More than 29 million children have a dental restoration. The majority of restorations now placed are composites. Most resin-based composites placed in children contain a derivative of Bisphenol A (BPA) called BPA-glycidyl methacrylate (BisGMA). When BisGMA was developed in 1962, no studies were required by the FDA to evaluate biological toxicity. BPA is a widespread xenoestrogen that may affect brain, endocrine, and reproductive development. National dental organizations maintain the amount of BPA from BisGMA-based dental materials is too small to be relevant to human health. There is scant scientific evidence for or against this assertion. Contrary to this claim, our pilot data and data from the only other prospective study in children show urinary BPA (uBPA) concentrations are a magnitude of 2 to 6-fold higher post-treatment. Studies show exposure to medical products increase BPA concentrations, yet there are no studies in children that quantify BPA exposure from medical products used in anesthesia (tubes, syringes) for dental treatment. We need to determine the contribution of dental-related BPA exposure to overall BPA load, and distinguish between different sources of dental-related BPA exposure.
The aims of this application are to: (1) Quantify the magnitude and duration of BPA exposure resulting from dental treatment; (2) Determine associations between number of BisGMA-based treated surfaces and BPA, overall and by type of material (composites, sealants); and (3) Determine the association between type of anesthesia and BPA. We will measure uBPA concentrations in 210 children 4 to 8 years old receiving BisGMA-based dental materials with different types of sedation at the University of Washington Center for Pediatric Dentistry 2 times before and 4 times after treatment from 24 hours to 16 weeks. To ensure we have sufficient numbers of highly exposed children we will employ stratified sampling. We will recruit children who are treated with <4 surfaces (n=105) and =4 surfaces (n=105) with BisGMA-based dental materials. Within each of these two groups, we will recruit 35 patients in three groups who receive: (1) no sedation, (2) nitrous oxide; or (3) general anesthesia. We will administer surveys to collect demographic data and data on food security and other sources of BPA. We will measure the height and weight of the child, and collect detailed treatment records. We will conduct the first large study in children to comprehensively examine multiple sources of dental-related BPA exposure. Distinguishing BPA from dental materials and medical products used in anesthesia may enable us to develop interventions to reduce dental-related BPA exposure. By oversampling children receiving treatment on =4 surfaces with BisGMA-based dental materials and children receiving GA, we will include high-risk children likely to have high baseline BPA who may receive among the largest amounts of dental-related BPA exposure from materials or anesthesia, and who may be most likely to experience adverse health effects from BPA.
The public health relevance of this project lies in determining the extent to which children receiving dental treatment are exposed to bisphenol A (BPA), a widespread chemical that may affect reproductive, psychological, cognitive, or endocrine-related health. Our findings will determine if studies of health effects from dental-related BPA exposure are needed, may be used to design interventions to reduce dental-related BPA exposure, and may help clinicians make decisions regarding the use of dental materials that may leach BPA.
