Mercury

“In October 2013, a new international binding treaty instrument called the Minamata Convention on Mercury opened for signature in Minamata City, Japan, the site of arguably the worst public health and environmental disaster involving mercury contamination. The treaty aims to curb the significant health and environmental impacts of mercury pollution and includes provisions addressing the mining, export and import, storage, and waste management of products containing mercury. Importantly, a provision heavily negotiated in the treaty addresses the use of dental fillings using mercury amalgam, an issue that has been subject to decades of global controversy. Though use of dental amalgam is widespread and has benefits, concerns have been raised regarding the potential for human health risk and environmental damage from emissions and improper waste management. While the Minamata Convention attempts to address these issues by calling for a voluntary phase-down of dental amalgam use and commitment to other measures, it falls short by failing to require binding and measurable targets to achieve these goals. In response, the international community should begin exploring ways to strengthen the implementation of the dental amalgam treaty provisions by establishing binding phase-down targets and milestones as well as exploring financing mechanisms to support treaty measures. Through strengthening of the Convention, stakeholders can ensure equitable access to global oral health treatment while also promoting responsible environmental stewardship.”

“A harmonized human biomonitoring pilot study was set up within the frame of the European projects DEMOCOPHES and COPHES. In 17 European countries, biomarkers of some environmental pollutants, including urinary cadmium and hair mercury, were measured in children and their mothers in order to obtain European-wide comparison values on these chemicals. The Belgian participant population consisted in 129 school children (6-11years) and their mothers (≤45years) living in urban or rural areas of Belgium. The geometric mean levels for mercury in hair were 0.383μg/g and 0.204μg/g for respectively mothers and children. Cadmium in mother’s and children’s urine was detected at a geometric mean concentration of respectively 0.21 and 0.04μg/l. For both biomarkers, levels measured in the mothers and their child were correlated. While the urinary cadmium levels increased with age, no trend was found for hair mercury content, except the fact that mothers hold higher levels than children. The hair mercury content increased significantly with the number of dental amalgam fillings, explaining partially the higher levels in the mothers by their higher presence rate of these amalgams compared to children. Fish or seafood consumption was the other main parameter determining the mercury levels in hair. No relationship was found between smoking status and cadmium or mercury levels, but the studied population included very few smokers. Urinary cadmium levels were higher in both mothers and children living in urban areas, while for mercury this difference was only significant for children. Our small population showed urinary cadmium and hair mercury levels lower than the health based guidelines suggested by the WHO or the JECFA (Joint FAO/WHO Expert Committee on Food Additives). Only 1% had cadmium level slightly higher than the German HBM-I value (1μg/l for adults), and 9% exceeded the 1μg mercury/g hair suggested by the US EPA.”

Mercury is among the most toxic nonradioactive elements which may cause toxicity even at low doses. Some studies showed release of mercury from dental amalgam fillings in individuals who used mobile phone. This study was conducted to assess the effect of high-field MRI on mercury release from dental amalgam filling. We studied two groups of students with identical tooth decays requiring a similar pattern of restorative dentistry. They were exposed to a magnetic flux density of 1.5 T produced by a MRI machine. 16 otherwise healthy students with identical dental decay participated in this study. They underwent similar restorative dentistry procedures and randomly divided into two groups of MRI-exposed and control arms. Urinary concentrations of mercury in the control subjects were measured before (hour 0) and 48 and 72 hrs after amalgam restoration, using cold vapor atomic absorption spectrometry. Urinary concentrations of mercury in exposed individuals were determined before (hour 0), and 24, 48, 72 and 96 hrs after amalgam restoration. Unlike control subjects, they underwent conventional brain MRI (15 min, 99 slices), 24 hrs after amalgam restoration. The mean±SD urinary mercury levels in MRI-exposed individuals increased linearly from a baseline value of 20.70±17.96 to 24.83±22.91 μg/L 72 hrs after MRI. In the control group, the concentration decreased linearly from 20.70±19.77 to 16.14±20.05 μg/L. The difference between urinary mercury in the exposed and control group, 72 hrs after MRI (96 h after restoration),was significant (p=0.046). These findings provide further support for the noxious effect of MRI (exposure to strong magnetic field)and release of mercury from dental amalgam fillings.

“Provide pre-placement and periodic medical exams for those regularly exposed to mercury with emphasis directed to CNS-central nervous system, skin, lungs, liver, kidneys, and G.I. tract.”

