Fillings, Sealants May Leach BPA Into Kids' Mouths
TUESDAY, Sept. 7 -- The fillings and sealants that many dentists use can expose children to the controversial chemical bisphenol A (BPA), a new analysis indicates, but such exposure is short-lived and it remains unclear whether or not it poses a long-term health risk.
Although these products 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, the researchers explained.
While the study authors 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," explained 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 noted. "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."
Fleisch and her colleagues report their findings in the October issue of Pediatrics.
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.
According to the U.S. Food and Drug Administration, BPA has been used in the manufacturing of hard plastic bottles and metal cans since the 1960s. The agency notes that toxicity testing has indicated that human exposure to small amounts of the chemical is not problematic.
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.
In light of that concern, the FDA in January took "reasonable steps to reduce human exposure to BPA in the food supply" by funding additional BPA research to the tune of $30 million. At the same time, the agency has been working with manufacturers to move away from products that contain the compound.
Fleisch and her team noted, however, that the agency has not banned BPA from the market.
The authors focused their analysis on the use of BPA-laced materials in dental products by reviewing what they characterized as "sparse" and "mixed" findings dating back about 15 years.
Based on their review, they 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 stressed 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," Fleisch noted.
Gargling for about 30 seconds following application of a dental sealant will remove any excess BPA derivatives, she explained, and dentists can also clean off the sealant's surface once it has hardened.
BPA expert Scott Belcher, an associate professor of pharmacology at the University of Cincinnati, said 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 said.
For more on bisphenol A, visit the U.S. Food and Drug Administration.
Posted: September 2010