Heart & Circulation Immune System/Allergies Birth Defects Infertility Kidney Brain-Neurological-Psychological Antibiotic Resistance
Amalgam, Scientific Facts was first written in 1993 by Dr. G. Munro-Hall. Over the years interesting and relevant data has been added. Time has only reinforced the original message about the damage mercury amalgam fillings can do to health.
Mercury in Dental Amalgam was written in 1993 by Dr. David Kennedy.
These documents are an authoritative and
comprehensive overview of the subject, with scientific references to back them
The science has never been challenged because it is true.
an Amalgam Filling
( Hg )
White Blood cell
Killed by Mercury
This internet site will show you the consequences of Mercury getting in your brain
Everything that was written then is still true now. In fact there is a lot more science available now about the health devastations wrought by amalgam and mercury especially in connection with Alzheimer's and Autism. We keep up to date with the research but it would take volumes to put it all here and would be unmanageable. If scientific fact is your guide rather than opinion then there is enough for you here.
Graeme Munro-Hall B.D.S. F.I.A.O.M.T.
Amalgam, Scientific Facts
(Mercury Dental Implants.)
Scientific Facts for your evaluation:
If you have amalgam fillings in your mouth, you are playing Russian Roulette with your health. You may have no problems whatsoever with the toxicity of the filling material or you may suffer serious health damage.
The symptoms of toxicity can appear within days or 30 years later. The connection between the amalgam filling and the disease symptom is often missed, mainly because it is never looked for.
Amalgam contains 53% inorganic mercury. This should not be confused with organic mercury as found in food. The two are entirely separate though very often this is not understood. There is more mercury in your body from amalgam fillings, if you have them, than from every other source combined. (1)
Mercury is constantly being released from amalgam 24 hours a day (2) . It is released as vapour and swallowed as droplets. Every time you chew, have a hot drink or brush your teeth the amount of mercury released is dramatically increased (3).
The mercury vapour is absorbed through the lungs and within seconds deposited in the brain, heart, kidneys as well as all the other organs (4). The level of mercury in the brain is reduced by half every 27 years (5).
Mercury also travels along the nerves from amalgam filled teeth directly to the brain (6).
If you have other metals in your mouth such as metal crowns, gold fillings or a denture then due to the battery effect (electro-chemical corrosion) the quantity of mercury being released is at least doubled (7).
Mercury from amalgam fillings is preferentially absorbed by the foetus and is concentrated in maternal milk (8). It is indicated by reduced intelligence, learning difficulties and behavioural problems after birth (9). For this reason we strongly recommend that all women of child bearing age have their amalgams removed.
The important questions are - how much mercury comes off and will I be affected by it?
It is important to realise that there is no threshold limit for mercury. It causes damage at even very small concentrations (10).
The International MAK recommended limit (Maximum Arbeits Koncentration) is 50 mcg/m3. Nearly all of our patients test well above this limit.
Remember that the MAK limit is for workers on an 8 hour day, you as an amalgam wearer are exposed to mercury 24 hours a day.
Whether you will, as an individual, be affected cannot as yet be shown. However, if you are in a risk group the chances of you being affected are significantly raised.
Risk groups are those who suffer from or have a family history of:
ALLERGIES; MULTILPE SCLEROSIS; PARKINSONS; KIDNEY DISEASE; ALZHEIMERS; MOTOR NEURONE DISEASE; HIGH BLOOD PRESSURE; CORONARY ARTERY INSUFFICIENCY; INFERTILITY (male & female); NEURO and PSYCHOLOGICAL DISTURBANCES; DIABETES.
Heart and Circulation.
Mercury has a pathological affect on heart muscle, blood vessels, blood pressure, electro-conductivity of the nerves and the endocrine system that control the heart. There are many studies showing these effects, we have chosen just a few.
The gamma 2 free amalgams that are currently recommended by the German Ministry of Health are very high in copper. Copper too has a pathological effect on the heart. Here we will concentrate on Mercury.
Mercury in low doses causes High Blood Pressure (11). High Blood Pressure is extremely common in western society and regarded as life threatening if left untreated. Certainly those with High Blood Pressure should consider whether they want to continue taking a drug which reduces the symptom but leaves the underlying cause untreated.
Heart Muscle Tissue damage.
The damage mercury causes to heart muscle is as a result of displacing Calcium from the normal sites. It reduces heart muscle function, in time this damage becomes permanent. Inflammation and fatty degeneration are seen (12).
Mercury also causes thickening of the arteries and clot formation in the blood vessels (13). Blood coagulation or "stickiness" increases (14). This has a direct correlation with heart attacks.
This is particularly true of coronary arteries (15). When you realise that heart attacks are caused by thickening of the arteries and clot formation in blood vessels and that in 1991 there were 270,000 heart attacks in Germany and 74100 people died you understand how serious the situation is.
Mercury is absorbed preferentially into the pituitary gland in the brain (16).
It alters the production of Pituitrin from the gland, which constricts the coronary arteries (17).
Mercury impairs cardiac electrical function (18). This causes an interruption of the cardiac electrical pattern. Disturbances of the regulatory mechanism of the heart seldom have a positive benefit to the patient!
A comparison between patients with and without amalgam fillings showed that patients with amalgam had:
Significantly higher blood pressure, lower heart rate, lower haemoglobin levels, lower number of red blood cells, greater number of chest pains, tachycardia (rapid heart beat), anaemia and fatigue (19).
Immune System Deficiencies.
Mercury reduces the efficiency of the immune system. This is a toxic effect of mercury. The efficiency of the white blood cells are reduced by decreasing their numbers when exposed to mercury, and the mechanism which white blood cells attack bacteria is inhibited (20). Antinuclear antibodies are formed so the immune system appears to attack itself. The chromosomes in the white blood cells break up and form genetic aberrations (21). The primary humoral antibody response is also suppressed (22).
The consequence of all of his is to reduce your effectiveness in fighting infections, to allow the possibility of auto-immune diseases to appear, and to give you many different kinds of allergies .
Recent research has discovered that because mercury is used as a preservative in the vaccines we give our children, it makes their immune system sensitive to mercury. When an amalgam filling is implanted and constantly releases mercury into the body, the immune system is then activated to destroy the mercury. Unfortunately because mercury is a metal the immune system cannot destroy it, so instead it attacks the cells in which the mercury is deposited. This is the body attacking itself - "Auto-Immune Disease", such as Multiple Sclerosis, Parkinsons, Motor Neurone, etc. A test has been developed and patented called the Melisa Test to identify these sensitized patients. Are you one of them? It is not yet freely available (23).
Aids sufferers have a reduced selenium level in the blood (24), selenium is essential for proper functioning of the immune system. Mercury binds to selenium and prevents its working in the body thereby increasing the risk of a catastrophic breakdown of the immune system. In addition mercury causes a reduction in the number of T-cells, the first line of defence in aids.
Wearers of mercury implants are also exposed to an increased risk of Allergies. Amongst these are Eczematous Dermatitis (25) , Contact Dermatitis (26) , Atrophic Dermatitis (27) , Generalised Allergic Reactions (28) and many others including Lichen Planus. Lichen Planus is a proven cancer risk (29).
