Report Examines Tie Between Mercury Exposure and Dental Restorations

The potential negative effects of mercury released from amalgam dental restorative materials and bisphenol A (BPA) leaked from composite resin dental materials have been long debated. And now, a study examining data from a National Health and Nutrition Examination Survey (NHANES) seeks to define the effects of fillings containing these materials on the human body. The study will be published in the December issue of Ecotoxicology and Environmental Safety.

University of Georgia researchers used NHANES data spanning 14,703 subjects between 2003-2004 and 2011-2012. Subjects were divided into three groups based on their total number of dental surface restorations, but without definition of type: amalgam or composite. The study focused primarily on the association between surface dental restorations and blood total mercury; inorganic mercury; methyl mercury; and urinary BPA. Methyl mercury is the most toxic form. They found that patients with more than eight fillings had significantly more total mercury, inorganic mercury, or methyl mercury in their bloodstreams than subjects with eight or fewer restorations.

Dental amalgam is often used to fill caries lesions, due to its low cost and strength. This material, however, comprises 50% mercury. The mercury exposure created by an individual filling is insignificant. But when eight or more teeth are filled with mercury-based dental restorative material, the risk of negative health effects is possible. The researchers stated this data analysis provides the most current review of mercury levels related to dental fillings to date. They also acknowledged little is known about how the mercury from such dental work seeps into the bloodstream. Despite these findings, the average blood mercury levels cited in the study are below the safety threshold established by the World Health Organization and the Environmental Protection Agency.

From Dimensions of Dental Hygiene. November 2016;14(11):14.