Mercury

“Several European countries have guidelines suggesting that women should not receive mercury-containing dental amalgam fillings during pregnancy. One concern raised by several studies is that mercury exposure during pregnancy may lead to decreased birth weight. A population-based, case-control study was designed to investigate whether placement of mercury-containing fillings in 1993-2000 during pregnancy increased the low-birth-weight risk. Cases and controls were sampled from enrollees of a dental insurance plan with live singleton births in Washington State; 1,117 women with low-birth-weight infants (< 2,500 g) were compared with a random sample of 4,468 women with infants weighing 2,500 g or more. The results indicated that 13% of a dentally insured population had one or more restorative procedures during pregnancy that, regardless of chemical composition, did not increase the low-birth-weight risk (odds ratio = 0.96, 95% confidence interval: 0.88, 1.05). The 4.9% of the women (n = 249) who had at least one mercury-containing amalgam filling during pregnancy were not at an increased risk for a low-birth-weight infant (odds ratio = 0.75, 95% confidence interval: 0.45, 1.26) and neither were women who had 4-11 amalgam fillings placed (odds ratio = 1.00, 95% confidence interval: 0.27, 3.68). This study found no evidence that mercury-containing dental fillings placed during pregnancy increased low-birth-weight risk.”

“Dear Dr. Schwetz and Dr. Carome:

Consumers for Dental Choice has reason to believe that federal regualtions for the protection of human research subjects, including those for children, have been violated by a federally funded research study to test the safety of mercury amalgam dental fillings.”

“This document provides guidance to industry on good risk assessment practices during the development of prescription drug products, including biological drug products.2 This is one of three guidances that were developed to address risk management activities. Specifically, this document discusses the generation, acquisition, analysis, and presentation of premarketing safety data. FDA’s guidance documents, including this guidance, do not establish legally enforceable responsibilities. Instead, guidances describe the Agency’s current thinking on a topic and should be viewed only as recommendations, unless specific regulatory or statutory requirements are cited. The use of the word should in Agency guidances means that something is suggested or recommended, but not required.”

“An 85 year old woman diagnosed with kidney atrophy by ultrasound is found to have high levels of mercury and other toxic metals on laboratory testing. Three large decayed amalgam fillings in the patient’s lower jaw are observed, and the patient is advised to have them removed immediately. A modification of Da Zao Wan (Great Creation Pill) is administered, followed by reductions in both blood urea nitrogen and creatinine. A follow up visit with a nephrologist four years later indicates normal kidney function.”

“BACKGROUND:

Few occupational studies have addressed melanoma in women. Accordingly, our aim was to identify occupations with higher risk of cutaneous melanoma, overall and by site, in Swedish female workers.

METHODS:

All gainfully employed Swedish women were followed-up from 1971 to 1989, using Death/Cancer Registers. Occupational risk ratios adjusted for age, period, town size, and geographic zone were computed for each site. Risk patterns for different sites were then compared.

RESULTS:

High risks were observed among educators, bank tellers, dental nurses, librarians/archivists/curators, horticultural workers, and hatmakers/milliners. Telephone operators and textile workers had increased risk, mainly in the leg. Other occupation-specific site excesses were also found. Upper-limb risks were correlated with head/neck and thorax, though these two sites were not associated. Legs registered a special pattern, with a moderate correlation with upper limbs or thorax, and no correlation with head/neck.

CONCLUSIONS:

Some occupations with possible exposure to arsenic/mercury displayed increased risk. The generalized excess risk among hatmakers/milliners warrants further attention. The weak correlation between legs and other sites suggests site specificity in melanoma risk factors.”

“The effect of the oxidizing agent thimerosal on cytosolic free Ca(2+) concentration ([Ca(2+)]i) and proliferation has not been explored in human osteoblast-like cells. This study examined whether thimerosal alters Ca(2+) levels and causes cell death in MG63 human osteosarcoma cells. [Ca(2+)]i and cell death were measured using the fluorescent dyes fura-2 and WST-1, respectively. Thimerosal at concentrations above 5 microM increased [Ca(2+)]i in a concentration-dependent manner. The Ca(2+) signal was reduced by 80% by removing extracellular Ca(2+). The thimerosal-induced Ca(2+) influx was sensitive to blockade of La(3+), and dithiothreitol (50 microM) but was insensitive to nickel and several L-type Ca(2+) channel blockers. After pretreatment with 1 microM thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor), thimerosal failed to induce [Ca(2+)]i rises. Inhibition of phospholipase C with 2 microM U73122 did not change thimerosal-induced [Ca(2+)]i rises. At concentrations of 5, 10 and 20 microM thimerosal killed 33, 55 and 100% cells, respectively. The cytotoxic effect of 5 microM thimerosal was reversed by 54% by prechelating cytosolic Ca(2+) with BAPTA. Collectively, in MG63 cells, thimerosal induced a [Ca(2+)]i rise by causing Ca(2+) release from endoplasmic reticulum stores and Ca(2+) influx from extracellular space. Furthermore, thimerosal can cause Ca(2+)-related cytotoxicity in a concentration-dependent manner.”

Human milk is the best source of nourishment for the newborn because of its incomparable balanced nutrition and psychological benefits to the infant’s development. Dental fillings containing metallic Hg are the primary source of inorganic Hg contamination of humans. We studied Hg concentrations in the breast milk of mothers during the first month (7-30 d) postnatal in relation to the number of amalgam surfaces. The concentration of total Hg was determined in 23 samples of human milk collected from lactating mothers with a varied number of amalgam dental restorations. The average number of amalgam surfaces was 6.87 (5.81, SD) with a range of 0 to 20. The mean concentration of total Hg in breast milk was 5.73 ng/g (range: 0-23.07). The Pearson correlation coefficient was significant (r = 0.6087, p = 0.0057) between breast-milk Hg and number of amalgam surfaces. In 56.5% of low-fish-eating mothers, the amount of Hg likely to be ingested by breast-fed infants is above the World Health Organization reference.

“Dental amalgam has been controversial ever since it was introduced, early in the nineteenth century, because of its mercury content. People of the Napoleonic era knew full well that mercury was poisonous, and the best that anyone has ever claimed about amalgam is that the mercury exposure may be too small to hurt anyone. Over time, though, a great body of evidence has accumulated showing that mercury is released from amalgam in significant quantities, that it spreads around the body, including from mother to fetus, and that the exposure causes physiological harm. A growing number of dentists, physicians, researchers, citizen activists, politicians, and regulators have come to the conclusion that the time has come to consign dental amalgam to the ‘dustbin of history.’ This article will sketch out the main points of the scientific case against amalgam.”

“25 studies comprising 5821 patients…The Swedish Association of Dental Mercury Patients (Tf) started the more systematic
investigation of symptoms related to amalgam and the effects replacing the alloy with less toxic materials (Tf-bladet, 1986). Since then a considerable number of studies of varying quality have been presented, most of them by dentists. Most of them give a very consistent result: there is hardly any medical treatment which gives so positive results on so many health problems as amalgam removal.”

“Mercury is a very useful metallic element that, while not particularly abundant in nature, can play an important role in the overall health of humans and animals. This article discusses the benefits and toxicological consequences of society’s use of mercury. It also will focus upon the mining, processing, and uses of mercury in the United States, and then highlight the amounts of mercury that are released as wastes. Along the way, three important questions are addressed: How much mercury is released by human activities and by natural events? Do these releases pose a risk either to humans or to the environment in general? How does this information apply to dentistry?”