Brand new research shows that even by extremely low levels of mercury compounds, the activity of the human immune system is decreased (30). The risk of an allergic response increases with the number of fillings and with their age (31). Between 5 and 30% of amalgam wearers show allergic responses. New data to be published in 1993 shows even these figures to be too low.
Mercury from a mothers amalgam fillings has a pathological effect on the development of her foetus and if the baby is breast fed, the baby after it is born as well.
It takes two days for the mercury from a newly placed amalgam filling to be deposited in the foetus. Maternal milk concentrates the mercury so its level is 4 to 8 times higher than in the blood (32).
Mercury passes through the placenta unhindered (33). One function of the placenta is to prevent toxic material from the mother injuring the foetus. Mercury is so biologically active that the placenta presents no barrier to it. Mercury and Cadmium were found to be factors in reducing foetal nutrition to a degree that death, congenital abnormalities or growth retardation in the baby were possible (34). This work was confirmed by other research (35). Mercury vapour, as given off by amalgam fillings, is absorbed up to 50 times more in the foetus than any other form of mercury (36). Also inorganic mercury i.e. from amalgams, was 12 times more likely to go through a placenta than organic mercury from food (37). Indeed mercury from food like fish does not increase the foetal mercury level (38). This means that the developing baby absorbs more mercury from its mothers amalgam fillings, better called mercury implants, than from anywhere else.
Alcohol increases the absorption of mercury vapour depositing the mercury in the mothers thyroid and in the thyroid and liver of the foetus (39). This means that mothers who drink alcohol during pregnancy increase the amount of mercury deposited in the unborn child from their own amalgam fillings.
So it is clear that mercury from amalgam is deposited in the foetus, but how much damage does it cause?
During pregnancy the levels of mercury in the mother rises by nearly 50%. The number of still births as well as birth defects have a direct correlation to the level of mercury (40). This effect has been known for some time (41).
Mercury also damages the blood brain barrier (42). It can even enter the brain directly from amalgam by-passing the blood brain barrier and infiltrating the nerve cells (43). This means that the brain is prevented from absorbing the vital nutrients needed for full and proper development. Very small amounts of mercury, less than one part per million, cause this effect (44). The enormous consequences of this will be made clear.
Low doses of mercury cause reduced learning capacity in direct relation to the mercury dose. The higher the amount of mercury absorbed, the more the learning capacity was reduced. The mother with an average number of amalgam fillings absorbs more mercury into her and her babies body on a daily basis than was used in these experiments. These results were confirmed by two animal experiments and the changes were permanent (45). The research subjects exhibited marked hyperactive behaviour.
Mercury reduces the intelligence of the child, the higher the mercury level, the lower the intelligence (46). It gets worse, lead and mercury act synergistically, this means that together they have a greater effect than the same levels do alone. Lead also reduces intelligence and is present in our environment.
Mercury from amalgam fillings of the mother can decrease a childs intelligence, reduce his or her learning capacity and make them hyperactive.
As mercury is absorbed into the brain and central nervous system throughout the development of the baby this can result in functional disturbances and behavioural alterations later in life (47).
Statistics show us that 2 to 3% of children have defects that are seen within the first year of life (48). 16% have physical or mental defects that only become apparent later in life. Abolition of mercury implant fillings should reduce these high numbers
Mercury can reduce both female and male fertility rates quite dramatically. Couples experiencing difficulties in conception should read the next section carefully.
A study of dental nurses showed them to have a fertility rate only 50% of normal if they worked for a dentist who used amalgam (50).
Spontaneous abortion is three times higher in female dentists than normal, not only that, they have more difficult labour and higher death rate after giving birth (51). The same result has been seen in many animal experiments after exposing the animals to mercury. Monkey experiments show that mercury reduced the number of live births but caused no overt signs of toxicity (52).
Other animal studies clearly demonstrated not just reduced fertility rates but that 26% of babies died compared to 1% of controls after exposing the pregnant animals to mercury. To put it unequivocally, the mothers exposed to mercury appeared entirely normal but more of their babies were born dead.
Disturbances in the menstrual cycle naturally will alter the fertility rate. Exposure to mercury caused hypermenorrhoea, excessive blood flow, irregular intervals and painful menstruation (53). The longer the time of exposure to mercury the greater the chance of a problem. The rate of anovulation, or failure to produce a viable egg, is nearly doubled in those exposed to mercury compared to a control group (54).
Another fertility problem is the action of mercury on the thyroid. We have seen that mercury is preferentially absorbed by the thyroid, it depresses thyroid function (55). In time the damage to the thyroid becomes irreversible. Thyroxine from the maternal thyroid is vital for the brain and nerve development of the baby (56).
Endometriosis is thought to be an auto-immune disease brought on by a disturbance of the immune system (56). We have previously described how mercury alters the immune system. Endometriosis is a common cause of infertility, up to 40% of all infertility is put down to this disease (57). Due to the action of mercury on the pituitary, adrenal glands and progesterone production and the responsiveness of these glands to hormonal stimulation (59) mercury from amalgam fillings is regarded as a significant factor in endometriosis (60).
It is best to avoid replacement of amalgam fillings during pregnancy as removal of amalgam may increase the amount of mercury in the body. Alcohol should also be avoided.
It is important to remember that the foetus throughout the whole time of its development is exposed to mercury from the mothers amalgam fillings.
We recommend that all women of child bearing age have their amalgam fillings removed under Hall V-Tox protocols and replaced with non-metal alternatives. Furthermore they should undergo nutritional detoxification and other non-invasive procedures as described by the IAOMT.
Over 50% of infertility problems are caused by a fault in the male sperm. The fertility of men is significantly altered by mercury. Mercuric compounds were marketed in England from 1938 as a spermicide, or substance that kills sperm (61). It was very effective.
Heavy metals including mercury, gold, aluminium and vanadium have been found in high concentrations in sperm (62).
The motility and the speed of the sperm is reduced by mercury compounds (63) .
A man is considered sterile if 25% of his sperm is abnormal.
Mercury inhibits the manufacture of DNA in the sperm (64), DNA is the carrier of genetic information. RNA synthesis is also inhibited (65). The function of both DNA and RNA are complex to say the very least but the alteration of the manufacture of these genetic messengers by mercury is likely to mean reduced male fertility. Animal experiments have confirmed this (66).
Selenium is absorbed into the sperm (67). Indeed it is so important to the sperm that if selenium is in short supply in the body, the testes get priority for existing supplies (68). Mercury also is stored in the testes where it readily combines with the selenium thereby reducing the amount available for healthy sperm production.
Accidental industrial exposure to mercury over an eight hour period caused impotence lasting many years (69). This does not mean mercury from amalgam can have a similar effect but just to show what a powerful long term effect a small exposure to mercury can have on the male reproductive organs.
We recommend that men trying to become fathers have their mercury fillings replaced with non-metal alternatives under Hall V-Tox amalgam removal protocols. Furthermore they should undergo nutritional detoxification and other non-invasive procedures as described by Hall V-Tox.
