Posted by Larry Hoover on May 8, 2003, at 9:57:19
In reply to Dental amalgam increases disease? Or just Hg level » Larry Hoover, posted by mattdds on May 5, 2003, at 14:10:04
> Larry,
>
> You certainly seem to have done your homework on this, and I am overwhelmed by the amount of citations you have provided.
>
> I briefly looked through them, and although the recurrent theme is that mercury is that mercury is indeed a neurotoxin, and definitely an environmental problem as far as disposal, I still am not convinced that there is any correlation between dental amalgams and actual disease. Do you know of any such convincing evidence? I am not aware of any. I don't mean evidence showing how much mercury is liberated during mastication, I mean actual epidemiological evidence linking, e.g. depression to the amount of restored tooth surfaces in amalgam.
>
> Don't you think this would simplify things a bit? Because until we have real epidemiological evidence linking amalgam fillings to real diagnosable diseases, we are making rather large inductive leaps that cannot be considered good science. So all the discussion about mercury levels liberated during mastication, etc. seems like somewhat of a waste of time, when we could just cut to the chase and ask "does mercury used in a dental setting cause an increase in systemic diseases, or psychiatric problems?". As of now I think the answer is an unequivocal "NO, it does not".The problem is that the correlation between these two parameters has been little studied. It is an axiom in science, "The absence of evidence is not evidence of absence." There have been some reasonably large epidemiological reports finding no relationship, but in some studies within preselected populations, there have been correlations. Here are a few abstracts that are suggestive of physical, psychological and behavioural impacts directly linked to amalgam, or similar exposures:
J Nephrol 2002 Mar-Apr;15(2):171-6
Mercury in dental restoration: is there a risk of nephrotoxicity?Mortada WL, Sobh MA, El-Defrawy MM, Farahat SE.
Urology and Nephrology Center, Mansoura University, Faculty of Science, Egypt.
BACKGROUND: Concern has been voiced about exposure to mercury (Hg) from dental amalgam fillings, and there is a need to assess whether this leads to signs of nephrotoxicity. METHODS: A total of 101 healthy adults (80 males and 21 females) were included in this study. The population as grouped into those having amalgam fillings (39 males and 10 females) and those without (41 males and 11 females). Hg was determined in blood, urine, hair and nails to assess exposure. Urinary excretion of beta2-microglobulin (beta2M), N-acetyl-beta-D-glucosaminidase (NAG), gamma-glutamyltransferase (gammaGT) and alkaline phosphatase (ALP) were determined as markers of tubular damage. Albuminuria was assayed as an early indicator of glomerular dysfunction. Serum creatinine, beta2M and blood urea nitrogen (BUN) were determined to assess glomerular filtration. RESULTS: Hg levels in blood and urine were significantly higher in persons with dental amalgam than those without; in the dental amalgam group, blood and urine levels of Hg significantly correlated with the number of amalgams. Urinary excretion of NAG, gammaGT and albumin was significantly higher in persons with dental amalgam than those without. In the amalgam group, urinary excretion of NAG and albumin significantly correlated with the number of fillings. Albuminuria significantly correlated with blood and urine Hg. CONCLUSION: From the nephrotoxicity point of view, dental amalgam is an unsuitable filling material, as it may give rise to Hg toxicity. Hg levels in blood and urine are good markers of such toxicity. In these exposure conditions, renal damage is possible and may be assessed by urinary excretions of albumin, NAG, and gamma-GT.
Sci Total Environ 1990 Dec 1;99(1-2):23-35The relationship between mercury from dental amalgam and the cardiovascular system.
Siblerud RL.
Department of Physiology, College of Veterinary Medicine and Biological Sciences, Colorado State University, Fort Collins 80523.
