title: The association between amalgam dental surfaces and urinary mercury levels in a sample of Albertans, a prevalence study.
abstract: OBJECTIVE
  The objective of this study was to quantify the relationship between number of dental amalgam surfaces and urinary mercury levels.
  
  
  METHODS
  This study uses participant data from a large philanthropic chronic disease prevention program in Calgary, Alberta, Canada. Urine samples were analysed for mercury levels (measured in μg/g-creatinine). T-tests were used to determine if differences in urine mercury were statistically significant between persons with no dental amalgam surfaces and one or more dental amalgam surfaces. Linear regression was used to estimate the change in urinary mercury per amalgam surface.
  
  
  RESULTS
  Urinary mercury levels were statistically significantly higher in participants with amalgam surfaces, with an average difference of 0.55 μg/g-creatinine. Per amalgam surface, we estimated an expected increase of 0.04 μg/g-creatinine. Measured urinary mercury levels were also statistically significantly higher in participants with dental amalgam surfaces following the oral administration of 2,3-dimercaptopropane-l-sulfonate (DMPS) and meso-2,3-dimercaptosuccinic acid (DMSA) which are used to mobilize mercury from the blood and tissues.
  
  
  CONCLUSIONS
  Our estimates indicate that an individual with seven or more dental amalgam surfaces has 30% to 50% higher urinary mercury levels than an individual without amalgams. This is consistent with past literature that has identified seven amalgam surfaces as an unsafe level of exposure to mercury vapor. Our analysis suggests that continued use of silver amalgam dental fillings for restorative dentistry is a non-negligible, unnecessary source of mercury exposure considering the availability of composite resin alternatives.
authors.affiliation: Department of Community Health Sciences, University of Calgary, 3rd Floor, TRW Building, 3280 Hospital Drive NW, Calgary, AB T2N 4Z6, Canada. duttond@ucalgary.ca.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Dutton
authors.forename: Ken
authors.initials: K
authors.lastname: Fyie
authors.forename: Peter
authors.initials: P
authors.lastname: Faris
authors.forename: Ludovic
authors.initials: L
authors.lastname: Brunel
authors.forename: Jc Herbert
authors.initials: JH
authors.lastname: Emery