Mercury

“The rate of mercury vapor emission from setting dental amalgam was measured by use of an ultraviolet light absorption technique under non-diffusion controlled conditions.”

“Twelve hundred subjects in North America were patch tested identically with 16 allergens. Thirteen dermatologists representing ten separate centers participated in this epidemiologic study. The most common sensitizers observed include nickel sulfate, potassium dichromate (VI), thimerosal (Merthiolate), p-phenylenediamine, ethylenediamine, neomycin sulfate, and turpentine oil. Results of this North American study are compared to those published by the International Contact Dermatitis Research Group. The data permits a more rational selection of antigens for efficient patch testing in North America. A new list of 19 screening allergens recommended by the North American Contact Dermatitis Group has been published.”

“Experimentation on the effect of restorative materials on the gingiva has been conducted on animals. This study was conducted on young human beings.”

“The work environment and procedures of twenty-three dentists and their assistants were surveyed for the existence of potential health hazards which could be associated with the preparation of mercury amalgam fillings. Data were collected on the work environment, ventilation, individual procedures, and hazard awareness related to the removal of old amalgam fillings as well as the preparation of new fillings. The results indicated that the greatest potential hazard may result from contamination of hands after working with mercury metal or fresh amalgam. Respirable dust, in terms of total concentration and mercury content, was also significant. This study also demonstrated the almost complete unawareness of most dental assistants and of many dentists that mercury could be hazardous; consequently, precautionary measures were almost nonexistent. A list of recommended precautionary measures is presented.”

“The case histories of four children and two adults who were accidentally given toxic amounts of Merthiolate are recorded. The possible modes of action of Merthiolate in causing symptoms are discussed. Five out of the six patients died, and necropsy showed extensive renal tubular necrosis in each case, and in two, evidence of diffuse intravascular coagulation.”

“The review evaluates the exposure of the patient to mercury and the long-term exposure of dental personnel, makes suggestions for minimizing any possible mercury hazards to the patient and dental personnel, and restates methods of disposing of mercury residue and waste amalgam to avoid any possible contamination of the environment through dental procedures. This review does not indicate any significant hazard to the patient. There is no contamination of the environment if proper office procedures are followed and if scrap amalgam is collected and salvaged.  Further, the review concludes that proper mercury hygiene minimizes any possible danger to dental personnel.”

“It must be stressed that ventilation of dental surgeries is all important as evidenced by the trials with the mercury vapour meter. Where there is a free current of air the level of concentration of mercury is not particularly high even when spilled mercury is found. When the surgery is enclosed, the level of mercury may be increased and become a hazard to health.”

“It has been demonstrated repeatedly that the effect on living cells of organic mercury compounds can be neutralized to a certain degree by the amino acid cysteine.”

Mercury, an essential element of dental amalgams, is not a stable material but one that vaporizes at ordinary temperatures. By use of a simple technique, printings were obtained from mercury amalgam specimens but were not obtainable from alloy-zinc control specimens. Unburnished and unpolished specimens yielded more intense printings than burnished and polished specimens.

“Decontamination of offices is difficult but essential. Mercury vapor suppressants should be used routinely by all dentists. Cleaning equipment should be confined to the dental office and should be replaced often. Air conditioner filters should be replaced often. Observation of spillage and contaminated cleaning equipment is a sign of significant exposure. Remedial action should be taken to reduce exposure. Medical assistance, including urinalysis for mercury, should be obtained.”