The connection between mercury and pathology of the kidney have long been established. The German Ministry of Health have recommended in early 1992 that no patient with an existing kidney malfunction or disease have new amalgam fillings placed in their teeth. However, it must be remembered that if 10% of only one kidney functions, then that is enough to maintain life. This means that kidneys can be severely damaged before any symptoms present themselves to the amalgam wearer.
Even when the problem arises does the patient or the medical doctor ever consider the constant release of mercury from amalgam fillings as a possible cause of the kidney disease? Very unlikely at present. There have been experiments on a variety of animals that show measurable kidney damage can be present even though the animals appear outwardly healthy (70). Damaged kidneys do not excrete mercury efficiently, the level of mercury in the urine appears low. This means the level of mercury in the urine can mislead the doctor into believing mercury is not the problem.
Kidneys preferentially absorb mercury. This means that when inorganic mercury from dental amalgam enters the body one of the first parts of the body to absorb it are the kidneys (71).
Mercury damage to the kidney in man (72) (73) and in animals (74) (75) is well known and has long been documented. Dentists and their assistants are among the first to show damage (76).
Chronic exposure to mercury changes the way the kidney excretes and manufactures its own proteins which in turns leads to a nephritic syndrome which alters the course of infections (77( (78). This is extremely serious.
Scientists have discovered that placing amalgam fillings in sheep and monkeys reduced the Glomular Filtration rate by 50% after 31 days (79). The main function of the kidney is to filter the blood, so amalgam reduces the main kidney function by 50%. At the same time the potassium-sodium pump was reduced by half. This has now been confirmed by human experiments (80). Correct levels of potassium and sodium are vital for body function and the imbalance of these elements can lead to heart attacks (81).
Mercury damages the kidney in a variety of ways. It blocks the tubules and physically prevents them working. It reacts with the kidney, producing stress proteins and preventing the body making the necessary proteins (82). At worst the bodies own memory cells from the immune system react to the mercury deposited in the kidney by slowly destroying the kidney (83).
Kidney disease is increasing in western Europe at the rate of over 10% per year for no known reason. The economic and personal costs to society and the individual are enormous. The discontinued use of dental amalgam and its replacement under correct conditions should have a profound effect on this problem.
If you have a kidney problem or a family history of kidney problems , you should have your amalgams replaced under strict IAOMT protocols for your future health.
The brain is another target organ for mercury, the more amalgam fillings you have, the more mercury is being daily deposited in your brain (84).
Dentists who have more exposure to mercury by removing and placing amalgam fillings than the average person, have twice as much as mercury in their brains than average. It is concentrated in the pituitary gland in particular (85). Dentists and their assistants have also twice the brain cancer rates than is considered normal.
Mercury travels to the brain in a number of ways. It travels directly from the amalgam filling through the tooth along the nerve and directly into the brain (86). The mercury vapour given off from amalgam fillings is absorbed into the blood from the lungs and is then within seconds deposited in the brain. The half life for mercury in other parts of the body is 70 to 120 days however in the brain it is 10.000 days. This means after 10.000 days or 27 years after a single dose of mercury only half of it has gone (87). After another 27 years another half will have gone still leaving one quarter of the original dose left. Amalgam wearers are absorbing mercury daily from their fillings so the amount of mercury in the brain will continually increase as long as the amalgams are there.
The effect of mercury on the developing brain of a baby has been previously discussed, learning difficulties etc.
The blood brain barrier is the protective shield that protects the brain from from substances in the blood that can harm the brain. Mercury alters this barrier reducing its protective function (88).
For more information, click here.
Mercury and Alzheimers.
20% of the population in England over 80 years old have Alzheimers. This disease was first described in 1907, it is a new disease. High levels of mercury are deposited in Alzheimers brains, the levels of mercury being more out of balance than any other trace element (89). Rats given mercury shows the same irreversible changes in their brains as happens in human brains (90). Amalgam is considered a likely source of this damaging mercury (91). This is an ongoing research project.
A successful way of helping Alzheimers victims is to give them acetyl-L- carntine, a compound made in the body. The body needs methionine to make carntine and mercury reduces the amount of methionine available to the body (92), all the research neatly fits together.
Studies have connected Parkinsons disease, also a new disease, with mercury, with the higher the dose the more likely you are to get the disease (93).
There is a long connection between Multiple Sclerosis and mercury. It is enough to say here that research is continuing and to date the proper removal of amalgam fillings has resulted in a 76% rate of cure or improvement (94).
There have been several anecdotal cases of amalgam removal eliminating epilepsy. Research has connected reduced levels of Taurine, a compound made by the body, with epilepsy (95). Mercury (96) massively reduces the amount of taurine made by the body and it appears that prenatal mercury from a mothers amalgam fillings can make this effect permanent. There are other studies that connect mercury to epilepsy using a different biochemical pathway. Reduced taurine also increases the risk of heart disease (97).
Psychosis and other effects.
In this area that has been much mis-diagnosis due to the fact that the medical doctors were unaware of the release of mercury from a patients fillings. Psychiatric disturbances have been seen in children of 12 years old due to mercury (98).
Anxiety and depression have been reduced by selenium, the symptoms coming back when the selenium supplement was stopped (99). The supplementation of selenium reduces the amount of mercury available in the body, so as the body levels of mercury fell, so did the level of symptoms. The lower the levels of selenium, the more anxiety and depression were felt.
Patients with mercury in the brain at low chronic so called subtoxic levels, were compared to patients without mercury. The mercury patients had short term memory problems, obsessive compulsion behaviour, anxiety and psychotism were increased (100). Apart from this they were entirely normal!
Permanent neuromuscular changes have been noted on workers exposed to inorganic mercury (101).
Common misdiagnoses are neurasthenia, hysteria and schizophrenia (102). Other symptoms include tremor, memory loss, eye problems, mood change, decreased self confidence, increased sweating and sleep disturbances.
In tests, dentists who worked with mercury showed reduced hand co-ordination, concentration and memory when compared to a similar group of people. The longer the dentists had worked with mercury the greater were the effects (103). The average was a 13.9% reduction.
Several reports have connected mercury with increasing the ageing process. It appears that levels of mercury lower than that which are known to cause central nervous system toxicity cause biological change in the brain associated with accelerated ageing (104).
The effects of mercury on the brain are many and often go unrecognised and untreated. They are subtle and often irreversible
Antibiotic Resistance and Amalgam.
According to antibiotic expert Dr Neu of Columbia University, that despite over 150 antibiotics available patients are dying of infections that were considered harmless only a few years ago. The bacteria are becoming antibiotic resistant. Good examples are Salmonella and Tuberculosis. It seems that the bacteria that are resistant to antibiotics can exchange genetic material with their neighbours so that they too can become antibiotic resistant and survive. How did this recent change come about?
Mercury from amalgam fillings placed in the teeth is transported to the gut. Mercury is so toxic that it can kill most bacteria. Those bacteria that are resistant to mercury are also resistant to antibiotics. The research has been carried out in sheep, monkeys and now in humans. When the amalgams are taken out, the bacteria lose their mercury and antibiotic resistance (105). This is very significant and can have a major impact on your health.
