Levels of Bisphenol A in Urine and Saliva Following Placement of Composite Restorations
Condition: Dental Restorations
Study type: Observational

Summary: 
      This study will determine whether placement of composite (white) dental restorations
      (fillings) increases concentrations of bisphenol A (BPA) and its metabolites in saliva and
      urine. These compounds have estrogenic-like properties that have raised concerns about their
      safety. Small amounts of the chemicals can leach out of dental sealants and be detected in
      saliva soon after the sealants are applied. Dental composites also contain some of these
      compounds.

      U.S. Commissioned Corps officers who need fillings as part of their regular dental treatment
      and who select composite (white) restorations instead of amalgam (metal) may be included in
      this protocol. Participants are recruited from among officers receiving dental care at the
      commissioned officers dental clinic in Rockville, Md.

      Participants complete a 15-minute interview to gather information about their recent diet and
      eating patterns. They also provide 3 to 4 urine and saliva samples, some collected before
      their dental restoration and some after treatment.
    

Detailed description: 
      A study by Olea et al in 1996 reported quantities of specific estrogenic compounds, Bisphenol
      A (BPA), bis-glycidyl methacrylate (bis-GMA) and Bis-A-dimethacrylate (bis-DMA) in saliva
      associated with the placement of certain dental sealants. This report raised concern
      regarding the safety of dental sealants and composite restorations. In a subsequent study
      bis-GMA was found to be stable, but bis-DMA was shown to hydrolyze to BPA, which likely
      accounts for the BPA detected in extracts from certain sealants. Another study reported
      detectable amounts of triethylene glycol dimethacrylate (TEGDMA) and BPA diglycidyl ether
      (BADGE) were released from sealants into saliva. All of these compounds have been shown to
      have deleterious effects for specific endpoints in vitro and various endocrine disruptive
      effects in some animal models, although results have not been consistent across animal
      strain, mode of administration, diet and other unknown factors. Detectable levels in plasma
      have not been shown.

      Since there are insufficient data on the leachability concentrations in body fluids of these
      compounds associated with composite fillings in humans it is important to determine whether
      or not there are detectable levels of these compounds associated with the placement of
      composite restorations, and if so, whether the levels are sufficiently below the maximum
      acceptable or reference dose established by the EPA. For bisphenol A the maximum acceptable
      dose is 0.05 milligrams per kilogram of body weight per day (US EPA, 1993).

      The National Institute of Dental and Craniofacial Research, the National Toxicology Program
      of the National Institute of Environmental Health Sciences, and the Commissioned Officers
      Dental Clinic Dentists have a unique opportunity to conduct a collaborative investigation at
      the Commissioned Officers Dental Clinic (CODC) in Rockville, MD involving commissioned
      officers who need dental restorations. This study will determine whether or not the placement
      of composite restorations is associated with the presence of these compounds in saliva. This
      is particularly timely since the number of composite restorations placed by dentists
      practicing in the U.S is rapidly increasing with over 80 million composite restorations
      placed in 1999 (ADA, 2001). It is of relevance to the U.S. Public Health Service Commissioned
      Officers Dental Clinic (CODC) because the CODC places composite materials in its dental
      clinic and wants to ensure that commissioned officers are receiving the best and safest
      possible dental care.
    

Keywords: Dental Materials; Resins; BisDMA; Absorption; Systemic