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“Exposure to mercury vapour or inorganic mercury compounds can impair fertility in laboratory animals. To study the effects of mercury vapour on fertility in women, eligibility questionnaires were sent to 7000 registered dental assistants in California. The final eligible sample of 418 women, who had become pregnant during the previous four years, were interviewed by telephone. Detailed information was collected on mercury handling practices and the number of menstrual cycles without contraception it had taken them to become pregnant. Dental assistants not working with amalgam served as unexposed controls. Women with high occupational exposure to mercury were less fertile than unexposed controls. The fecundability (probability of conception each menstrual cycle) of women who prepared 30 or more amalgams per week and who had five or more poor mercury hygiene factors was only 63% of that for unexposed women (95% CI 42%-96%) after controlling for covariates. Women with low exposure were more fertile, however, than unexposed controls. Possible explanations for the U shaped dose response and limitations of the exposure measure are discussed. Further investigation is needed that uses biological measures of mercury exposure.”

“During a clinical simulation of insertion and removal of dental amalgams, mercury vapor levels increased slightly, but never exceeded the TLV of 0.05 mg/m3. The addition of indium to dental alloy did not affect the amount of mercury vapor released under these conditions.”

“ADP-ribosylation is an essential process in the metabolism of brain neuronal proteins, including the regulation of assembly and disassembly of biological polymers. Here, we examine the effect of HgCl2 exposure on the ADP-ribosylation of tubulin and actin, both cytoskeletal proteins also found in neurons, and B-50/43-kDa growth-associated protein (B-50/GAP-43), a neuronal tissue-specific phosphoprotein. In rats we demonstrate, with both in vitro and in vivo experiments, that HgCl2 markedly inhibits the ADP-ribosylation of tubulin and actin. This is direct quantitative evidence that HgCl2, a toxic xenobiotic, alters specific neurochemical reactions involved in maintaining brain neuron structure.”

“The total mercury concentrations in the liver (Hg-L), the kidney cortex (Hg-K) and the cerebral cortex (Hg-C) of 108 children aged 1 day-5 years, and the Hg-K and Hg-L of 46 fetuses were determined. As far as possible, the mothers were interviewed and their dental status was recorded. The results were compared to mercury concentrations in the tissues of adults from the same geographical area. The Hg-K (n = 38) and Hg-L (n = 40) of fetuses and Hg-K (n = 35) and Hg-C (n = 35) of older infants (11-50 weeks of life) correlated significantly with the number of dental amalgam fillings of the mother. The toxicological relevance of the unexpected high Hg-K of older infants from mothers with higher numbers of dental amalgam fillings is discussed…CONCLUSION: Future discussion on the pros and cons of dental amalgam should not be limited to adults or children with their own amalgam fillings, but also include fetal exposure. The unrestricted application of amalgam for dental restorations in women before and during the child-bearing age should be reconsidered.”

“In the debate about the possible risks with mercury released from dental amalgam fillings (DA), an important point is whether DA can cause serious, pernicious diseases.

The following two patient cases are a contribution to this debate.  They are translated from the Swedish original [1], which contains an evaluation of 100 cases of poisoning and immunological effects in dental amalgam patients, documented in clinical practice, including recovery from most symptoms after amalgam removal.  Twenty-four of the cases have been documented in more detail, some with colour photographs.  The present cases are complemented by a discussion and some references to relevant literature.”

“Dental amalgam fillings are the most important source of mercury exposure in the general population, but their potential to cause systemic health consequences is disputed. In this study, inbred mice genetically susceptible to mercury-induced immune aberrations were used to examine whether dental amalgam may interfere with the immune system and cause autoimmunity. Female SJL/N mice were implanted in the peritoneal cavity with 8-100 mg silver amalgam or silver alloy for 10 weeks or 6 months. Chronic hyperimmunoglobulinemia, serum IgG autoantibodies targeting the nucleolar protein fibrillarin, and systemic immune-complex deposits developed in a time- and dose-dependent manner after implantation of amalgam or alloy. Splenocytes from mice implanted with amalgam or alloy showed an increased expression of class II molecules. The functional capacity of splenic T and B cells was affected in a dose-dependent way: 10 weeks of low-dose and 6 months of high-dose amalgam implantation strongly increased mitogen-induced T and B cell proliferation, whereas 10 weeks of high-dose implantation decreased the proliferation. Not only mercury but also silver accumulated in the spleen and kidneys after amalgam implantation. In conclusion, dental amalgam implantation in a physiological body milieu causes chronic stimulation of the immune system with induction of systemic autoimmunity in genetically sensitive mice. Implantation of silver alloy not containing mercury also induced autoimmunity, suggesting that other elements, especially silver, have the potential to induce autoimmunity in genetically susceptible vertebrates. Accumulation of heavy metals, from dental amalgam and other sources, may lower the threshold of an individual metal to elicit immunological aberrations. We hypothesize that under appropriate conditions of genetic susceptibility and adequate body burden, heavy metal exposure from dental amalgam may contribute to immunological aberrations, which could lead to overt autoimmunity.”

