Drug – bio-affecting and body treating compositions – Identification or warning feature – Taste or smell or chemical irritation to the eye – nose – or...
Patent
1988-09-14
1989-08-22
Rose, Shep K.
Drug, bio-affecting and body treating compositions
Identification or warning feature
Taste or smell or chemical irritation to the eye, nose, or...
484 49, A61K 716
Patent
active
048594539
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a composition for preventing mercury present in amalgam fillings from passing into and poisoning the body.
Modern dental amalgam comprises an alloy of silver, tin and copper, possibly with additions of zinc, indium and/or palladium. This alloy is mixed with mercury (between 40 to 54% by weight Hg). The resultant pliable compound is then packed into dental cavities from which defective matter has been removed. The amalgam is allowed to harden over a period of from eight to twenty four hours, and when hard provides a mechanically strong filling.
It is well known that mercury is a toxic substance. The maximum permitted mercury content of air is 0.05 mg/m.sup.3. Liquid mercury has a low vapour pressure and air which has a temperature of 20.degree. C. is not saturated until levels in excess of 10 mg/m.sup.3 are reached. The poison is readily absorbed by the body, via the skin, the digestive organs and the lungs. About 76% of the mercury inhaled will remain in the lungs for approximately two whole days. Mercury from the oral cavity passes readily through the cells and into the blood. Mercury also dissolves readily in the lipoids (steroles, phosphatides, cerebrosides and coratenoids). The lipoids often form surface layers in the cells and are significant to the ability of the cells to take up dissolved substances. Because of its high solubility in the lipoids, mercury will dispense readily to the brain, liver and kidneys with a half-life of between 40 and 80 days.
Tests were carried out on several people with amalgam fillings, for the purpose of measuring the amount of mercury contained by the gases of expiration. The results obtained showed that the level of mercury present exceeded the permitted level in many of the cases investigated. It has also been observed that the level of mercury concentration increases in conjunction with brushing of the teeth and chewing chewing-gum. It was found that chewing gum gave rise to a 15% increase in the mercury content. The central nerve system is the organ which is most critical with regard to the toxic effects of inhaled mercury (WHO 1976). Although elementary mercury oxidizes quickly in the blood, some of the mercury present will pass through the blood-brain-barrier before oxidation is complete. The earliest symptom at chronic low-level exposure is physiological, such as loss of memory and mental disturbances, inability to concentrate, tiredness, depression and headaches. Higher exposures result in more serious injury. Researchers are not certain of the lowest concentration at which damage is liable to be caused. According to Professor Stock (1941) symptoms of mercury poisoning are observable at levels of 10-20 ng Hg/l, while other researchers report that no symptoms could be observed at levels up to 50 ng/l. (Bull. Environ. Contam. Toxical. 1985:34,459-468)
These problems have been, and still are, the subject of lively debate. Various theories have been put forward, of which some maintain that mercury which derives from amalgam deposits is innocuous, while others maintain that there is no doubt that such deposits are the cause of many of the dental problems which have become so common today and which are often mentioned in conjunction with oral galvanism.
Four Swedish researchers, who are also dentists, have reached the conclusion that amalgam causes mercury poisoning. In one case in Ostergotland, Sweden, one woman had her fillings replaced when it was established that the fillings had caused mercury poisoning. The symptoms in this case were giddiness, sore throat and cardiac problems. Another researcher in Linkoping, Sweden has studied amalgam fillings in an electron microscope, and has found that amalgam fillings are not as stable as earlier believed. Mercury was found to leak constantly from the fillings examined. Droplets of mercury migrate to newly ground surfaces. After twenty four hours these droplets amalgamate to form small pools. Mercury is also released from amalgam fillings by corrosion and diffusion, although the researchers
REFERENCES:
patent: 4057649 (1977-11-01), Bensalem
patent: 4385892 (1983-05-01), Sato et al.
Andheden Sigvard
Muller Arthur
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