The findings presented here suggest that mercury poisoning from dental amalgam may play a role in the etiology of cardiovascular disorders. Comparisons between subjects with and without amalgam showed amalgam-bearing subjects had significantly higher blood pressure, lower heart rate, lower hemoglobin, and lower hematocrit. Hemoglobin, hematocrit, and red blood cells were significantly lower when correlated to increased levels of urine mercury. The amalgam subjects had a greater incidence of chest pains, tachycardia, anemia, fatigue, tiring easily, and being tired in the morning. The data suggest that inorganic mercury poisoning from dental amalgam does affect the cardiovascular system.
Am J Psychother 1989 Oct;43(4):575-87
The relationship between mercury from dental amalgam and mental health.
Siblerud RL.
Colorado State University, Department of Physiology, Fort Collins.
The findings presented here suggest that mercury poisoning from dental amalgam may play a role in the etiology of mental illness. Comparisons between subjects with and without amalgam showed significant differences in subjective reports of mental health. Subjects who had amalgams removed reported that symptoms of mental illness lessened or disappeared after removal. The data suggest that inorganic mercury poisoning from dental amalgam does affect the mind and emotions.
Psychol Rep 1994 Feb;74(1):67-80
Psychometric evidence that mercury from silver dental fillings may be an etiological factor in depression, excessive anger, and anxiety.
Siblerud RL, Motl J, Kienholz E.
Rocky Mountain Research Institute, Inc., Fort Collins, CO 80524.
Scores on the Beck Depression Inventory were compared for 25 women who had silver dental fillings (amalgams) and for 23 women without amalgams. Women with amalgams had significantly higher scores and reported more symptoms of fatigue and insomnia. Anger scores from the State-Trait Anger Expression Inventory showed that the women with amalgams had statistically significantly higher mean scores on expressing anger without provocation and experiencing more intense angry feelings. The women without amalgams scored significantly higher on controlling anger, which suggested they invested more energy in monitoring and preventing the experience and expression of anger. Anxiety scores from the State-Trait Anxiety Inventory showed the women with amalgams scored significantly less pleasant, satisfied, happy, secure, and steady, and had a more difficult time making decisions. They had significantly higher Trait Anxiety scores. The women with amalgams also had significantly higher levels of mercury in the oral cavity before and after chewing gum. The study suggests that amalgam mercury may be an etiological factor in depression, excessive anger, and anxiety because mercury can produce such symptoms perhaps by affecting the neurotransmitters in the brain.
Psychol Rep 1992 Jun;70(3 Pt 2):1139-51
A comparison of mental health of multiple sclerosis patients with silver/mercury dental fillings and those with fillings removed.
Siblerud RL.
Rocky Mountain Research Institute, Inc., Colorado.
In this study was compared the mental health status of 47 multiple sclerosis patients with silver/mercury tooth fillings (amalgams) to that of 50 patients with their fillings removed. On the Beck Depression Inventory the multiple sclerosis subjects with amalgams suffered significantly more depression while their scores on the State-Trait Anger Expression Inventory indicated the former group also exhibited significantly more anger. On the SCL-90 Revised, subjects with amalgam fillings had significantly more symptoms of depression, hostility, psychotism, and were more obsessive-compulsive than the patients with such fillings removed. On a questionnaire containing 18 mental health symptoms multiple sclerosis subjects with amalgam fillings reported a history of 43% more symptoms than those without amalgam fillings over the past 12 months. These data suggested that the poorer mental health status exhibited by multiple sclerosis subjects with dental amalgam fillings may be associated with mercury toxicity from the amalgam.
FASEB J 1998 Aug;12(11):971-80
Neurobehavioral effects from exposure to dental amalgam Hg(o): new distinctions between recent exposure and Hg body burden.Echeverria D, Aposhian HV, Woods JS, Heyer NJ, Aposhian MM, Bittner AC Jr, Mahurin RK, Cianciola M.
Battelle Centers for Public Health Research and Evaluation, Seattle, Washington 98105, USA.
