Effects seen only for fillings that used bis-GMA, a resin derived from bisphenol A
A resin in the most commonly used white composite dental fillings may be linked to subtle neuropsychological deficits in children.
The association appears in reanalyzed data collected from 434 children as part of a trial begun roughly a decade ago. The original study was designed to probe for IQ or other neurobehavioral impacts of the mercury that can be released by metal-amalgam dental fillings. Half of the kids received amalgam fillings for cavities in back teeth, the rest got composite back fillings.
Cavities in front teeth always got composite fillings. Wherever composites were used, baby teeth got a urethane-based resin, while permanent teeth got a resin called bis-GMA that is derived from bisphenol A, or BPA. BPA can mimic the hormonal activity of estrogen and exposure in the womb has been linked to behavioral changes in mice and young children.
The 6- to 10-year olds were then followed for five years, with the children or their parents periodically p