It must be stressed that there is no guarantee that removing amalgam will prevent or cure any illness. Any improvement that does take place may be immediate or take many months. It all depends on individual susceptibility related to the dose of mercury and other toxic materials and the type of detoxification procedure followed.
by Graeme Munro-Hall BDS., FIAOMT
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100. Uzell B.P. Chronic low level mercury exposure and neuropsy. functioning. J. of Clinical and Experimental Neuropsyc. 8(5) 581-593. 1986.
101. Miller J.M. Subclinical psychomotor and neuromuscular changes in workers exposed to inorganic mercury. Ind. Hyg. Assoc. J. 36. 725-33 1975.
102. Hansen M. Effects of mercury on the nervous system. Bioprobe Marvh 1988.
103. Ngim.C.H. Chronic neurobehavioral aspects of elemental mercury in dentists. Brit J. of Ind. Med. 49. 782-90. 1992.
104. Brooks N. In vito evidence for the role of glutamate in the CNS toxicity of mercury. Toxicology. 76. 245-6. 1992.
105. Summers A.O. Increased mercury resistance after mercury fillings. The Physiologist. Aug 15th 1990.
International Academy of Oral Medicine and Toxicology. Dr David Kennedy DDS FIAOMT
Theme: MERCURY IN DENTAL AMALGAM.
Many materials commonly used in dentistry today are considered toxic and harmful to our health. Among those materials are the base metals mercury, nickel, lead, chromium, #cobalt, beryllium, zinc, tin, copper, and many others. We also apply sterilizing agents such as phenol, formelcresol and chlorine directly into root canals. All of the phenols and most of the halogens are considered toxic to some degree.
This profession has a long history with regard to the use of mercury. Although the focus of this presentation is on the heavy metal mercury, the concepts applied can be readily transferred to most of the other materials. A recent Louis Harris poll reported that a clean environment is second only to a happy home life among the desires of adults. It is our responsibility to protect ourselves and our staff as well as our patients from exposure to toxic materials.
Most of the technology used by scientists today to uncover hidden environmental hazards was not available even ten years ago. Numerous new illnesses have cropped up from unknown causes, among which environmental exposure to toxics seems to be a most likely suspect. As these investigations continue you can expect to find that many of the most common dental materials will no longer be considered appropriate for use due to their potentially toxic nature.
Modern technology has focused on developing techniques for evaluating biocompatibility that look for minimal damage rather than gross disease. But in the telling words of astronomer Carl Sagan, "Absence of evidence is not evidence of absence."
In this paper I will review the state of the research on the patient's exposure to mercury from dental fillings, the occupational hazards of dentistry, the environmental impact, and how best to protect ourselves, our patients, and our staff from injury. This subject has been a source of controversy for over a century. The reason the argument has lasted so long is because investigators did not rely upon the documented scientific literature. Through the use of modern science we can dispel many of the common myths about dental amalgam.
The Chemistry of Mercury.
Mercury is an unusual base metal which is molten at room temperature. It is highly volatile and vaporizes readily. The fumes from elemental mercury are uncharged atoms (Hg0) that are easily (75% to 100%) absorbed from lung and nasal tissues (1). Once absorbed, this uncharged form may enter the bloodstream and penetrate cell membranes, the blood-brain barrier, the placental membrane, and fetal tissues(2).
Mercury combines readily with many compounds, and it has a particular affinity for sulfur. When it attaches to protein molecules, it alters their tertiary structure. This is one way it exerts its poisonous effects. Regardless of the source, once mercury enters the body, the body tries to detoxify the poison. The process of detoxification involves the production of mercurous or mercuric (Hg+ and Hg++) forms which are not as easily absorbed through cell membranes. Consequently, the biological removal of mercury form tissue is inhibited.
Neurological tissues have a high sulfur content. For this reason, mercury tends to accumulate in the central nervous system(3). Less than 1 ppm of mercury absorbed into the bloodstream can impair the blood-brain barrier within hours, permitting substances from the plasma that would normally be excluded to enter into the cerebral spinal fluid(4,5). All mercury compounds appear to cause the same kind of damage in the brain(6,7,8). Other organs and systems adversely affected by mercury are the immune system, kidneys, liver, and the reproductive and cardiovascular systems(9,10).
How Does It Poison?
Because of mercury's effects on the central nervous system, many divergent neurological and psychological symptoms are common findings in mercury poisoning. In 1926 the famous German scientist Dr. Alfred Stock meticulously cataloged and classified these symptoms through conducting experiments on himself. He identified confusion, memory loss, and irritability as associated with inhaling a single 10 ppm dose of mercury. He termed these symptoms micro-mercurialism.(11). Mercury is also associated with depression, suicidal thoughts, nervousness, fits of anger, shyness, and emotional outbursts.
In addition to the psychological symptoms associated with exposure to low doses of mercury, the immune system appears particularly sensitive to this toxin as well. It responds to mercury with an antigen/antibody reaction in an attempt to remove the foreign substance. Two types of white blood cells are involved. T-cells are endowed with special qualities that allow them to migrate to sites of infection and defend against invading microorganisms, viruses, and toxins. B-cells produce antibodies specific for the unwanted invader or foreign substance, which circulate in the plasma.
The immune system's response works like this. When T-cells recognize the presence of an antigen, they stimulate the B-cells (memory cells) to produce antibodies to the antigen. The B-cells, along with a special class of T-cells called helper cells, then surround and engulf the antigen and neutralize it. Once the job is complete, other T-cells (suppressors) suppress further production of antibodies. The used-up B-cells, along with the antibodies and toxins or dead germs, are excreted through the kidneys and feces. An allergic reaction is similar, except that the B-cell antibodies also cause a release of histamines. Histamines are what causes the tissue breakdown and red skin reaction.
White blood cells are very sensitive to mercury exposure and as a result, their numbers at first increase and later, as they die, the numbers will decrease. Other toxic effects on the white blood cells also result from exposure to mercury. Release of the migratory inhibitory factor appears reduced, and antinuclear antibodies are formed, so that the immune system appears to attack itself. And the respiratory burst of the white blood cells (the mechanism by which white blood cells attack bacterial invaders) is inhibited(12). Exposure to mercury causes the chromosomes of white blood cells to break and form unusual combinations and genetic aberrations(13,14,15). White blood cells from mercury-diseased rats show a significant decrease in ability to replicate their own chromosomes, and 90% of the cells develop autoimmune antibodies for their own nuclei(16,17). Mercury also suppresses the primary humoral antibody response(18,19,20,21,22).
In a preliminary study Dr. David Eggleston demonstrated that both mercury and nickel dental restorations suppress the quantity of circulating T-cells present in humans(23). Vera Stejfkal, M.D. of Sweden has documented the immunological response to mercury in humans. She has even found an adverse reaction in infants inoculated with a mercury preservative. While further research is badly needed in this new area of science, it is clear that mercury plays a very important role in immunosuppression. Its adverse effects on human resistance to diseases and tumors cannot be overlooked.
The endocrine system is also affected by the accumulation of mercury in certain critical tissues. Not only does inhalation of this volatile substance allow transport from the lungs into the bloodstream. In addition, the nasal mucosa can apparently transport it directly to the brain and pituitary. It is here that critical hormone balances can be damaged.
How Toxic Is Mercury Compared to Other Metallic Compounds?