Potential toxicity from exposure to mercury vapor (Hg(o)) from dental amalgam fillings is the subject of current public health debate in many countries. We evaluated potential central nervous system (CNS) toxicity associated with handling Hg-containing amalgam materials among dental personnel with very low levels of Hg(o) exposure (i.e., urinary Hg <4 microg/l), applying a neurobehavioral test battery to evaluate CNS functions in relation to both recent exposure and Hg body burden. New distinctions between subtle preclinical effects on symptoms, mood, motor function, and cognition were found associated with Hg body burden as compared with those associated with recent exposure. The pattern of results, comparable to findings previously reported among subjects with urinary Hg >50 microg/l, presents convincing new evidence of adverse behavioral effects associated with low Hg(o) exposures within the range of that received by the general population.
Neurotoxicol Teratol 1995 Mar-Apr;17(2):161-8
Behavioral effects of low-level exposure to elemental Hg among dentists.Echeverria D, Heyer NJ, Martin MD, Naleway CA, Woods JS, Bittner AC Jr.
Battelle Center for Public Health Research and Evaluation (CPHRE), Seattle, WA 98105, USA.
Exposure thresholds for health effects associated with elemental mercury (Hg degree) exposure were examined by comparing behavioral test scores of 19 exposed (mean urinary Hg = 36 micrograms/l) with those of 20 unexposed dentists. Thirty-six micrograms Hg/l is 7 times greater than the 5 micrograms Hg/l mean level measured in a national sample of dentists. To improve the distinction between recent and cumulative effects, the study also evaluated porphyrin concentrations in urine, which are correlated with renal Hg content (a measure of cumulative body burden). Subjects provided an on-site spot urine sample, were administered a 1-h assessment consisting of a consent form, the Profile of Mood Scales, a symptom and medical questionnaire, and 6 behavioral tests: digit-span, symbol-digit substitution, simple reaction time, the ability to switch between tasks, vocabulary, and the One Hole Test. Multivariate regression techniques were used to evaluate dose-effects controlling for the effects of age, race, gender and alcohol consumption. A dose-effect was considered statistically significant below a p value of 0.05. Significant urinary Hg dose-effects were found for poor mental concentration, emotional lability, somatosensory irritation, and mood scores. Individual tests evaluating cognitive and motor function changed in the expected directions but were not significantly associated with urinary Hg. However, the pooled sum of rank scores for combinations of tests within domains were significantly associated with urinary Hg, providing evidence of subtle preclinical changes in behavior associated with Hg exposure. Coproporphyrin, one of three urinary porphyrins altered by mercury exposure, was significantly associated with deficits in digit span and simple reaction time.
> Meanwhile, we have a real, tangible disease to be dealt with: dental caries. And we have to make decisions about how to treat it. Dental amalgam, for many years was THE only option in the armamentarium to treat dental caries, and it remains one of the best for it's strength and affordability. I mean, we can't just go extracting everyone's teeth, just because of what dental amalgam MIGHT do. So we have to make decisions, and to most dentists and people, this was the best one! There is no perfect restorative material, otherwise we would be using it, and avoiding amalgam altogether.That begs the question, "Why avoid it, if it causes no harm?" You see, the question is framed in the dental community as one of risk-benefit analysis rather than one of simply assessing the risk. What is becoming clear is that the mercury in amalgam is quite labile in some cases. The quality of an amalgam restoration can only approach theoretical minimal release, but there are a variety of factors which can cause much higher releases. Every time you breathe or swallow, if you have amalgam in your mouth, you are being exposed to mercury. Some people are exquisitely sensitive to mercury, so the idea that there is a safe level of exposure based on population statistics has no bearing on their experience. Consider the following:
Toxicol Lett 1996 Feb;84(2):113-22
Comment in:
Toxicol Lett. 1998 Sep 1;98(1-2):123-7.
Psychological and somatic subjective symptoms as a result of dermatological patch testing with metallic mercury and phenyl mercuric acetate.Marcusson JA.