“Previous studies have shown that: (1) different dental amalgams emit different amounts of Hg vapor after surface films have been removed by abrasion (Boyer, 1988); (2) Sn oxide may be the predominant factor in these surface films that inhibit Hg vapor loss (Okabe et al., 1989); and (3) Sn in the Ag-Hg (gamma 1) phase may influence the vapor pressure of gamma 1 (Reynolds, 1974). The purpose of this study was to explore the relationship between Hg vapor emission and the Sn content of the Ag-Hg (gamma 1) phase in dental amalgam. Eleven commercial amalgams were selected whose gamma 1 phases contain different amounts of Sn. Amalgam specimens were ground on 600-grit carborundum paper and immediately placed into an apparatus designed around a gold film Hg vapor detector. Hg vapor loss in air over a 30-minute period was determined, and the log10 Hg loss/volume fraction gamma 1 was plotted vs. the Sn content of the gamma 1 phase for the 11 test amalgams. A linear regression of these data, showing that of the higher the Sn content in gamma 1, the lower the Hg vapor loss, produced a highly significant R2 = 0.94 (p < 0.001). To examine for differences in vapor pressure among alloys, we eliminated the oxidation effect by conducting these same tests in an argon atmosphere. Although the Hg loss was significantly greater in argon than in air, the same differences among alloys were observed. Thus, from the standpoint of both vapor pressure and oxidation, the amount of Sn in the gamma 1 phase of dental amalgam has a significant and specific influence on the potential for Hg vapor emission.”

“Occupational high-dose exposure to metallic mercury can cause immune disturbances in sensitive individuals. Whether low-dose exposure to inorganic mercury from dental amalgam has this effect in humans is one of the issues related to the concept of oral galvanism and is supported by results of animal studies. This study explored some cellular immune factors (B- and T-lymphocytes, T4, T8, monocytes, neutrophilic, eosinophilic, and basophilic granulocytes, and large unstained cells) and some humoral immune factors (immunoglobulins IgG, IgG1, IgG2, IgG3, IgG4, IgA, IgM, IgE, albumin, alfa-1-antitrypsin, orosomucoid, haptoglobin, and antinuclear antibodies) in 41 healthy 15-y-old schoolchildren. The relationship between these factors and amalgam fillings and mercury concentrations in plasma (P-Hg) were investigated. A low, but significant correlation (r = 0.40, p < .05) was found between the number of amalgam surfaces and the P-Hg values, which were low for both sexes (median value = 1.8 nmol/l). There was no significant influence of the number of amalgam surfaces or P-Hg on the immune factors tested, except random findings. The girls had significantly higher values of T8, IgG, and IgG1 than the boys.”

“Several aspects of Hg release from dental amalgam tooth fillings were examined both in vivo and in vitro. Using light microscopy, Hg globules (diameter =1-2µm) were observed on amalgam surfaces. Hg vapour was measured in exhaled air before and after 5 min of gum chewing in three groups of subjects with varying numbers of dental amalgams. Group 1 had symptoms similar to those of chronic low-dose Hg exposure, N=22; Group 2 had no apparent symptoms and were considered healthy, N=20; Group 3 were controls having no amalgam fillings; N=10. Groups 1 and 2 both demonstrated a significant 3-fold increase in Hg vapour levels after chewing, while levels in controls remained undetectable. A mouth rinse with hot water (55°C) in Group 2 resulted in a further increase in Hg vapour levels. Saliva samples (1 ml) from 17 subjects in Group 2, collected before and after chewing, showed a significant 8-fold increase in Hg concentration after chewing. In a fourth group Hg absorption by the oral mucosa was studied, Group 4, N=10. A 50% degree of absorption was found after 3 min. It is concluded that dental amalgam should be considered an unsuitable alloy resulting in long-term Hg exposure and that it is therefore toxicologically unsuitable as a dental filling material.”

“Biological monitoring of mercury in whole blood (B-Hg) or urine (U-Hg) can be used to assess exposure to mercury vapor if the kinetics and other sources of variation are taken into account. Its rapid rise postexposure makes B-Hg a good indicator of recent exposure peaks, while U-Hg (corrected for urinary flow rate) reflects average long-term exposure. However, high intraindividual variation sometimes requires the average of several U-Hg determinations. In the general population, methylmercury from fish and mercury from dental amalgam influence B-Hg and U-Hg, respectively, and must be considered if other exposures are being monitored. The quantitative relations between mercury in biological fluids and critical organs are poorly understood. Monitoring U-Hg is useful for assessing the risk of adverse effects and the need for preventive measures. At average U-Hg levels of about 50 micrograms.g creatinine-1 (28 nmol.mmol creatinine-1) the prevalence of symptoms and slight objective changes in the central nervous system and the excretion of certain urinary proteins are increased.”