Posted by Larry Hoover on May 3, 2003, at 12:36:56
In reply to Dental Fillings, posted by David Smith on April 29, 2003, at 19:31:44
> Does this information sound credible to anyone?
> Thanks.
>
> http://www.yourhealthbase.com/amalgams.htmlYes, it sounds credible.
About Quackwatch: Dr. Barrett, the dude who runs the site, has been successfully sued for providing biased and defamatory information. Take him with a grain of salt. He generally ignores any science that doesn't fit with his preconceived notions. That's not to say that he's always wrong, but he is often so.
I spent quite a while investigating mercury, and amalgam fillings, as part of a toxicological background study for the World Wildlife Fund. There is *no* safe exposure to mercury, in my perhaps not so humble opinion. Even arsenic (another toxic heavy metal in the same reactivity group as mercury) may be conditionally essential for health (in tiny amounts), but there has never been any evidence that mercury serves any health-giving role. Quite the contrary.
So-called silver amalgams are about 50% by weight in mercury. The mercury is not chemically bound to the other metals; in fact, the other metals are in solution and crystallized in the mercury. There are a number of mechanical (e.g. chewing, bruxism), physical (e.g. hot beverages, saliva), and chemical (saliva again, and bacterial action) processes which liberate mercury from the surface of the amalgam. It is quite possible that mercury vapour is absorbed directly into the brain across the membranes of the naso-pharynx, and via the lungs. Swallowed mercury is less well absorbed, but bacterial transformation in the gut converts it to methyl mercury, which *is* readily absorbed.
You're not going to avoid mercury. General distribution of mercury is increasing in all areas of the environment, most particularly from industrial activity (especially coal burning). What you can do is try to limit exposures in any way you can.
A little bit about mercury toxicology.....
First, about organic mercury, from:
http://www.ansci.cornell.edu/courses/as625/1998term/Cadmium/cadmium.html
"Mercury (MeHg) (and perhaps Hg 2+) exerts its toxic effects through
numerous mechanisms. In neurons, MeHg disrupts calcium homeostasis by
affecting both voltage-gated calcium channels as well as disruption of
intracellular pools. MeHg, like cadmium, binds to sulfydral groups on
cysteine, which may compromise the function of enzymes and ion channels.
MeHg also interacts with DNA and RNA, resulting in reductions in protein
synthesis, and disrupts the structure of the microtubules of neurons. MeHg
poisoning produces oxidative stress in cells. This may occur through
multiple mechanisms: decreased expression and activity of anti-oxidant
enzymes, participation in a Fenton-like reaction by Hg 2+, or disruption of
electron transport in the mitochondria through inhibition of enzymes of the
electron transport chain, and subsequent uncoupling of the e- transport
chain and ATP synthesis (oxidative phosphorylation). Methylmercury has also
been shown to induce programmed cell death (apoptosis) in exposed neurons."Inorganic mercury, as found in amalgams:
http://www.calpoison.org/public/mercury.html
"Long-term exposure (usually work-related) of inhaled vapors is generally
more dangerous than a one-time short exposure. After long-term inhalation
exposure, the nervous system is the main target of toxicity. Symptoms may
occur within weeks but usually develop insidiously over a period of years.
Neurologic symptoms include tremors, headaches, short-term memory loss,
incoordination, weakness, loss of appetite, altered sense of taste and
smell, numbness and tingling in the hands and feet, insomnia, and excessive
sweating. Psychiatric effects are also seen after long-term exposure."From the Agency for Toxic Substances and Disease Registry:
http://www.atsdr.cdc.gov/ToxProfiles/phs8916.html
"A potential source of exposure to metallic mercury for the general
population is mercury released from dental amalgam fillings. An amalgam is
a mixture of metals. The amalgam used in silver-colored dental fillings
contains approximately 50% metallic mercury, 35% silver, 9% tin, 6% copper,
and trace amounts of zinc. When the amalgam is first mixed, it is a soft
paste which is inserted into the tooth surface. It hardens within 30
minutes. Once the amalgam is hard, the mercury is bound within the amalgam,
but very small amounts are slowly released from the surface of the filling
due to corrosion or chewing or grinding motions. Part of the mercury at the
surface of the filling may enter the air as mercury vapor or be dissolved in
the saliva. The total amount of mercury released from dental amalgam
depends upon the total number of fillings and surface areas of each filling,
the chewing and eating habits of the person, and other chemical conditions
in the mouth. Estimates of the amount of mercury released from dental
amalgams range from 3 to 17 micrograms per day (µg/day). The mercury from
dental amalgam may contribute from 0 to more than 75% of your total daily
mercury exposure, depending on the number of amalgam fillings you have, the
amount of fish consumed, the levels of mercury (mostly as methylmercury) in
those fish, and exposure from other less common sources such as mercury
spills, religious practices, or herbal remedies that contain mercury."Amalgam that is left over after a filling is prepared is considered toxic waste, and must be handled under strictly controlled conditions. How is it that amalgam in the mouth, where it is exposed to a variety of degradative processes, is non-toxic? Think about the brilliance of the first dentist who used it: "Duh! I know! Let's store mercury in people's mouths, and we'll tell them it's safe."