Department of Dermatology, Huddinge University Hospital, Sweden.
Sixty patients with a history of malaise over the ensuing weeks following the drilling out of old amalgam fillings were included in the study. They were tested epicutaneously weekly (standard procedure) with either 0.5% metallic mercury in petrolatum or 0.01% phenyl mercuric acetate in water, and, on 2 separate occasions, with only saline or petrolatum as a control according to a randomized double-blind protocol. The presence or absence of an allergic patch test response was read on day 3. Two patients showed allergic cutaneous responses towards metallic mercury and 1 to phenyl mercuric acetate. There was a concurrent 7-day self-registration of subjective psychological and somatic symptoms, using a validated visual analogue scale (minor symptom evaluation profile; MSE). In the group analysis it was clearly shown that the patients reacted with subjective symptoms to phenyl mercuric acetate. A reaction to test doses of metallic mercury seems to exist but could only be visualized when a scoring system was elaborated to individually define those subjects with a psychological and somatic response to test doses of mercury. This psychosomatic reactivity, named intolerance, seems to be unrelated to the cutaneous delayed allergic skin response. Thus, it might be possible to identify patients intolerant to small test doses of percutaneously penetrating mercury (previously considered innocuous). These findings may have a bearing on the systemic side-effects attributed to mercury released from amalgam tooth fillings.
Now, the idea that there is a disorder of defined characteristics arising from exposure to mercury in amalgam, sometimes called "amalgam disease", has received some fairly intensive study. Not surprisingly (as I'll explain), most of the results have been negative, instead attributing the complaints of the subjects as somatization, i.e. of psychological rather than physical origin. The problem with this is that the very nature of the issue, that a commonly-experienced low-level exposure to a proven neurotoxin is almost certainly bound to attract the attention of those people who are somatizers. If you allow those people to self-select into the study population, you no longer have a representative population sample. Those with mercury sensitivities will surely be diluted to such an extent that no relationship will be found. Instead, consider the possibility that those with mercury sensitivity have been given reasonable alternative explanations for their symptomatology, such as dysthymia, depression, or chronic fatigue. They already have a plausible explanation, so may no longer seek out alternative viewpoints. I think it is reasonable to consider mercury exposure as a possible factor influencing mood disorders. Perhaps subtle, perhaps profound.
In some places in the world, amalgam disease is taken seriously.
Neuroendocrinol Lett 2002 Oct-Dec;23(5-6):459-82
Removal of dental amalgam and other metal alloys supported by antioxidant therapy alleviates symptoms and improves quality of life in patients with amalgam-associated ill health.
Lindh U, Hudecek R, Danersund A, Eriksson S, Lindvall A.
Department of Oncology, Radiology and Clinical Immunology, Rudbeck Laboratory, SE-751 85 Uppsala, Sweden. Ulf.Lindh@bms.uu.se
OBJECTIVES: The purpose of this study was to evaluate treatment of patients suffering from chronic ill health with a multitude of symptoms associated with metal exposure from dental amalgam and other metal alloys. SETTING AND DESIGN: We included 796 patients in a retrospective study using a questionnaire about symptom changes, changes in quality of life as a consequence of treatment and assessment of care taking. METHODS: Treatment of the patients by removal of offending dental metals and concomitant antioxidant therapy was implemented according to the Uppsala model based on a close co-operation between physicians and dentists. RESULTS: More than 70% of the responders, remaining after exclusion of those who had not begun or completed removal, reported substantial recovery and increased quality of life. Comparison with similar studies showed accordance of the main results. Plasma concentrations of mercury before and after treatment supported the metal exposure to be causative for the ill health. MAIN FINDINGS: Treatment according to the Uppsala model proved to be adequate for more than 70% of the patients. Patients with a high probability to respond successfully to current therapy might be detected by symptom profiles before treatment. CONCLUSIONS: The hypothesis that metal exposure from dental amalgam can cause ill health in a susceptible part of the exposed population was supported. Further research is warranted to develop laboratory tests to support identification of the group of patients responding to current therapy as well as to find out causes of problems in the group with no or negative results.
