Nexus - 0208 - New Times Magazine-pages

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the Western World. No comparative studies of intelli- gence before and after the epidemics are possible, but the widespread exposure can be amply documented. The advent of the germ theory in the mid 19th century prompted the myth that mercury acted as a tonic that restored the body to its normal vigour and poisoned the germ directly. Notwithstanding the cumulating evidence in the late 1800s of the toxicity of mercury compounds, the use of mercurials as a treatment for syphilis contin- ued to be justified by the medical profession. In 1920, John H. Stokes, Chief of Dermatology and Syphilology at the Mayo Clinic in Rochester, Minnesota contended:- No matter in what form it is used, the action of mercury on syphilis is one of the marvels of medicine The use of mercurials as a treatment for syphilis did not cease until the discovery of penicillin, which cures the disease in the early stages. Today, the only medical treatment which persists in using mercury is the practice of mercury amalgam filling of teeth cavities. tested as less expensive alternatives to gold for filling teeth cav- ities. One alloy called “fusible metal" consisted of bismuth, lead, tin and mercury, and melted just under the boiling point of water. The melted mixture was poured into the patient's tooth cavi- ty. Later, an alloy melting at 60°C was used. Small pieces of the metal were placed on the tooth and touched with a hot instrument to cause it to melt and flow into the cavity. Burns to the mouth and face were direct hazards of these early mercury alloy treatments. However, a French dentist M. Taveau, in 1826 used powder filed from silver coins and mixed with mercury to form a soft putty which later hardened. This putty could be placed in the teeth cold and easily shaped. Initial problems involved the swelling of the fillings but better alloy mixtures and techniques were soon devel- oped. When the technique was brought the United States in the 1830s it touched off a controversy which has since been called the "The Great Amalgam War" between dentists preferring the new amalgam treatment and dentists advocating the gold only. The lat- ter group vigorously attempted to discredit mercury amalgams by contending: that the poisonous element could endanger the patients health’ Subsequently, the newly formed American Society of Dental Surgeons requested members to sign a pledge refusing to use amal- gams.* It was not until 1895 that the question of amalgam compo- sition was settled by Dr. G.V. Black of Northwestern University, who after years of research demonstrated the proper quantities of mercury in amalgam to make an effective restorative material.’ The use of mercury amalgams was not further questioned until 1926 when Professor Alfred Stock at the Kaiser-Wilhelm Institute of Chemistry found evidence indicating that mercury could be absorbed from dental amalgams and that this had led to serious health problems. He concluded his findings with the remarks: Dentistry should completely avoid the use of amalgam for fillings or at least not use it whenever this is possible. There is no doubt that many symptoms: tiredness, depres- |: the early part of the 19th century a number of alloys had been JUNE-JULY 1992 sion, irritability, vertigo, weak memory, mouth inflamma- tions, diarrhoea, loss of appetite and chronic catarths often are caused by mercury which the body is exposed to from amalgam fillings, in small amounts, but continuously. Doctors should give this fact their serious consideration.. It will then likely be found that the thoughtless introduction of amalgam as a filling material for teeth was a severe sin against humanity? Professor Stock is reported to, some years later, have repudiated his earlier claims’, however this repudiation is disputed and may have actually been a translation error.® The reassurances of the inertness and safety of dental amalgams . continued to prevail unti) the late 1970s when H.A. Huggins, in the light of the new public awareness of the extreme toxicity of mer- cury compounds brought to public attention as a result of several man made environmental mercury disasters once again pointed to the possible toxic contribution from dental fillings.” nous for two millennia, the lack of appreciation of the nature of mercury toxicity, whereby exposure to extremely small amounts of mercury over long periods of time is not only very harmful but accumulates during this exposure in the brain and other tissues, led to a carelessness in industrial practices which has resulted in untold human suffering and tragedy. Exposure of workers to mercury nitrate which figured in the car- rotting process of fur felt was commonplace, as were the toxic side- effects upon those who were exposed. The phrase ‘Danbury Shakes' is still used in some parts of the USA, and derived from the civil war production of soldiers’ hats in Danbury, Connecticut. The phrase was intended to caricature the condition of muscle tremor and spasm caused by neurologic damage which accompanied the madness associated with industrial mercury exposure. The charac- ter of the Hatter in Lewis Carroll's Alice's Adventures in Wonderland was of course intended to reflect the severe mental disturbances manifest by people working in the fur felt hat indus- A Ithough mercury compounds had been known to be poiso- try. Despite these obvious warning signs of last century, the imple- mentation of the 20th century industrial chemical technology has meant a steadily increasing contribution of man made mercury compounds to the environment. Mercury based chemicals have been used as fungicides to treat grains, as pesticides for vegetables particularly potatoes, as mildew inhibitors in household water based latex paints, as a wood preservative, as an anti-sliming agent in wood pulp processing, as a catalyst in the production of a num- ber of plastics including PVC and in the production of major chem- icals such as chlorine and caustic soda.” Elemental mercury is used in a number of types of lighting tubes including fluorescent lights and neon lights, electrical switches and numerous laboratory and medical equipment from thermometers to sphygmomanometers. Thus mercury enters the environment when old light fittings are discarded, certain laboratory apparatus is bro- ken and mercury spilled. Mercury enters our homes and work- places from painted material. Indoor latex paint may contain up to NEXUS °17 MERCURY AND DENTAL AMALGAM MERCURY IN THE ENVIRONMENT - WARNING SIGNS