At the risk of being excessively long-winded, I'll move on to references you may want to consider.
I'm only home for a few minutes to get a shower, so I won't be around till Wednesday or so.
Lar
Altern Med Rev 1998 Aug;3(4):262-70 Related Articles, Books, LinkOut
Cysteine metabolism and metal toxicity.Quig D.
Doctor's Data, Inc., West Chicago, IL, USA. dquig@doctorsdata.com
Chronic, low level exposure to toxic metals is an increasing global problem. The symptoms associated with the slow accumulation of toxic metals are multiple and rather nondescript, and overt expression of toxic effects may not appear until later in life. The sulfhydryl-reactive metals (mercury, cadmium, lead, arsenic) are particularly insidious and can affect a vast array of biochemical and nutritional processes. The primary mechanisms by which the sulfhydryl-reactive metals elicit their toxic effects are summarized. The pro-oxidative effects of the metals are compounded by the fact that the metals also inhibit antioxidative enzymes and deplete intracellular glutathione. The metals also have the potential to disrupt the metabolism and biological activities of many proteins due to their high affinity for free sulfhydryl groups. Cysteine has a pivotal role in inducible, endogenous detoxication mechanisms in the body, and metal exposure taxes cysteine status. The protective effects of glutathione and the metallothioneins are discussed in detail. Basic research pertaining to the transport of toxic metals into the brain is summarized, and a case is made for the use of hydrolyzed whey protein to support metal detoxification and neurological function. Metal exposure also affects essential element status, which can further decrease antioxidation and detoxification processes. Early detection and treatment of metal burden is important for successful detoxification, and optimization of nutritional status is paramount to the prevention and treatment of metal toxicity.
Altern Med Rev 1998 Jun;3(3):199-207 Related Articles, Books, LinkOut
Dimercaptosuccinic acid (DMSA), a non-toxic, water-soluble treatment for heavy metal toxicity.Miller AL.
Alternative Medicine Review. P.O. Box 25, Dover, ID 83825, USA. alan@thorne.com
Heavy metals are, unfortunately, present in the air, water, and food supply. Cases of severe acute lead, mercury, arsenic, and cadmium poisoning are rare; however, when they do occur an effective, non-toxic treatment is essential. In addition, chronic, low-level exposure to lead in the soil and in residues of lead-based paint, to mercury in the atmosphere, in dental amalgams and in seafood, and to cadmium and arsenic in the environment and in cigarette smoke is much more common than acute exposure. Meso-2,3-dimercaptosuccinic acid (DMSA) is a sulfhydryl-containing, water-soluble, non-toxic, orally-administered metal chelator which has been in use as an antidote to heavy metal toxicity since the 1950s. More recent clinical use and research substantiates this compound s efficacy and safety, and establishes it as the premier metal chelation compound, based on oral dosing, urinary excretion, and its safety characteristics compared to other chelating substances.
Int Arch Occup Environ Health 1994;66(3):209-12 Related Articles, Books, LinkOut
Long-term mercury excretion in urine after removal of amalgam fillings.Begerow J, Zander D, Freier I, Dunemann L.
Medizinisches Institut fur Umwelthygiene, Dusseldorf, Germany.
