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Dental Filling Material Linked to Behavioral Problems in Children
Dental cavities are a very common problem in U.S. children. By the time they are adolescents, 80% will have either filled teeth or teeth with cavities. Cavities have traditionally been filled with amalgam, an alloy of metals including mercury, silver, tin and copper.
Recently, concerns about the potential for mercury poisoning and the desire for a better cosmetic appearance prompted a switch from metal alloys to white fillings made up of composite resins. These are now used in over three-quarters of fillings. While it used to be assumed that the exposure to the restorative materials used in fillings occurred primarily when they were being applied, there is new concern that the physical effect of chewing, as well as the chemical/enzymatic effect of exposure to saliva and food cause ongoing leaching of the filling materials into the system. The clinical significance of this low level exposure has not been established.
A recent study looked at the impact of dental fillings on behavior in young children and compared the psychosocial functioning of children with amalgam fillings to those with BPA containing resin, bisphenol A-glycidyl methacrylate (bisGMA). The researchers wondered whether greater exposure to the BPA dental composites was associated with increased behavior problems.
A chemical component of some dental resins, bisphenol A or BPA, has been under scrutiny for years as a potential toxin with the highest threat to young children. Animal studies have demonstrated that BPA exposure results in increased defensive aggression and hyperactivity. Additionally, a study of 249 mothers and children suggested prenatal BPA exposure was associated with anxiety, depression, and hyperactivity problems during early childhood particularly among girls. The FDA has expressed some concern that in fetuses, infants, and children BPA exposure is linked to neural and behavioral problems, and "...effects on the prostate and mammary gland, and an earlier age at which females attain puberty.” Recently, the FDA has banned BPA in baby bottles because of such concerns.
The study of the effect of filling materials followed 434 children over a five-year period. The children were included in the study if they were ages 6-10 years, had no amalgam restorations, had two or more posterior teeth with cavities which required filling and had not been diagnosed by a physician with psychological, behavioral neurologic, immunosuppressive conditions, or renal disease. The children were then randomized have their cavities repaired with either amalgam or BPA containing resin. They had twice yearly checkups and dental care, including fillings, as needed during the study period.
The children’s behavior, including social and emotional functioning at home and at school was evaluated. Psychosocial assessments were made at the beginning of the study and at follow up visits using the Child Behavior Checklist- Parent Report and the Behavior Assessment of Children- Self Report. These are standardized questionnaires which are used to assess behavior and psychosocial functioning of children.
The results showed the children who had higher cumulative exposure to the composite BPA resin had poorer scores on the scales which rated emotional symptoms, clinical maladjustment, and personal adjustment. The researchers concluded that the greater exposure to the compound was associated with impaired psychosocial function in children as compared to children who were treated with amalgam.
Greater exposure to the resin (more fillings over longer time periods) was consistently associated with scores on behavioral questionnaires that indicated poorer psychosocial functioning at the end of the follow up. “With increasing level and duration of exposure to bisGMA-based composite over five years of follow up, children reported more anxiety, depression, social stress, and interpersonal relationship problems and were more likely to have clinical range scores for parent-reported total problem behaviors. No similar associations were found for amalgam.” The researchers note that it is still unclear whether these behavioral issues can be directly attributed to BPA or to some other chemical component of the composite. This study supports the need for more studies of dental resins including measuring the long term release of their chemicals into the body and studying their health impacts.
Regular dental care and appropriate repair of cavities are essential for the oral health of children and adults and all treatments carry risks and benefits. Parents who have concerns about the products used to treat their children should discuss them with their dentists.
The study appears in the journal, Pediatrics.
August 1, 2012