Centers for Disease Control and Prevention (CDC) found detectable levels of BPA in 93 percent of urine samples collected from more than 2,500 adults and children over the age of six. BPA may accelerate puberty and raise a potential risk of cancer and, this month, the journal Environmental Health Perspectives reported that BPA might interfere with chemotherapy treatment.

Additionally, a new review of the FDA’s “BPA is safe” rationale shows that to be flawed at best.

And yet,

Despite these concerns and overwhelming evidence pointing to its dangers, the American Dental Association remains strongly in favor of sealants. “This is such an enormously valuable tool to prevent tooth decay,” said Dr. Leslie Seldin, a New York City dentist and consumer adviser for the American Dental Association. “The BPA issue, I think, is so minuscule in impact that it doesn’t really warrant the attention it’s been getting.” But, in actuality, the amount of BPA exposure can vary depending on the sealant. In a 2006 article in The Journal of the American Dental Association, researchers from the United States Public Health Service and the CDC studied the effects of two dental sealants on 14 men, based on saliva and urine samples and found vast differences based on the sealant used. In patients treated with an Ivoclar Vivadent product called Helioseal F showed no change in urinary or salivary levels of BPA, while patients treated with Delton Light Cure sealant, from Dentsply Ash, were exposed to about 20 times higher doses of BPA.

Even if BPA weren’t an issue, there are other problems with sealants. For starters, direct cured resins such as sealants and composites are never completely polymerized. Consequently, as research by Mark Latta has shown, the material is not fully inert even after placement and can damage any of the delicate periodontal tissues it touches (the gums). In some cases, it may trigger an allergic or immune response.

Further, sealants have been implicated in the development and aggravation of neurocutaneous syndrome (NCS). This disorder is characterized by pus-filled leisons on the skin and painful and irritating sensations on or just under the skin. The sores, of course, make the individual vulnerable to other infection. Dr. Omar Amin in particular has documented many, many cases of NCS over the years and has argued from his research that there is a direct cause-effect relationship between toxic dental materials such as sealants and the development of NCS. This is appears largely due to the presence of toxins such as zinc oxide and ethyltoulene sufonamide in sealants. (You can read more of Dr. Amin’s findings here [PDF].)

We humans have a tendency to think that if a substance doesn’t do immediate harm to us, it must be okay. But more and more, the science is showing us the danger in this view. Before we go placing materials in people’s mouths or bodies, we must diligently look ahead, proceeding with caution and an informed perspective. This is an inherently conservative way of practicing dentistry…and also, we would argue, the sanest.