BPA Hazard with Dental Fillings, Sealants Studied

< Sep. 08, 2010 > -- A new study looks at the risk of exposure to the chemical bisphenol A (BPA) from dental fillings and sealants used in children.

The fillings and sealants that many dentists use can expose children to BPA, but such exposure is short-lived and it remains unclear whether or not it poses a long-term health risk.

According to the US Food and Drug Administration (FDA), BPA is a chemical used to manufacture many hard plastic bottles and metal-based food and beverage cans since the 1960s. The agency notes that toxicity testing has indicated that human exposure to small amounts of the chemical is not a hazard.

Although dental fillings and sealants do not contain pure BPA, saliva can cause the fillings and sealants to leach. This releases the chemical into the mouth and breaks it down to its pure form, say the researchers.

The new analysis is reported in the medical journal Pediatrics.

Caution Urged by Experts

While the researchers do not recommend a ban of these dental products with pediatric patients, they caution parents and dentists to take steps that could minimize any potential risks associated with exposure to the ubiquitous chemical, which is found in many plastic products and has been linked to health issues such as male impotence, infant behavioral problems, and birth defects.

"The research that exists shows that upon contact with enzymes in the saliva some, but not all, BPA derivatives break down to pure BPA, and that BPA is said to be in saliva for a short time period of up to three hours," explains study author Dr. Abby F. Fleisch, a pediatrician in the department of medicine at Children's Hospital Boston, which is part of Harvard Medical School.

"However, much of the risk that might be associated with this exposure is theoretical," she notes. "So, there's still a need for additional research looking at both systemic absorption - as a result of this BPA exposure - into the blood and the urine, and whether there is a more chronic low-level leaching of BPA underway."

BPA Risk Still Not Defined

Strong, easy-to-use, and translucent, dental resins and sealant composites that contain BPA are a popular tool used to protect teeth from decay and to repair decayed, broken, or malformed teeth.

However, some recent research with laboratory animals has linked BPA exposure to heart health issues, an increased risk for cancer and diabetes, and some degree of sexual dysfunction and hyperactivity. In addition, particular concerns have also been raised about the potential risk to the brain, prostate and behavioral health of young children, infants, and fetuses.

As a result of these concerns, the FDA in January took "reasonable steps to reduce human exposure to BPA in the food supply" by providing $30 million in funding additional BPA research. At the same time, the agency has been working with manufacturers to move away from products that contain the compound.

However, the FDA has not banned BPA from the market, Dr. Fleisch points out.

Take Steps to Minimize Exposure, Researchers Say

Based on their review, the researchers found there is exposure to pure BPA following dental procedures, but it appears to be short-lived. They added that some products contained different variations and concentrations of BPA.

So, while noting that resin-based sealants are a critical tool for maintaining good oral health in children, the study authors called for manufacturers to label their sealant products to help dentists distinguish which formulations are more or less risky.

The research team also stress that steps should be taken to minimize exposure to children and pregnant women "to the greatest extent possible."

"There are simple precautionary application techniques that can be used to dramatically reduce BPA exposure for people getting these sealants or white fillings," Dr. Fleisch note.

Gargling for about 30 seconds following application of a dental sealant will remove any excess BPA derivatives, she explains, and dentists can also clean off the sealant's surface once it has hardened.

BPA expert Scott Belcher, Ph.D., an associate professor of pharmacology at the University of Cincinnati, says the research team's recommendation "is probably the most reasonable choice right now in terms of the tack to be taken."

"Given all the things we don't understand right now about BPA's possible effects, these are common-sense conclusions and recommendations," he says.

Always consult your child's physician, dentist, or other healthcare professional for more information.

More About Dental Sealants

Dental sealants are thin, plastic films painted on the chewing surfaces of the back teeth - molars and premolars - and are highly effective in the prevention of tooth decay (caries and cavities). Dental sealants are particularly effective on the back teeth, as the back teeth contain more hard-to-reach pits and grooves that serve as a host to food debris and plaque build-up.

Because the sealants act as a physical barrier to decay and plaque build-up, in most cases, they provide 100 percent protection. The most important variable is how well the dental sealant adheres to the teeth.

In addition, research has shown that sealants actually stop cavities when placed on top of a slightly decayed tooth. This action seals off the supply of nutrients to the bacteria that causes the cavity.

The dental sealant becomes ineffective when all or part of the bond between the tooth and the sealant is broken.

Sealants are especially beneficial for children because their newly erupted, permanent teeth are most susceptible to cavities and least benefited by fluoride.

According to the Centers for Disease Control and Prevention (CDC), sealants should be used as part of a child's total preventive dental care. However, the CDC reports about only one-third of children between the ages of 6 and 19 have dental sealants.

A complete preventive dental program includes sealants, fluoride, plaque removal, careful food choices, and regular dental care. Patients of all ages can benefit from dental sealants.

The sealant procedure starts with cleaning the surface of the tooth, rinsing the surface to remove all traces of the cleaning agent, and drying the tooth. A solution or gel is applied to the surface of the tooth, including the pits and grooves, to make the surface of the tooth rough. After several seconds, the solution is thoroughly rinsed away with water and the site is dried. The liquid sealant is then applied and allowed to harden.

With proper oral hygiene, sealants may last five to 10 years.

Always consult your child's dentist or other healthcare provider for more information.