Moreover, it is entirely possible that the doctors have been looking in the wrong place all along. Mercury can form irreversible covalent bonds with selenium, which is both good and bad. It takes organic mercury out of the picture, but at the price of an esssential trace mineral. Consider:
Environ Res 2001 Dec;87(3):141-6
Dental amalgam and selenium in blood.Hol PJ, Vamnes JS, Gjerdet NR, Eide R, Isrenn R.
Department of Odontology-Dental Biomaterials, University of Bergen, Aarstadveien 17, Bergen, N-5009, Norway.
It has been suggested that selenium (Se) exhibits protective effects against mercury (Hg) toxicity in humans due to formation of a Hg-Se complex bound to selenoprotein P in blood. The aim of the present study was to investigate Se concentrations in persons who had been examined with respect to general health problems associated with dental amalgam fillings. The Se concentrations were determined in whole-blood samples of 80 individuals by hydride generation atomic absorption spectrometry. The subjects comprised two main groups: 21 healthy controls with amalgam fillings and 20 patients who claimed symptoms from existing amalgam fillings. The median concentration of Se in blood (119.2 microg/L) was statistically significantly lower in subjects who claimed symptoms of mercury amalgam illness than in healthy subjects with amalgam (130.3 microg/L). The difference was more evident in individuals with more than 35 amalgam surfaces (P=0.003). Additional control groups without amalgam fillings comprised 19 healthy controls without amalgam experience and 20 subjects who have had amalgam fillings removed due to suspected symptoms associated with amalgam. The Se concentrations in these groups were not different from those with amalgam. It is indicated that persons with ill health self-related to dental amalgam might have a Se metabolism different from that of healthy people.
One of the reasons mercury is toxic is that it disrupts sulphur-bearing molecules, including many enzymes which rely on sulphur-linkages for their three-dimensional structure (and thus their functionality). Just look around this board and see how many people are dealing with sulphur-amino acid issues: S-adenosyl methionine (SAMe), methionine, betaine (indirectly), folate and B-12 supplements (indirectly), homocysteine. Consider the number of people taking supplemental sulphur in the form of MSM (methyl sulphonyl methane) for e.g. joint problems, or dimethyl sulphoxide (DMSO). People consider taking taurine (sulphur-bearing), and I'm forgetting many other examples right now (I'm still foggy from my trip). The point is, I have seen no research linking mercury exposure to disordered sulphur metabolism, but I have seen massive correlation between sulphur metabolism and depression. Stay tuned.
> I was a bit put off by something you said:
>
> >> 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."
>
> Do you really believe this was some evil plot by a dentist to get rid of mercury in the environment?Were I to rewrite that phrase today, I would use "place" instead of "store". I did not mean to suggest environmental concerns in any respect. You're a dentist, right? It just hit me that you are mattdds. You have very exacting protocols on what to do with excess amalgam, right? You wear rubber gloves to protect against even trivial dermal exposure, correct? But you have no problem placing an amalgam on a buccal surface, guaranteeing exposure to cheek skin, right? Or on an occlusal surface, even in bruxists? Doesn't this seem to suggest different standards being applied in these two situations?
>Strange, I figured it was probably just some dentist trying to fix a tooth, rather than some elaborate evil scheme to poison everyone. Occams Razor comes to mind here. Which would be the simpler explanation? I was a bit surprised that you would say this, being the scientifically minded and intelligent person you seem to be. (Most) dentists are just doing their job of trying to restore function in peoples mouths and prevent further disease (with which dental amalgam has unquestionably helped).
I apologize for offending you, but not for making my statement. I have been told that I can be over-the-top in my negative characterizations, but I do believe that my personal feelings came across, non?
