Assessing the Environmental and Health Adverse Effects of Mercury Released From Dental Amalgam: A Literature Review

Abstract

This paper reviews the most available data on the possible adverse effects of mercury released from amalgam that comprises 50% pure mercury, 35% silver, 12-13 % tin, 2% copper, and up to 1% zinc, indium, platinum, and palladium. Despite the possible health risks of mercury from amalgam on the nervous, respiratory, renal, and endocrine systems, it is used in some countries; however, Sweden, Denmark, Canada, the United States, and Japan have long banned the use of amalgam. Amalgam restorations are one of the main mercury-releasing sources (1800-2700 tons per year) of contamination. During chewing, grinding, brushing of teeth, breaking down of amalgam, and as the temperature of the oral environment increases, mercury vapor will be released. The mercury vapor enters the atmosphere, wastewater in dental offices, all systemic organs, especially the lower respiratory tract and can affect the renal-urinary system or enters breast milk, fetus, and finally, transmits to infants. The mercury level released from amalgam in blood, urine, hair, and nail of large populations of dentists, dental assistants, and pregnant women is higher than the safe levels. The main neurological and psychological effects of mercury vapor are sleep disorders, amnesia, mental disorders, hair loss, memory disturbances, multiple sclerosis, Parkinson’s disease, kidney diseases, gene toxicity, Alzheimer’s disease, Autism, skin allergies, cancer, infertility, low birth weight, and heart diseases. In order to avoid further amalgam risks to the dentists, dental assistants, pregnant women, and wildlife ecosystem, it is suggested to replace the dental amalgam with composite resins.