To answer this question, Sharma and associates studied the cytotoxic effects of several compounds on chick ganglia. They stated in their conclusions: Our study showed mercury, cadmium, and lead in decreasing order of toxicity(24).
SEVERELY TOXIC: MOD. TOXIC: SLIGHTLY TOXIC
MERCURY ARSENIC LEAD
CADMIUM THALLIUM SELENIUM
VANDEX-TIN COPPER TIN OXIDE
In order to protect workers from excessive exposure to toxic materials, the governments of all the developed nations and the World Health Organization (WHO) have adopted adult industrial standards for mercury exposure. In addition to these industrial exposure standards, many governments have also enacted legislation called environmental standards, or simply EPA, to protect the general populace from excessive pollution.
Environmental standards are strictly enforced in California, and our state government at the request of the people has placed even more stringent requirements on many emissions than the federal government has. In the United States the U.S. EPA standard is the only nonoccupational standard, and as a result it is the only exposure considered appropriate for the majority of the population.
When looking at the question of toxins in dental restorations, it is reasonable to conclude that restorations should certainly not increase our patients' exposure to levels of toxic materials that exceed the EPA health standards. Beyond that, it should be noted that both the U.S. EPA and WHO have stated that no amount of exposure to mercury can be considered totally harmless, and it is not possible to establish a level at which no response will be seen(25).
Some individuals in society are at higher risk from toxic exposure than others. Such groups include the elderly, pregnant women, women of childbearing age (for possible unsuspected or near future pregnancy), infants, children, the hypersensitive, immunosuppressed, and those already occupationally exposed. The Occupational Safety and Health Act (OSHA) has recommended no exposure of fertile women to amounts of mercury greater than 10 micrograms per cubic meter of air, and pregnant women should be occupationally exposed to no mercury.
Individual Intraoral Exposure.
Although evidence that mercury was leaking from dental fillings was previously discovered in 1926 by the aforementioned Dr. Alfred Stock, and again noted in 1979(26), in 1981 Dr. Carl Svare (27) partly by chance made a rediscovery that shocked the dental community. To conduct a series of experiments on the amount of mercury in expired air, he had asked for volunteers from among his dental students. One woman waiting at the end of the line saw that it would be some time before she was to be tested. So she went across the street the have a pizza for lunch. When she returned, the line was gone and Dr. Svare tested the mercury in her exhaled breath. Her mercury measurement was so high it blew out his equipment.
When he learned that she had just eaten a pizza, he recovered some of the uneaten pizza and could find no mercury contamination. With further experimentation, Dr. Svare noted that the student's mercury vapor level began to drop. He then gave her a piece of rubber tubing and instructed her to chew on it for a while. He was amazed: her mercury level shot right back up. The other students were recalled and remeasured after chewing sugarless gum with similar results. This landmark study became known as the Chewing Gum Study. It led to subsequent findings that mercury release from fillings increases dramatically by 15-fold whenever the fillings are stimulated by chewing, brushing, hot fluids, bruxism, etc. Numerous other investigators have confirmed these results(28,29,30,31,32).
Low doses of mercury are almost completely absorbed from the lungs before exhaling. Therefore, Dr. Svare's exhaled air measurements represent only a small fraction of the dose absorbed by an individual. We also know that personal habits such as night grinding, gum chewing, and mouth breathing can greatly affect the rate of release of mercury from fillings. Because of wide variations in such personal habits, it is not possible with present technology to predict which patients will release the most mercury. But an average daily dose can be estimated.
In 1985 Dr. Murray Vimy, et al. took the examination several steps further by subjecting the chewing to a standardization technique and plotting the increase of mercury release with respect to time(33,34). He discovered that fillings take only 10 minutes to reach maximum output and do not immediately stop releasing when chewing stops, but rather continue for a period of up to 90 minutes. This was termed the "cool down" period.
He then began the extremely complicated process of estimating how much mercury a person might absorb daily from mercury fillings. For the conversion from intraoral air exposure to absorbed intake, consideration was given to such factors as respiratory volume, absorption rate, oral-nasal breathing ratio, frequency and duration of chewing, and cool down period following stimulation. In each instance the lowest possible estimate was chosen to avoid overestimating the risk posed by the release of mercury from fillings. Vimy concluded that by the most conservative estimate, the average person with 12 fillings would absorb approximately 11 micrograms per day from the fillings alone(35,36).
To put this estimate in perspective I have prepared the following graph. It compares the EPA maximum daily dose of mercury from: sources other than air, air alone(i.e. smog), and all sources combined. Note that the EPA standard is based on an adult weight of 165 lb (75 kg). To be applicable to small children, it should be reduced in proportion to their weight.
Insert EPA GRAPH here.
AIR = 20. OTHER = 10. TOTAL = 30MCG/DAY.
The most obvious result of mercury/silver dental implants is an increase in the individual's exposure to mercury. This is demonstrated by elevated blood levels that are measurably higher for those with fillings than those without(37). The following graph shows the findings of three different researchers measuring intraoral mercury vapor.
Insert Intraoral Mercury Vapor Graph here
USA(OSHA) = 100
NIOSH = 50
WHO =25 mcgHg/m3
In his reports, Vimy stressed the concept of "average intake" to allow for the fact that some of the people examined were definitely not average. For example, Dr. Svare's young dental student was well over 100 µg/m3, where the average person was measured at 32 µg/m3.( Thus, the daily intake for this young woman would be 3 times 11 or 33 µg of Hg per day.
Sellers discovered an even more disturbing phenomenon. His experiment involved children aged 11 to 13 with mixed dentition. Of the children with amalgams, Sellers found 33% with intraoral levels above 50 µg/m3.(38). In fact, 47% of the children who had 6 fillings or more tested above 50 µg/m3. Sellers failed to fully appreciate the seriousness of such high exposure levels, however. He commented that "Such concentration may not be any more dangerous than briefly walking through a contaminated workplace --an interpretation revealing an apparent disregard for the safety of children. It is important to keep in mind that the industrial standard is not an environmental standard and was never meant to protect the health of children. Rather, it is clearly a workplace standard meant for consenting adults who work 40 hours a week and are medically monitored. They are presumably paid a salary commensurate with the obvious risks to which they are exposed.
It is the policy of the state of California to destroy school buildings that cannot achieve compliance with our stringent EPA standards. It is unlikely that any informed parents would give their children permission to play in a toxic waste dump 4 to 10 or more hours daily. Should toxic poisons be placed in their mouths instead?
Sellers' study is further flawed since the author terminated chewing after only 4 minutes and therefore did not allow the children to chew for the full 10 minutes necessary to maximally stimulate the fillings. Vimy's previous research had demonstrated that the dramatic increase in output continues to rise for 10 minutes. One can only speculate the levels that would have been achieved had the author allowed the children to reach maximum output. In the United States today many children chew gum all day. It is clear from the discussion that the author failed to recognize the inherent medical, legal, and moral liabilities of exposing the children to such high levels of this toxic material.
Abraham, et al. provided additional information regarding blood levels and the release of mercury from fillings. In their experiment, baseline blood and breath air samples were taken after subjects had not eaten or drunk anything for the previous 12 hours. Then the subjects were required to chew gum for three minutes at 120 beats per minute, followed by postchewing blood and breath air samples.