Dentists, like any well-schooled people, are indoctrinated to believe what the extablishment has disseminated. Most of the time, that is an admirable and responsible process, guaranteeing a standard of care across the board. In some cases, it flies in the face of the evidence.
Consider the general concept known as GRAS (Generally Recognized As Safe). Basically, it "grandfathers" well-established practices, and exempts them from focussed inquiry into adverse affects of their use. I would ask you this: "If mercury amalgams were being proposed today as an innovative restorative material for dental caries, do you think that they would get past the regulatory approval process in existence today?" I can guarantee you, they would not get past the committee stage, let alone get into animal trials.
>Saying this seems somewhat irresponsible to me, because people here value your opinions, and they might draw conclusions based on what you say (perhaps making them want to avoid the dentist altogether).
I would hate to think that my statement would have that effect.
I am a human being, full of opinions, all of which are unabashedly biased. Just for the record, I ascribe to an AA aphorism, "Opinions are like assholes. Everybody's got one, and they all stink."
> I am not married to any of the ideas promoted by the ADA, WHO or AMA, but I do feel that whoever makes the claim that dental amalgam is causing depression, multiple sclerosis, etc. bears a tremendous amount of burden to provide evidence for this. The ADA had nothing to gain from their numerous studies on amalgam (all of which failed to show associations between systemic disease and amalgam fillings).I must declare that I categorically oppose that viewpoint. Given the proclivity of the American culture to sue (that was not intended to slight Americans, but I don't think anyone would really deny that), do you really think that the dental establishment has nothing to gain?
> I see using dental amalgam in dentistry somewhat akin to using Lithium or SSRI's in psychiatry. Although we whine that there is no perfect "silver" bullet in psychiatry, we use the best tools that we have, and we make calculated risk to benefit analyses. There are very tangible risks of using some psychiatric drugs, like the MAOI's, TCA's, benzos, and mood stabilizers. But we feel the benefits outweigh the risks. This is the same thing with dental amalgam, but I feel the risks are even smaller and the benefits are great.
>
> Am I making sense here?
>
> Respectfully,
>
> MattRespect returned.
Lar
Random extras:
Toxicology 1995 Mar 31;97(1-3):19-22
The dental amalgam mercury controversy--inorganic mercury and the CNS; genetic linkage of mercury and antibiotic resistances in intestinal bacteria.
Lorscheider FL, Vimy MJ, Summers AO, Zwiers H.
Department of Medical Physiology, Faculty of Medicine, University of Calgary, Alberta, Canada.
Mercury (Hg) vapor exposure from dental amalgam has been demonstrated to exceed the sum of all other exposure sources. Therefore the effects of inorganic Hg exposure upon cell function in the brain and in the intestinal bacteria have recently been examined. In rats we demonstrate that ADP-ribosylation of tubulin and actin brain proteins is markedly inhibited, and that ionic Hg can thus alter a neurochemical reaction involved with maintaining neuron membrane structure. In monkeys we show that Hg, specifically from amalgam, will enrich the intestinal flora with Hg-resistant bacterial species which in turn also become resistant to antibiotics.
Biometals 1999 Sep;12(3):227-31
Dental amalgam mercury exposure in rats.
Galic N, Prpic-Mehicic G, Prester L, Blanusa M, Krnic Z, Ferencic Z.
Department of Dental Pathology, School of Dentistry, Zagreb, Croatia.