The long-term urinary mercury excretion was determined in 17 28- to 55-year-old persons before and at varying times (up to 14 months) after removal of all (4-24) dental amalgam fillings. Before removal the urinary mercury excretion correlated with the number of amalgam fillings. In the immediate post-removal phase (up to 6 days after removal) a mean increase of 30% was observed. Within 12 months the geometric mean of the mercury excretion was reduced by a factor of 5 from 1.44 micrograms/g (range: 0.57-4.38 micrograms/g) to 0.36 microgram/g (range: 0.13-0.88 microgram/g). After cessation of exposure to dental amalgam the mean half-life was 95 days. These results show that the release of mercury from dental amalgam contributes predominantly to the mercury exposure of non-occupationally exposed persons. The exposure from amalgam fillings thus exceeds the exposure from food, air and beverages. Within 12 months after removal of all amalgam fillings the participants showed substantially lower urinary mercury levels which were comparable to those found in subjects who have never had dental amalgam fillings. A relationship between the urinary mercury excretion and adverse effects was not found. Differences in the frequency of effects between the pre- and the post-removal phase were not observed.
J Toxicol Clin Toxicol 2000;38(7):697-700 Related Articles, Books, LinkOut
Urinary excretion of trace elements in humans after sodium 2,3-dimercaptopropane-1-sulfonate challenge test.Torres-Alanis O, Garza-Ocanas L, Bernal MA, Pineyro-Lopez A.
Centro Antivenenos, Departamento de Farmacologia y Toxicologia, Facultad de Medicina, Universidad Autonoma de Nuevo Leon, Monterrey Nuevo Leon, Mexico. otorres@ccr.dsi.uanl.mx
OBJECTIVE: To evaluate the effects of intravenous sodium 2,3-dimercaptopropane-1-sulfonate (DMPS, Dimaval) on urinary excretion of essential trace elements in subjects who received this chelating agent as a mercury challenge test. SUBJECTS: Eleven subjects sought medical attention due to concern with the toxicity of mercury released from dental amalgam fillings. DESIGN: The subjects were given DMPS 3 mg/kg intravenously. Spot urine samples were collected 1 hour before and 1 hour after the DMPS dose for laboratory analysis. In addition to mercury, the urinary excretion of copper, zinc, selenium, magnesium, manganese, molybdenum, chromium, cobalt, and aluminum were measured. RESULTS: A significant increase in urinary excretion of mercury (3- to 107-fold) was observed after the DMPS dose. The DMPS treatment led to a 2- to 119-fold increase in copper excretion; 3- to 43.8-fold in selenium excretion; 1.6- to 44-fold in zinc excretion; and 1.75- to 42.7-fold in magnesium excretion. The excretion of manganese, chromium, cobalt, aluminium, and molybdenum remained unchanged. CONCLUSIONS: In this study, an intravenous DMPS challenge test produced a significant increase in mercury excretion and also led to an increased excretion of copper, selenium, zinc, and magnesium.
Occup Environ Med 1995 Feb;52(2):124-8 Related Articles, Books, LinkOut
People with high mercury uptake from their own dental amalgam fillings.Barregard L, Sallsten G, Jarvholm B.
Department of Occupational Medicine, Sahlgrenska University Hospital, Goteborg, Sweden.
OBJECTIVES--To describe people with high mercury (Hg) uptake from their amalgam fillings, and to estimate the possible fraction of the occupationally unexposed Swedish population with high excretion of urinary Hg. METHODS--Three case reports are presented. The distribution of excretion of urinary Hg in the general population was examined in pooled data from several sources. RESULTS--The three cases excreted 23-60 micrograms of Hg/day (25-54 micrograms/g creatinine), indicating daily uptake of Hg as high as 100 micrograms. Blood Hg was 12-23 micrograms/l, which is five to 10 times the average in the general population. No other sources of exposure were found, and removal of the amalgam fillings resulted in normal Hg concentrations. Chewing gum and bruxism were the probable reasons for the increased Hg uptake. Extrapolations from data on urinary Hg in the general population indicate that the number of people with urinary excretion of > or = 50 micrograms/g creatinine could in fact be larger than the number of workers with equivalent exposure from occupational sources. CONCLUSION--Although the average daily Hg uptake from dental amalgam fillings is low, there is a considerable variation between people; certain people have a high mercury uptake from their amalgam fillings.
J Dent Res 1998 Apr;77(4):615-24 Related Articles, Books, LinkOut
Mercury in biological fluids after amalgam removal.Sandborgh-Englund G, Elinder CG, Langworth S, Schutz A, Ekstrand J.
Department of Basic Oral Sciences, Karolinska Institutet, Huddinge, Sweden.