Subjects with amalgam measured higher both before and after chewing than those without, and there was no change in the no-amalgam group following chewing. Those with amalgam fillings
measured postchewing levels higher than prechewing levels in both blood and breath. Abraham, et al. concluded their report by stating: Given these facts, the small increase in blood mercury levels that is statistically associated with dental amalgam restorations should be a matter of concern for dentists as well as for the recipients of these restorations.(39)
It should again be pointed out here that three minutes of chewing does not correspond to normal chewing and would not have allowed the fillings to reach their maximum output.
Previous studies by Kroncke, et al. and Ott and Kroncke (40,41) had failed to find a connection between blood levels and the number of amalgam fillings, although they did find that those with amalgam had higher blood levels than those without. Their work has not been verified by other investigators, and the preponderance of scientific data suggests that they failed to find correctly. (42) There is also a question about their sampling technique, which may have caused the loss of mercury from their samples. In addition, blood alcohol was not recorded. Alcohol will greatly reduce blood levels and perhaps increase tissue levels. Their experimental group may also have had some additional external exposure to mercury.
Does Dental Amalgam Contribute Significantly to the
One way to evaluate this question is to analyze human autopsy tissues for mercury accumulation. Till sectioned tissues and human jawbone around teeth with and without amalgam fillings and found high levels of mercury around teeth with fillings. Surprisingly he found even greater amounts if a gold crown covered an amalgam. (43)
The biological half-life of mercury in human nervous tissues appears to be over 10,000 days (27 years). (44,45) Since the brain is sensitive to mercury, many of the first symptoms of mercury poisoning are neurological and psychological in nature. The action of mercury on the brain may occur by blocking the metabolism in nerve tissue which frequently causes irreversible damage. (46)
Certain areas in the brain tend to collect much more mercury than others. The pituitary gland which regulates the human hormonal system preferentially collects mercury at a rate 10 times greater than the brain as a whole. (47) It is also well recognized that mercury has an adverse effect on fetal neurological development.
It can be assumed that if mercury is present and the source is amalgam fillings, then autopsy tissue samples taken from individuals with amalgam fillings would contain more mercury than samples from those without fillings. In one of the largest human autopsy studies conducted so far, University of Southern California professor Dr. David Eggleston performed over 100 human brain biopsies and analyzed them for mercury. The results showed a high positive correlation between the amount of mercury in the brain and the size and number of fillings in the mouth. The experiment found a 3- to 4-fold greater occipital lobe brain burden of mercury for those with an average number of fillings than for those without fillings.
These results are also particularly significant because they confirm earlier studies and show unquestionably that dental mercury does escape from fillings, is absorbed, and does contribute significantly to the total body burden of mercury. (48)
The U.S. EPA has established the optimum intake of mercury is 0 µg/day! They have suggested that 30 micrograms is the maximum allowable daily dose of mercury from all sources, with just 10 of these µg allocated to sources other than air. All sources and forms of mercury are considered equal and cumulative.
WHO expert committee calculated that the human daily dose of mercury from various sources is:
Dental amalgam =3.0-17.0 µg/day (Hg vapor)
Fish and seafood = 2.3 µg/day (methylmercury)
Other food = 0.3 µg/day (inorganic Hg)
Air & water = Negligible traces
The WHO also noted that "A specific No-Observed--Effect Level (NOEL) for mercury cannot be established." (49). In other words, because the effects of mercury poisoning are cumulative and long-term, the only definitely safe exposure is no exposure at all.We can now definitely state that as a direct and persistent result of amalgam implants the patient's immune system is altered, gingival tissues and jawbone adjacent to the tooth are saturated with mercury, and the mercury content of the brain increases by three- to fourfold. And as a result of extensive use of this material, silver/mercury fillings are now considered by the World Health Organization to be the predominant source of human exposure. (50,51)
In 1987 an expert committee instructed to review the safety of dental amalgam by the Swedish Socialstyrelsen (Department of Health) concluded that from a toxicological point of view, mercury is too toxic for use as a filling material and dentists should use other materials as soon as they are available. As a first step amalgam work on women who are pregnant should cease because of danger of damage to the brain of the fetus. (52)
Dentists and Personnel Exposure.
While the issue of patient exposure is still the subject of intense investigation, there is no question that dentists are at risk. Let me preface my remarks regarding the urinary excretion of mercury in dental personnel by quoting a short excerpt from from Goldwater, et al.: Urinary mercury levels may give some indication of the degree of exposure. They are of limited value in the diagnosis of poisoning, since high levels can be found in human subjects who are symptom-free, and low levels in those exhibiting marked evidence of mercurialism. It has been suggested that, in some cases, failure to excrete mercury is a factor in the development of poisoning. Those investigators who have studied the subject are in almost unanimous agreement that there is poor correlation between the urinary excretion of mercury and the occurrence of demonstrable evidence of poisoning. (53,54)
Urinary excretion may, however, provide some information on a group basis as to degree of exposure. This has been publicly acknowledged at the National Institute of Dental Research (NIDR) workshop on the biocompatibility of metals in dentistry. (55)
As part of the ADA's Health Assessment Program held at ADA annual sessions in the years 1975 through 1983, the urinary mercury levels of 4,272 U.S. dentists were measured. The mean level was 14.2 micrograms/liter with a range from 0 to 556 micrograms/liter. An increase in the mean mercury level was found to be correlated with increase in age of the office, the practice, and the dentist. The highest mean was found in general dentists, at 15.3 µg/l, and the lowest was found in orthodontists, at 3.9 µg/l. Blood samples of l,555 dentists found that the mean for all dentists was 8.2 ng Hg/ml blood, and the mean for general dentists was 8.8 ng Hg/ml. (56) That is approximately 12 times greater than the mean blood level of 0.7 ng/ml Abraham found for those with fillings. (57)
URINE LEVELS BY OCCUPATION.
In the U.S. the average urine level for the general population is 0 to 5 µg/l, with above 20 µg/l considered abnormal. 4 µg Hg/l is considered excessive in the Federal Republic of Germany. (58) The U.S. Center for Disease Control has published the opinion that 30 µg Hg/l urine is the maximum accepted level. 50 µg/l is associated with load-induced tremors, and 100 µg/l is generally associated with outright tremors. (59) Furthermore, a study by Berlin showed that inhalation of mercury vapor selectively increased the uptake in the brain. (60) The recent animal study by Vimy shows why there is no blood or urine threshold for mercury which can be considered totally safe. In Vimy's sheep study, the blood levels remained low and urine level never exceeded 10 ng Hg/g, yet high levels of mercury were found accumulated in critical organs.(61)
In their report on the Biocompatibility of Metals in Dentistry, the NIDR published the opinion that The distribution of mercury into body tissues is highly variable and appears to be of little correlation between levels in urine, blood, or hair and toxic effects. On the other hand, high urinary output on a group basis may indeed indicate high exposure. If exposure is prolonged, then urinary levels will eventually drop as the kidneys lose their ability to remove mercury from the blood.
In summary, then, since the ADA Health Assessment Program's studies of dentists and dental personnel found urinary output 3 to 15 times that of the general population, (62) there seems to be little question that we are excessively exposed. The following percentages reveal the extent of that overexposure.
