Newsletter
BETHESDA, Md., USA: Bisphenol A (BPA) is an organic compound used to produce drinking bottles and dental polymers. Now, researchers have found elevated salivary and urinary levels of BPA up to 30 hours after dental restoration, indicating that the chemical temporarily leaches into these body fluids after placement of resin-based composites.
As prior studies have reported large concentrations of BPA in salivary samples collected after sealant material was placed, the researchers aimed to determine whether such concentration changes are also found in saliva and urine after placement of dental composites.
In the study, they assessed concentrations of BPA and five related compounds in 151 saliva specimens and 171 urine specimens provided by male and female patients before and after receiving composite dental restorations. In total, 264 teeth were restored, 123 anterior and 141 posterior, using an estimated average of 120 mg of composite material per patient.
The researchers observed that salivary concentrations of BPA increased within one hour after placement, which mostly returned to pretreatment levels within eight hours. However, they speculated that some compounds continued to leach from the composite after it was placed because they found highly elevated urinary levels of BPA (43 percent) nine to 30 hours after restoration.
In addition, salivary concentrations of BPA were found to be lower for some compounds when a rubber dam was used. However, rubber dams had no effect on urinary concentration. The researchers concluded that longer-term studies are needed to understand how BPA is actually absorbed by the body.
According to the Centers for Disease Control and Prevention, the effects of BPA on human health are largely unknown, although studies have suggested that it affects the reproductive systems of laboratory animals. A study published in January by researchers at the New York University School of Medicine found that even low levels of BPA may put children and adolescents at a higher risk of heart and kidney disease.
According to a survey published by the American Dental Association, resin-based composites were the most widely used restorative material in 2000. In addition, the data indicates that about 121 million resin-based composite restorations were placed by 2006, compared with approximately 52 million amalgam restorations.
The study was conducted by researchers at the National Institute of Dental and Craniofacial Research. It was published in the December issue of the Journal of the American Dental Association.
