Effects of X-rays and magnetic resonance imaging on mercury release from dental amalgam into artificial saliva

Abstract

We write to express our concerns with an article by Kursun et al. entitled ‘‘Effects of X-rays and magnetic resonance imaging on mercury release from dental amalgam into artificial saliva’’ that is published in the Oral Radiol 30:142–146 (2014). In this article, the authors have conducted an experiment to investigate if exposure to X-rays or magnetic resonance imaging (MRI) can affect the release of mercury from dental amalgam into artificial saliva. They reported that mercury releasewas significantly increased after exposure to X-rays but exposure toMRI could not alter themercury level [1]. Over the past years, our laboratory has focused on studying the health effects of exposure to some common and/ or occupational sources of electromagnetic fields such as mobile phones and their base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons andMRI. In 2008, we reported that exposure to MRI or microwave radiation emitted by mobile phones can lead to significant rise in the release of mercury from dental amalgam restoration [2]. Recently, we investigated the effects of stronger magnetic fields (1.5 vs. 0.25 T in our early report) and our new findings provided further support for the adverse effect ofMRI as increased release ofmercury from dental amalgam fillings [3]. We believe that the paper published by Kursun et al. has a serious flaw. The authors stated ‘‘After exposure, each sample was poured into a 100-mL glass tube. The samples were then divided into three groups and left in saliva for 1, 2, or 24 h. An equal number of amalgam samples (24 samples) was treated as a control group and not exposed to any processing’’. As these authors did not measure the mercury level before the exposure, their findings can be easily affected by some major confounding factors such as small differences in the surface (area) of the amalgam restorations. They reported that amalgam disks (diameter 3 mm and thickness 1 mm) were prepared in plexiglas molds to model a standard mesial-occlusal-distal cavity. In this light, the basic question we have to ask is ‘‘what was the level of uncertainty in the measurements of the diameter (and possibly the thickness) of amalgamfillings (e.g. 3 mm ± 1 mm, or 3.0 mm ± 0.1 mm)?’’.We hope that these commentswill be useful in obtaining more reliable results in the future.