19.1% measured over 20 µg/Hg/l (Nationwide equals 29,500 dentists)
10.9% measured over 30 µg/Hg/l (Nationwide equals 16,500 dentists)
4.9% measured over 50 µg/Hg/l (Nationwide equals 7,500 dentists)
1.3% measured over 100 µg/Hg/l (Nationwide equals 2,000 dentists)
For the last 20 years dental offices have been tested for compliance with various industrial standards. In addition, several statistical surveys of our exposure levels have been conducted. Our offices do not fare too well when compared to these safety standards. As you may have noted, the U.S. has one of the highest exposure standards in the world. Despite this, over 10% of our dental offices exceed this standard. A 1983 survey of British dental offices found that 10% of those also violated that country's industrial exposure standard of 50 µg/Hg time-weighted average (TWA). (63)
Many procedures common to the practice of dentistry are known to release mercury vapor. Such routine duties as condensing, polishing, grinding, and mixing amalgam will send an invisible shower of mercury droplets into the air. (64) These droplets may be inhaled or may fall to the floor and vaporize. Dental offices have been studied extensively in the scientific literature to see how the handling of mercury affects the ambient level of mercury vapor found in the workplace. Theoretically, the type of flooring should make a difference. However, this did not seem to be one of the critical factors. (65,66) Research indicates that the process of mixing, packing, drilling, and polishing a mercury/silver filling will expose everyone present to high levels of mercury. (67,68,69,70,71,72,73,74)
Dental Procedures.- over 50 TLV.
Rinsing. Slightly over.
Aspiration. Double over.
Autoclaving. 50 TLV.
Condensing. 1000. ie 20x TLV.
Dry cutting. 2000. i.e. 40x TLV.
In his lecture at Tuffs in Boston, Mass., Dr. Patrick Störtebecker discussed the Direct Transport of Mercury from the Oronasal Cavity to the Cranial Cavity as a Cause of Dental Amalgam Poisoning . (75) He further discussed the valveless venous passage of mercury into the pituitary and other areas of the brain from the nasal passages in his book Silver Mercury Fillings: A Hazard to the Human Brain. (76) Störtebecker confirmed his theory of the nasal pathway through conducting experiments with dogs. (77) The dogs were sacrificed soon after inhaling low levels of mercury vapor. The graph demonstrates the ability of the brain to selectively accumulate mercury. Those areas closer to the nasal passages had considerably more mercury than the areas farthest away.
Posterior Brain 50.
Frontal Brain 300.
Olfactory Lobe 550.
Nasal Mucosa 1550.
In an earlier experiment, Dr. Alfred Stock had studied the transport of mercury to the brain via the nasal mucosa by applying a mercury-containing ointment to the nasal mucous membrane during the final hours of a terminal cancer patient's life. Postmortem examination for mercury content revealed a considerable accumulation in that short time in both the pituitary and frontal brain.
Medulla Oblongata 300.
Olfactory Bulb 575.
Dr. Stock concluded that the high concentration of mercury in the pituitary was best explained by the assumption that it was transported there from the olfactory bulbs, since they too contained a larger quantity of mercury. (78) (While such types of experiments may be criticized by today's standards, they were considered the norm at that time. Still, the information they provided was virtually ignored for 50 years until a young Swedish scientist, Magnus Nylander, D.D.S., devised a way to study dentists.)
Our present level of exposure to mercury is associated with many health problems, most notably birth defects and neurological disorders. (79,80,81,82,83) A 1987 study by Sikorski identified a significant positive correlation between mercury levels in the hair of occupationally exposed women and the occurrence of reproductive failures and menstrual cycle disorders. (84) Recently reported in the literature is the case of a young dentist, professionally exposed to mercury for 35 weeks during her pregnancy, who delivered a severely brain-damaged infant. (85) Could this tragic outcome possibly have been prevented if dentists were more aware of the hazards of mercury poisoning in their practices?
The authors of the textbook Occupational Hazards in the Health Professions cautioned against comprehensive amalgam work during pregnancy. (86) Koos and Lango stated as early as 1970 that their research indicated that fertile women should be exposed to no more than 10 Hg µg/m3, and pregnant women should be exposed to no mercury at all. (87)
In this modern day when most offices have several mechanical mixers, exposure seems to be increasing nevertheless. Some authors have felt that the type of amalgam capsule is of critical importance. (88) Precapsulated mixes appeared to reduce exposure if handled properly. (90) Other investigators have found no correlation between the care with which mercury is handled and exposure levels.
It is likely that the use of this material makes exposure inevitable. (91) Furthermore, at present no known procedure will permit this material to be implanted in the mouth and still keep the patient's breath within the EPA standards for the air.
Clearly, women in dentistry are at the greatest risk from exposure to this toxic substance. One assistant's death has been reported. (92) The United States Environmental Protection Agency states that Women chronically exposed to mercury vapor experience increased frequency of menstrual disturbances and spontaneous abortions; also a high mortality rate was observed among infants born to women who displayed symptoms of mercury poisoning. (93) It would be interesting, then, to examine the literature for evidence that dentists and dental personnel are absorbing higher than normal amounts of mercury.
Dental Personnel Health Risks.
The kidney filters the blood, and as a result chronic exposure to chemicals might eventually induce kidney damage. A 1988 study by Verschoor, et al. evaluated the kidney function of 68 dentists (63 men, 5 women) and 64 female assistants who were apparently healthy, not pregnant, and taking no drugs. They compared the results of their kidney function analysis to 250 workers known to be exposed through the workplace to lead, cadmium, or chromium. Their conclusion was that Dentists and dental assistants appear to have a higher potential risk of kidney function disturbances than the workers in these industries. Although this study did not present evidence for changes of renal function parameters in dental practice in relation to Hg-urine levels below 20 µg/l, it certainly suggests that dental practice may carry a risk of renal dysfunction. There is a need to assess the renal hazard of the potential nephrotoxic chemicals used in dental practice. (94)
Kuntz followed 57 prenatal patients with no known exposure to mercury for changes in whole blood from initial prenatal examination to delivery and postpartum hospitalization. The mothers' whole blood total mercury increased during pregnancy from .79 ppb at initial examination to 1.16 ppb at delivery. This represents a 46% increase during pregnancy. Mercury has previously been recognized for its particular ease of crossing the placental membrane. The umbilical cord blood was also sampled at birth and found to have even higher levels of mercury at
1.5 ppb. (95)
After careful analysis of the data, Kuntz concluded: Previous stillbirths, as well as history of birth defects, exhibited significant positive correlation with background mercury levels. He further stated that patients with large numbers of dental fillings exhibited a tendency to higher maternal blood levels, which agrees with both Ott and Abraham. (96) A valid criticism of the study is that the levels of mercury found were too close to the controls to conclude without further study that a definite correlation with stillbirths has in fact been proven to exist.
Do Women Exposed to Mercury Vapor Have a Higher Incidence of Menstrual Disturbances?
