Tooth decay is the most common chronic disease in the U.S. for kids. In fact, more than half of elementary school students will have cavities by the time they're in second grade, according to the National Institutes of Health.
Since the 1970s, dentists have been using tooth-colored fillings that contain derivatives of the controversial chemical bisphenol A (BPA), in favor of the metal amalgam fillings.
Now a new analysis on dental fillings in children suggests these non-metal fillings may contribute to behavioral problems. The study authors caution that their results only point to an association; they say their analysis does not prove that BPA causes any behavior changes.
Researchers looked at data from a previous study called The New England Children's Amalgam Trial, which was designed to examine the overall health effects of metal fillings in children, but also included children with composite or tooth-colored fillings. This study in particular was analyzed because it's really the only one looking at dental composites and behavioral problems, according to lead author Nancy N. Maserejian.
The scientists found that young people who got tooth-colored fillings made with BPA derivatives reported higher rates of anxiety, depression and social stress, compared to children whose fillings were made with metals or other materials. The more fillings a child had, the greater the incidence of behavioral problems, according to the data.
But the researchers are quick to point out that the levels of BPA were not measured in more than 400 children who participated in the study.
"There is a strong suggestion that the associations may be causal, but we can't be certain," says Maserejian, an epidemiologist with the New England Research Institutes. "More research is needed."
BPA is an industrial chemical that's been used in hard plastic products and in the linings of metal and aluminum cans since the 1960s. Concerns about the effects of this chemical were raised as recently as 2008. That's when a report released by the National Toxicology Program expressed "some concern for effects on the brain, behavior, and prostate gland in fetuses, infants, and children at current human exposures to bisphenol A."
BPA has come under scrutiny for possible associations with a variety of health problems including developmental problems in young children and heart disease in adults.
This chemical is an endocrine disruptor, which means it interferes with how hormones work in the body.
In 2010 the U.S. Food and Drug Administration expressed the same concerns as the 2008 report. Earlier this year, the FDA decided not to ban BPA in products made in the United States, cautioning that this announcement was not a final determination. The FDA says it continues to support research examining the safety of BPA.
Experts speculate that dental patients may be exposed to BPA in two ways -- when cavities are filled and various chemicals interact with our saliva, and/or over time as it leaches out due to wear and tear.
When asked about the safety concerns due to BPA raised in this study, Michele Mummert, a spokesperson for Dentsply (a manufacturer of dental cavity composites) said: "Dental composites are one of several safe and effective options to treat tooth decay," and referred CNN to the American Dental Association's website for more information about dental treatment option.
Dr. Joel Berg is the president of the American Academy of Pediatric Dentistry. He supports the use of tooth-colored fillings because he says he knows they help children with cavities.
"Both amalgams and composites [tooth-colored fillings] are safe materials. They are both effective, they have been shown to be effective for years and years," explains Berg. "This is one study that has an early finding in the context of a larger group of studies looking at BPA, in a wide variety of materials where it's much more prevalent than in dental materials."
He also points out that the chemicals used in fillings are constantly improving and that what was used during the time of the original study (1997 to 2005) may be less safe than what we have today.
Frederick vom Saal, a biologist at the University of Missouri and a well-known critic of BPA, sees it differently. "This study provides evidence that the use of BPA-based composites should be re-evaluated."
Despite the lack of agreement on the safety of BPA, neglecting to treat cavities is dangerous and can lead to serious health issues for children, particularly from untreated infections. Which is why Berg says getting children in the habit of brushing and taking care of their teeth is essential.
"Preventing cavities is the message I like to get out to children and parents," says Berg.
He urges parents to discuss any concerns about their child's filling with the pediatric dentist.