Dental amalgam is the major source of inorganic mercury (Hg) exposure in the general population. The objective of the present study was to obtain data on changes in Hg levels in blood, plasma, and urine following removal of all amalgam fillings during one dental session in 12 healthy subjects. The mean number of amalgam surfaces was 18 (range, 13 to 34). Frequent blood sampling and 24-hour urine collections were performed up to 115 days after amalgam removal, and in eight subjects additional samples of plasma and urine were collected up to three years after amalgam removal. A transient increase of Hg concentrations in blood and plasma was observed within 48 hours after amalgam removal. In plasma, the peak concentrations significantly exceeded the pre-removal plasma Hg levels by, on average, 32% (1.3 nmol/L; range, 0.1 to 4.2). No increase in the urinary Hg excretion rate was apparent after amalgam removal. An exponential decline of Hg was seen in all media. Sixty days after the amalgam removal, the Hg levels in blood, plasma, and urine had declined to approximately 60% of the pre-removal levels. In seven subjects, who were followed for up to three years, the half-lives of Hg in plasma and urine were calculated. In plasma, a bi-exponential model was applied, and the half-life was estimated at median 88 days (range, 21 to 121). The kinetics of Hg in urine (nmol/24 hrs) fit a mono-exponential model with a median half-life of 46 days (range, 35 to 67). It is concluded that the process of removing amalgam fillings can have a considerable impact on Hg levels in biological fluids. After removal, there was a considerable decline in the Hg levels of blood, plasma, and urine, which slowly approached those of subjects without any history of amalgam fillings.
J Dent Res 1985 Aug;64(8):1069-71 Related Articles, Links
Intra-oral air mercury released from dental amalgam.Vimy MJ, Lorscheider FL.
Intra-oral air was analyzed for mercury (Hg) vapor concentration in 46 subjects, 35 of whom had dental amalgam restorations. Measurements were made with a Jerome Hg detector both before and ten min after chewing stimulation. Subjects with dental amalgams had unstimulated Hg vapor concentrations that were nine times greater than basal levels in control subjects with no amalgams. Chewing stimulation in subjects with amalgams increased their Hg concentration six-fold over unstimulated Hg levels, or a 54-fold increase over levels observed in control subjects. Concentrations of Hg measured in intra-oral air larger than those reported in expired air were attributed to the rate and direction of air passage across amalgam surfaces. There were significant correlations between Hg vapor released into intra-oral air after chewing stimulation and the numbers and types of amalgam restorations. It is concluded that intraoral air is a reliable physiological indicator of Hg released from dental amalgam that may reflect a major source of chronic Hg exposure.
J Dent Res 1985 Aug;64(8):1072-5 Related Articles, Links
Serial measurements of intra-oral air mercury: estimation of daily dose from dental amalgam.Vimy MJ, Lorscheider FL.
Serial measurements of Hg concentration in intra-oral air were made during and after chewing stimulation in 35 subjects with occlusal amalgam restorations. Hg concentrations remained elevated during 30 min of continuous chewing and declined slowly over 90 min after cessation of chewing. By curve-fitting and integration analysis of data during these time periods (including corrections for respiratory volume, retention rate of inspired Hg, oral-to-nasal breathing ratios, and consumption of three meals and three snacks per day), we calculated that all subjects received an average daily Hg dose of approximately 20 micrograms. Subjects with 12 or more occlusal amalgam surfaces were estimated to receive a daily Hg dose of 29 micrograms, whereas in subjects with four or fewer occlusal amalgam surfaces, the dose was 8 micrograms. These Hg dosages from dental amalgam were as much as 18-fold the allowable daily limits established by some countries for Hg exposure from all sources in the environment. The results demonstrate that the amount of elemental Hg released from dental amalgam exceeds or comprises a major percentage of internationally accepted threshold limit values for environmental Hg exposure. It is concluded that dental amalgam Hg makes a major contribution to total daily dose.
Clin Prev Dent 1991 May-Jun;13(3):5-7 Related Articles, Links
Long-term dissolution of mercury from a non-mercury-releasing amalgam.Chew CL, Soh G, Lee AS, Yeoh TS.
National University of Singapore.
The hazards of mercury from dental amalgams have long been recognized. This study examined the mercury release from a "non-mercury-releasing" dental amalgam, Composil, over a 104-week period. Four cylindrical specimens were incubated in 10 ml of purified water at 37 degrees C. The incubate was changed at the end of each 24-hour period and assayed for its mercury content at biweekly intervals. Mercury estimation was carried out using cold-vapor, atomic absorption spectrophotometry over a 104-week period. Results showed that the overall mean release of mercury was 43.5 +/- 3.2 micrograms/cm2/24 hr, and the amount of mercury released remained fairly constant during the duration of the experiment. This study showed that Composil releases mercury in quantities that far exceed those detected in other amalgam systems.