Mikhailova, et al. found that 26.8% of women working in a mercury polluted atmosphere suffered from menstrual disturbances. Marinova, et al. found that 29% had hypomenorrhoea. (97) The controls found only 0.3% with the same condition. Hypomenorrhea occurred in 15.3% of the exposed group and only 0.6% of the nonexposed group. This could mean that more than 44% of female dental personnel working under these conditions will suffer from reproductive disorders due to mercury in the dental office. This hypothesis is corroborated by two other studies of women occupationally exposed to mercury which found that 36% to 45% will develop these types of disorders within 6 months of employment, a proportion that increases to 67% within 3 years of employment(98,99).
The most common symptoms were dysmenorrhea (painful menstruation), hypomenorrhoea, anovulation (infertility >40%), and hypomenorrhea. These symptoms are known to increase in populations additionally exposed to lead. (100) The relationship between spontaneous abortion, stillborn infants, and mercury has also been confirmed. (101)
Problems that may develop in the foetus from maternal exposure are not always evident at birth. Such delayed problems include diminished learning capacity, muscle spasms, and altered electroencephalograms. Exposure continues to increase if the infant is nursed, since mercury concentrates 8 fold in breast milk. (102,103)
Proper Handling of Amalgam.
The ADA and others have repeatedly pointed out that dentists are exposed to large amounts of mercury both in school during their training and in their profession through the use of this restorative material. In addition, mixed dental amalgam has been ruled a hazardous substance by the U.S. EPA. Specific instructions in the disposal and handling of dental amalgam have been given. (104,105)
1) A no-touch technique of handling amalgam should be used. Direct contact or handling of mercury, amalgam, or other mercury-containing materials should be avoided.
2) All amalgam scraps should be salvaged and stored in a tightly closed container. They should be covered with a sulfide solution such as X-ray fixer solution.
3) Skin exposed to mercury should be washed thoroughly.
4) Precapsulated alloy should be used, and used capsules resealed.
5) Water and high-volume evacuation should always be used, both when removing old fillings and when finishing new restorations. Evacuation systems should be passed through filters, strainers, or traps, and not exhausted into the office or directly into the sewer.
6) A face mask should be used to avoid breathing amalgam dust.
7) The dental office should be monitored for mercury vapor once a year or more often if contamination is suspected.
8) Periodic urinalysis of all dental personnel should be conducted.
Many skeptics maintain that if mercury were as dangerous a poison as numerous medical, environmental, occupational, health, and safety agencies have concluded, then there should be overt symptoms of mercury poisoning in the dental profession. Although that is not a very scientifically valid approach, it appears to be a reasonable hypothesis. The next area we will examine, then, will be additional evidence of mercury poisoning and related injuries in the dental profession.
Some authorities believe that mercury/silver fillings are not a problem except for the rare individual who is hypersensitive to mercury. (107) There is no scientific evidence to support this contention. However, assuming that it were true for the general public, it would also be true for dental personnel.
A hypersensitive response is an abnormal immune reaction to an allergen. Mercury is an allergen. Numerous health problems have been related to allergic reactions to mercury. Idiosyncratic responses to metallic mercury have been documented since the last century. In 1943 Bass submitted a case report of urticaria response in a child after receiving dental amalgam fillings. (108) Also documented in the scientific literature are chronic atrophic dermatitis ,(109) contact dermatitis, (110,111,112,113) eczematous dermatitis ,(114) multiple polyposis (115) generalized allergic reactions 116,117,118,119) oral lichens planus (62% of those with lichens planus tested allergic) (120,121,122,123) chronic oral ulcerations ,(124) and burning mouth .(125)
Two studies have examined the risk of hypersensitivity to inorganic mercury in dental personnel. The first tests were by White and Brandt, who patch tested dental students with mercuric chloride and silver amalgam to determine their hypersensitivity.(126) As you can see by the table, freshmen tested lower than seniors in mercury hypersensitivity. The study concluded that exposure during training in dental school could lead to increased hypersensitivity response in students.
First Year Student 2%.
Second Year Student 4%.
Third Year Student 11%.
FourthYear Student 10%.
A more recent study by Miller, et al. found an increase in hypersensitivity corresponding not with years in school, but rather with increasing number and age of the subjects' amalgam restorations. (127) Overall, they found an even greater percentage of the 171 dental student participants who tested allergic/hypersensitive to mercury.
Miller's study considered freshmen dental students to be representative of the general public. He found that 31.4% of freshmen tested positive to mercuric chloride.
Djerassi also tested for allergy and found that of those with amalgams, 16.1% tested allergic, whereas none of the 60 control subjects without amalgams tested allergic. (128)
Neuman, a dental professor and spokesperson for the ADA, contended at the California Dental Association meeting in 1987 that the positive patch test is actually a chemical burn and is not related to mercury hypersensitivity. (129) The protocol of this and other studies has precluded that possibility. The negative controls for both the Miller study and the Djerassi study found that 0% of those who had no fillings tested positive for hypersensitivity. (As an interesting side note, in California it is against the law for tattoo artists to use red dye in their designs, because it contains mercury. There are reported cases of the development of hypersensitivity to dental fillings after placement of a red tattoo. )(130)
Miller concluded that hypersensitivity is apparently related to subjects' number of amalgam fillings and the length of time they have been in place, rather than to the number of years spent in the dental profession. The risk of developing an abnormal response increases with both time worn and number of fillings. Contact dermatitis has indeed forced a number of dentists out of practice, since they could no longer wear gloves or handle amalgam. It is considered an occupational hazard, with approximately 11% of all dentists displaying an allergic hypersensitivity reaction to gloves. (131)
In a study of 298 dentists, Shapiro measured their mercury levels by X-ray fluorescence. Of those dentists with greater than 20 µg Hg/liter tissue levels, 30% had polyneuropathies, while those dentists with no detectable mercury levels had no polyneuropathies. Shapiro concluded that these findings suggest that the use of mercury as a restorative material is a health risk for dentists. (132)
Dr. Magnus Nylander devised a series of experiments utilizing neutron activation analysis (NAA) to study the mercury content of brain tissues of amalgam bearers, non-amalgam bearers, and dentists. NAA is the most accurate method currently known to science to evaluate trace minerals. What he found in the cases of 7 dentists and 1 dental nurse was that all had a surprisingly high pituitary mercury content, totally out of proportion to the content found in other parts of the brain. Values ranged from 135 to 4,000 nanograms Hg per gram tissue. (133,134) He also found in a related study of dentists and dental assistants in Sweden that they have twice the incidence of brain tumors as nondental personnel. (135)
Pituitary Occipital Ratio
1) Dentist 4,040 300 14:1
2) Dentist 3,650 84 43:1
3) Dentist 2,700 16 69:1
4) Dentist 350 40 9:1
5) Dentist 350 5 70:1
6) Dentist 350 17 18:1
7) Dentist 135 19 7:1
8) Assistant 1300 18 72:1
Amalgam bearers 7-77 3-23 Cases 9-23
Mean 28 11 2.5:1
24) 10 6 2:1
25) 5 6 1:1
The evidence is clear that we are exposing ourselves and our patients to a known toxic material through the use of mercury in dentistry. One of the principal reasons this has happened is the strong advocacy position of the American Dental Association in support of the use of this material.
Author Dr. David Kennedy
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