Dental fillings made from BPA (bisphenol-A), a controversial plastics chemical, have been linked to long-term behavioral changes in children, according to a study that appeared online Monday and will be published in the August print issue of Pediatrics.

The study followed 543 children, ages 6 to 10, who had been given fillings. Some had been given the traditional dental amalgam fillings, or silver fillings, while others had newer types of fillings, CBS News reported. One of those was made of bisphenol A-glycidyl methacrylate (bisGMA)-based composite, which contains BPA.

The study found that children with more exposure to BPA-based fillings had more problems with anxiety and depression than their peers and scored lower in behavioral assessment tests.

"It's a controversial topic in dental research, how much really does leach (from fillings) … and whether or not that would have an effect," study author Dr. Nancy Maserejian, a scientist at the New England Research Institutes in Watertown, Mass., told Reuters.

About 16 percent of children with higher exposure to BPA had behavorial problems. "The association was stronger in kids who had fillings on chewing surfaces, which suggests the filling was more likely to break down with chemicals possibly seeping out," CBS News reported.

The researchers noted that levels of BPA were not measured in more than 400 children involved in the study, CNN reported.

"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."

The question as to whether BPA affects human health remains controversial, U.S. News reported. At this point, there is no reason to be concerned about the health effects of amalgam or the stainless steel crowns used for a cavity, said Dr. Burton Edelstein, a pediatric dentist and professor of dentistry at Columbia University in New York City. "This study raises enough concern about the alternative of amalgam to revisit the value of amalgam."

Rachel Lowry is a reporter intern for the Deseret News.