J Prosthet Dent 1987 Dec;58(6):704-7 Related Articles, Links
Correlation of dental amalgam with mercury in brain tissue.Eggleston DW, Nylander M.
Department of Restorative Dentistry, University of Southern California, School of Dentistry, Los Angeles.
Data from this project demonstrate a positive correlation between the number of occlusal surfaces of dental amalgam and mercury levels in the brain (p less than .0025 in white matter). This is indirect evidence suggesting that mercury from dental amalgam fillings may contribute to the body burden of mercury in the brain. The toxic levels of mercury in human tissues have not been sufficiently investigated and the amount of mercury in human brain tissue from dental amalgam may or may not be clinically significant. Nevertheless, dental amalgam exposure should be considered in monitoring sources of mercury accumulation in human brain tissue.
Caries Res 2001 May-Jun;35(3):163-6 Related Articles, Links
Dental amalgam fillings and the amount of organic mercury in human saliva.Leistevuo J, Leistevuo T, Helenius H, Pyy L, Osterblad M, Huovinen P, Tenovuo J.
The National Public Health Institute, Antimicrobial Research Laboratory, Turku University, Turku, Finland.
We studied differences in the amounts of organic and inorganic mercury in saliva samples between amalgam and nonamalgam human study groups. The amount of organic and inorganic mercury in whole saliva was measured in 187 adult study subjects. The mercury contents were determined by cold-vapor atomic absorption spectrometry. The amount of organic and inorganic mercury in paraffin-stimulated saliva was significantly higher (p<0.001) in subjects with dental amalgam fillings (n = 88) compared to the nonamalgam study groups (n = 43 and n = 56): log(e) (organic mercury) was linearly related to log(e) (inorganic mercury, r(2) = 0.52). Spearman correlation coefficients of inorganic and organic mercury concentrations with the number of amalgam-filled tooth surfaces were 0.46 and 0.27, respectively. Our results are compatible with the hypothesis that amalgam fillings may be a continuous source of organic mercury, which is more toxic than inorganic mercury, and almost completely absorbed by the human intestine.
FASEB J 1994 Nov;8(14):1183-90 Related Articles, Links
Adverse immunological effects and autoimmunity induced by dental amalgam and alloy in mice.Hultman P, Johansson U, Turley SJ, Lindh U, Enestrom S, Pollard KM.
Department of Pathology, Linkoping University, Sweden.
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.
FASEB J 1990 Nov;4(14):3256-60 Related Articles, Links
Comment in:
FASEB J. 1991 Feb;5(2):236.Whole-body imaging of the distribution of mercury released from dental fillings into monkey tissues.
Hahn LJ, Kloiber R, Leininger RW, Vimy MJ, Lorscheider FL.
Department of Radiology, University of Calgary, Faculty of Medicine, Alberta, Canada.
The fate of mercury (Hg) released from dental "silver" amalgam tooth fillings into human mouth air is uncertain. A previous report about sheep revealed uptake routes and distribution of amalgam Hg among body tissues. The present investigation demonstrates the bodily distribution of amalgam Hg in a monkey whose dentition, diet, feeding regimen, and chewing pattern closely resemble those of humans. When amalgam fillings, which normally contain 50% Hg, are made with a tracer of radioactive 203Hg and then placed into monkey teeth, the isotope appears in high concentration in various organs and tissues within 4 wk. Whole-body images of the monkey revealed that the highest levels of Hg were located in the kidney, gastrointestinal tract, and jaw. The dental profession's advocacy of silver amalgam as a stable tooth restorative material is not supported by these findings.
Antimicrob Agents Chemother 1993 Apr;37(4):825-34 Related Articles, Links
Comment in:
Antimicrob Agents Chemother. 1993 Aug;37(8):1730-1.Mercury released from dental "silver" fillings provokes an increase in mercury- and antibiotic-resistant bacteria in oral and intestinal floras of primates.
Summers AO, Wireman J, Vimy MJ, Lorscheider FL, Marshall B, Levy SB, Bennett S, Billard L.
Department of Microbiology, University of Georgia, Athens 30602.
