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A significant relationship between mercury exposure from dental amalgams and urinary porphyrins: a further assessment of the Casa Pia children’s dental amalgam trial

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Abstract

Previous studies noted specific changes in urinary porphyrin excretion patterns associated with exposure to mercury (Hg) in animals and humans. In our study, urinary porphyrin concentrations were examined in normal children 8–18 years-old from a reanalysis of data provided from a randomized, prospective clinical trial that was designed to evaluate the potential health consequences of prolonged exposure to Hg from dental amalgam fillings (the parent study). Our analysis examined dose-dependent correlations between increasing Hg exposure from dental amalgams and urinary porphyrins utilizing statistical models with adjustments for the baseline level (i.e. study year 1) of the following variables: urinary Hg, each urinary porphyrin measure, gender, race, and the level of lead (Pb) in each subject’s blood. Significant dose-dependent correlations between cumulative exposure to Hg from dental amalgams and urinary porphyrins associated with Hg body-burden (pentacarboxyporphyrin, precoproporphyrin, and coproporphyrin) were observed. Overall, 5–10% increases in Hg-associated porphyrins for subjects receiving an average number of dental amalgam fillings in comparison to subjects receiving only composite fillings were observed over the 8-year course of the study. In contrast, no significant correlations were observed between cumulative exposure to Hg from dental amalgams and urinary porphyrins not associated with Hg body-burden (uroporphyrin, heptacarboxyporphyrin, and hexacarboxyporphyrin). In conclusion, our study, in contrast to the no-effect results published from the parent study, further establishes the sensitivity and specificity of specific urinary porphyrins as a biomarker for low-level Hg body-burden, and also reveals that dental amalgams are a significant chronic contributor to Hg body-burden.

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Acknowledgments

This study received funding from the non-profit International Academy of Oral Medicine and Toxicology (IAOMT), the non-profit Institute of Chronic Illnesses, Inc., and the non-profit CoMeD, Inc. None of the organizations providing financial support for the present study had any influence on data analyses or conclusions. We wish to thank Lisa Sykes for reviewing the present manuscript.

Conflict of interest

None of the other authors has any conflicts of interest concerning the present study.

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Authors and Affiliations

  1. Institute of Chronic Illnesses, Inc., Silver Spring, MD, USA

    David A. Geier & Thomas Carmody

  2. Genetic Consultants of Dallas, Allen, TX, USA

    Janet K. Kern

  3. University of Texas Southwestern Medical Center, Dallas, TX, USA

    Janet K. Kern

  4. CoMeD, Inc., Silver Spring, MD, USA

    Paul G. King

  5. ASD Centers, LLC, 14 Redgate Ct, Silver Spring, MD, 20905, USA

    Mark R. Geier

Authors
  1. David A. Geier
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  2. Thomas Carmody
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  3. Janet K. Kern
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  4. Paul G. King
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  5. Mark R. Geier
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Corresponding author

Correspondence to Mark R. Geier.

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Geier, D.A., Carmody, T., Kern, J.K. et al. A significant relationship between mercury exposure from dental amalgams and urinary porphyrins: a further assessment of the Casa Pia children’s dental amalgam trial. Biometals 24, 215–224 (2011). https://doi.org/10.1007/s10534-010-9387-0

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  • DOI: https://doi.org/10.1007/s10534-010-9387-0

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