Abstract
We appreciate the comments concerning the exposure of mercury through dental amalgams. As the writers pointed out, release of mercury from dental amalgams is well documented. However, studies that have investigated mercury exposure from dental amalgams have led to different conclusions with some believing dental amalgam-sourced mercury is a major problem and others believing it is not (see reviews by Mutter [2011]; Rathore, Singh, & Pant [2012]). The official position of the American Dental Association (ADA) is that dental amalgams do not pose a significant health risk (ADA, 2017). In a review of epidemiologic studies, Bates (2005) concluded that better-designed studies are needed, and that limitations common to most existing studies are lack of longitudinal design and negative confounding by other factors.
Methylmercury is the most toxic form of mercury; the unborn and young children being the most susceptible (Myers & Davidson, 1998; Olson, 2013). Human exposure to methylmercury through the consumption of contaminated fish has been well documented with significant relationships found among fish consumption patterns and methylmercury levels in human blood (e.g. Schober, et al., 2003; Mahaffey, Clickner, & Jeffries, 2009; United States Environmental Protection Agency, 2013). The unborn and nursing infants can be exposed when methylmercury crosses the placenta (Myers & Davidson, 1998) and through the consumption of contaminated breast milk (Grandjean, Weihe, & White, 1995), respectively. Therefore, avoiding exposure to methylmercury depends on educating patients so they can make appropriate dietary choices. Occupational and environmental health nurses can provide this education to working adults at the workplace. Our review was initiated due to concerns that nurses are not adequately trained to educate workers about methylmercury.
In summary, we do not disagree that dental amalgams release mercury that may be a mode of contamination in humans, even though the extent and clinical significance is uncertain. However, the clinical implications for occupational and environmental health nurses of dental amalgam mercury exposure are quite different from those related to methylmercury exposure through consumption of contaminated fish and seafood. Perhaps in the future, multivariate studies should include both dental amalgam and fish consumption variables to delineate the contribution of each source.