In a survey of 640 human subjects, a subgroup of 356 persons without recent exposure to antibiotics demonstrated that those with a high prevalence of Hg resistance in their intestinal floras were significantly more likely to also have resistance to two or more antibiotics. This observation led us to consider the possibility that mercury released from amalgam ("silver") dental restorations might be a selective agent for both mercury- and antibiotic-resistant bacteria in the oral and intestinal floras of primates. Resistances to mercury and to several antibiotics were examined in the oral and intestinal floras of six adult monkeys prior to the installation of amalgam fillings, during the time they were in place, and after replacement of the amalgam fillings with glass ionomer fillings (in four of the monkeys). The monkeys were fed an antibiotic-free diet, and fecal mercury concentrations were monitored. There was a statistically significant increase in the incidence of mercury-resistant bacteria during the 5 weeks following installation of the amalgam fillings and during the 5 weeks immediately following their replacement with glass ionomer fillings. These peaks in incidence of mercury-resistant bacteria correlated with peaks of Hg elimination (as high as 1 mM in the feces) immediately following amalgam placement and immediately after replacement of the amalgam fillings. Representative mercury-resistant isolates of three selected bacterial families (oral streptococci, members of the family Enterobacteriaceae, and enterococci) were also resistant to one or more antibiotics, including ampicillin, tetracycline, streptomycin, kanamycin, and chloramphenicol. While such mercury- and antibiotic-resistant isolates among the staphylococci, the enterococci, and members of the family Enterobacteriaceae have been described, this is the first report of mercury resistance in the oral streptococci. Many of the enterobacterial strains were able to transfer mercury and antibiotic resistances together to laboratory bacterial recipients, suggesting that the loci for these resistances are genetically linked. Our findings indicate that mercury released from amalgam fillings can cause an enrichment of mercury resistance plasmids in the normal bacterial floras of primates. Many of these plasmids also carry antibiotic resistance, implicating the exposure to mercury from dental amalgams in an increased incidence of multiple antibiotic resistance plasmids in the normal floras of nonmedicated subjects.
J Dent Res 1998 Jun;77(6):1415-25 Related Articles, Links
Activation of the immune system and systemic immune-complex deposits in Brown Norway rats with dental amalgam restorations.Hultman P, Lindh U, Horsted-Bindslev P.
Department of Health and Environment, Linkoping University, Sweden.
Dental amalgam restorations are a significant source of mercury exposure in the human population, but their potential to cause systemic health effects is highly disputed. We examined effects on the immune system by giving genetically mercury-susceptible Brown Norway (BN) rats and mercury-resistant Lewis (LE) rats silver amalgam restorations in 4 molars of the upper jaw, causing a body burden similar to that described in human amalgam-bearers (from 250 to 375 mg amalgam/kg body weight). BN rats with amalgam restorations, compared with control rats given composite resinous restorations, developed a rapid activation of the immune system, with a maximum 12-fold increase of the plasma IgE concentration after 3 wks (p < 0.001; Mann-Whitney's test). LE rats receiving amalgam restorations showed no significant increase of plasma IgE (p > 0.05). After 12 wks, BN rats with amalgam restorations showed significantly increased (p < 0.05) titers of immune-complex (IC) deposits in the renal glomeruli and in the vessel walls of internal organs. These rats also showed a significant (p < 0.05), from six- to 130-fold, increase in tissue mercury concentration in the concentration order kidney > spleen > cerebrum occipital lobe > cerebellum > liver > thymus, and the tissue silver concentration was significantly (p < 0.05) increased from three- to 11-fold. Amalgam-implanted BN rats showed a significant (p < 0.05) increase in copper concentration in the kidney and spleen, and in kidney selenium concentration. We conclude that dental amalgam restorations release substantial amounts of their elements, which accumulate in the organs and which, in genetically susceptible rats, give rise to activation of the immune system and systemic IC deposits.
Scand J Dent Res 1983 Apr;91(2):150-2 Related Articles, Links
Methylation of mercury from dental amalgam and mercuric chloride by oral streptococci in vitro.Heintze U, Edwardsson S, Derand T, Birkhed D.
The capacity of the oral bacteria Streptococcus mitior, S. mutans and S. sanguis to methylate mercury was investigated in vitro. Mercuric chloride and pulverized dental amalgam in distilled water, respectively, were used as sources of mercury. Methylmercury was found in the bacterial cells of all three tested strains. The results indicate that organic mercury compounds may be formed in the oral cavity.
poster:Larry Hoover
thread:223248
URL: http://www.dr-bob.org/babble/20030429/msgs/224059.html