The aim of this study was to measure the distribution of mercury, in tissues of rats exposed to amalgam over a two months period. Possible interaction of mercury with copper and zinc in organs was also evaluated. Rats were either exposed to mercury from 4 dental amalgams, or fed the diet containing powdered amalgam during two months. Mercury was measured in the kidney, liver and brain, copper in kidney and brain and zinc in kidney. The results showed significantly higher concentrations of mercury in the kidneys and the brains of rats in both exposed groups compared to control. Even after two months of exposure to mercury brain mercury concentration in rats with amalgam fillings was 8 times higher than in the control and 2 times higher than in rats exposed to amalgam supplemented diet. The highest mercury concentration in the latter group was found in the kidneys and it was 5 times higher than in the control group. We found no significant differences between mercury levels in exposed and control rat's liver. Exposure to mercury from dental amalgams did not alter the concentrations of copper and zinc in the tissues. Histopathological analyses of rats tissues did not show any pathological changes. These results support previously proposed nose-brain transport of mercury released from dental amalgam fillings.
Biol Trace Elem Res 1997 Feb;56(2):143-52
Mercury from maternal "silver" tooth fillings in sheep and human breast milk. A source of neonatal exposure.
Vimy MJ, Hooper DE, King WW, Lorscheider FL.
Department of Medicine, Faculty of Medicine, University of Calgary, Alberta, Canada.
Neonatal uptake of mercury (Hg) from milk was examined in a pregnant sheep model, where radioactive mercury (Hg203)/silver tooth fillings (amalgam) were newly placed. A crossover experimental design was used in which lactating ewes nursed foster lambs. In a parallel study, the relationship between dental history and breast milk concentration of Hg was also examined in 33 lactating women. Results from the animal studies showed that, during pregnancy, a primary fetal site of amalgam Hg concentration is the liver, and, after delivery, the neonatal lamb kidney receives additional amalgam Hg from mother's milk. In lactating women with aged amalgam fillings, increased Hg excretion in breast milk and urine correlated with the number of fillings or Hg vapor concentration levels in mouth air. It was concluded that Hg originating from maternal amalgam tooth fillings transfers across the placenta to the fetus, across the mammary gland into milk ingested by the newborn, and ultimately into neonatal body tissues. Comparisons are made to the U. S. minimal risk level recently established for adult Hg exposure. These findings suggest that placement and removal of "silver" tooth fillings in pregnant and lactating humans will subject the fetus and neonate to unnecessary risk of Hg exposure.
FASEB J 1990 Nov;4(14):3256-60
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.
Am J Physiol 1990 Apr;258(4 Pt 2):R939-45
Maternal-fetal distribution of mercury (203Hg) released from dental amalgam fillings.
Vimy MJ, Takahashi Y, Lorscheider FL.
Department of Medicine, Faculty of Medicine, University of Calgary, Alberta, Canada.
In humans, the continuous release of Hg vapor from dental amalgam tooth restorations is markedly increased for prolonged periods after chewing. The present study establishes a time-course distribution for amalgam Hg in body tissues of adult and fetal sheep. Under general anesthesia, five pregnant ewes had twelve occlusal amalgam fillings containing radioactive 203Hg placed in teeth at 112 days gestation. Blood, amniotic fluid, feces, and urine specimens were collected at 1- to 3-day intervals for 16 days. From days 16-140 after amalgam placement (16-41 days for fetal lambs), tissue specimens were analyzed for radioactivity, and total Hg concentrations were calculated. Results demonstrate that Hg from dental amalgam will appear in maternal and fetal blood and amniotic fluid within 2 days after placement of amalgam tooth restorations. Excretion of some of this Hg will also commence within 2 days. All tissues examined displayed Hg accumulation. Highest concentrations of Hg from amalgam in the adult occurred in kidney and liver, whereas in the fetus the highest amalgam Hg concentrations appeared in liver and pituitary gland. The placenta progressively concentrated Hg as gestation advanced to term, and milk concentration of amalgam Hg postpartum provides a potential source of Hg exposure to the newborn. It is concluded that accumulation of amalgam Hg progresses in maternal and fetal tissues to a steady state with advancing gestation and is maintained. Dental amalgam usage as a tooth restorative material in pregnant women and children should be reconsidered.
poster:Larry Hoover
thread:223248
URL: http://www.dr-bob.org/babble/20030505/msgs/225085.html