"Clarkson and Magos (2006) provide their perspectives on the toxicology of mercury vapor and dental amalgam. As scientists who are involved in preparing a German federal guideline regarding dental amalgam, we welcome additional scientific data on this issue. However, Clarkson and Magos do not present all the relevant studies in their review. The additional data provided here show that: (a) Dental amalgam is the main source of human total mercury body burden, because individuals with amalgam have 2-12 times more mercury in their body tissues compared to individuals without amalgam; (b) there is not necessarily a correlation between mercury levels in blood, urine, or hair and in body tissues, and none of the parameters correlate with severity of symptoms; (c) the half-life of mercury deposits in brain and bone tissues could last from several years to decades, and thus mercury accumulates over time of exposure; (d) mercury, in particular mercury vapor, is known to be the most toxic nonradioactive element, and is toxic even in very low doses, and (e) some studies which conclude that amalgam fillings are safe for human beings have important methodogical flaws. Therefore, they have no value for assessing the safety of amalgam."

"BACKGROUND:

Methyl mercury (MeHg) and metallic Hg are well known as neurotoxic agents. Dental amalgam contributes significantly to elemental Hg vapour exposure in the general population. There is little information about Hg concentration in human amniotic fluid (AF) of pregnant women and its potential toxic effect on the fetuses.

OBJECTIVE:

Primary to assess the relationship between the presence of detectable mercury (Hg) concentration in human AF, number and surface areas of amalgam fillings of pregnant women; secondary to analyse their obstetric history and perinatal complications.

METHODS:

Seventy-two pregnant women took part in this prospective study. One dentist recorded the dental status, presence, number and surface areas of amalgam fillings. Total Hg concentration in AF was determined in digested samples using automatic cold vapour atomic absorption equipment. The detection limit of Hg in AF, determined from blank readings, was 0.08 ng/ml. To estimate the dependence of the explanatory variables (such as number and surface areas of amalgam fillings, fish consumption, presence of liver or neurological diseases and smoking habits) on mercury concentration several linear regression models were built up. Stepwise logistic regression procedures were running on total sample and on patients with at least one amalgam filling (Positive Filling group = PF). Principal component analysis (PCA) provided two factors, which explained for more the 60% of the variance among the variables.

RESULTS:

The overall mean Hg concentration in AF among all patients was 0.37+/-0.49 ng/ml. Nineteen (26.4%) women had a Hg concentration <0.08 ng/ml (Hg negative group). In 53 (73.6%) patients, with a concentration > or = 0.08 ng/ml (Hg positive group), the mean value of Hg was 0.49+/-0.52 ng/ml. The average number of amalgam fillings was 2.26 +/- 3.19 in the Hg negative group and 5.32+/-3.03 in the Hg positive group (ANOVA one-way p=0.04). A dependence of mercury concentration on number of amalgam fillings (p=0.03), surface area of the amalgam fillings (p=0.04) and fish consumption (p=0.04) was observed but not at a significant level. In stepwise logistic procedure the number of amalgam fillings gave a contribution to the model (p=0.04), although null value was included in the confidence intervals. We observed no statistically significant differences (chi2 test) among the patients with a Hg concentration <0.08 ng/ml (n=19) and those with a concentration > or = 0.08 (n=53) with regard to obstetric history and perinatal complications.

CONCLUSIONS:

Number and surface areas of amalgam fillings influenced positively Hg concentration in AF but not at a significant level. Moreover Hg levels detected in AF were low and no adverse outcomes were observed through pregnancies and in the newborns."

"Abstract: Dentists have a moral and legal responsibility to protect themselves and their employees from high amounts of mercury vapor in the dental office. Time should be taken to train both new and existing office personnel on the nature of the problem, improved housekeeping methods, the importance of reporting problems as they occur and proper clean-up procedures."

“The term Micromercurialism (MM) has long been used to denote those disease conditions in which chronic exposure to very low concentrations of mercury (Hg) is thought to be etiologic (Gerstner and Huff 1977; Nylander 1986; Eggleston and Nylander 1987; Sunderman 1988; Klaassen 1990; Ziff 1992). It is believed to occur in several percent of the population and is reported to be a probable cause of serious disorders including psychoses (Pleva 1994) and Alzheimer’s disease (Thompson et al. 1988). Yet MM is almost never diagnosed because of nonspecific symptoms, and certain complexities in urine excretion of Hg (Klaassen 1990; Gerstner and Huff 1977). We explain a model of MM that predicts two states and, therefore, two populations.”

“Patient health and the safety of dental treatments are the primary goals of California’s dental professionals and Dental Board of California.  The purpose of this fact sheet is to provide you with information concerning the risks and benefit of all dental materials used in the restoration (filling) of teeth.”

“Your dentist is dedicated to protecting and improving your oral health. Because of the wide variety of dental procedures, it is important to talk openly with your dentist. Let your dentist know of any changes to your health since your last visit. This will help your dentist recommend the best treatment options for you. This sheet outlines the most common filling options that are available and will help you decide on the right choice for you. The final choice is between you and your dentist.”