The future of amalgam in dentistry : Mercury toxicity

Few decades after its development in France in the 1800s, the controversy regarding the safety of dental amalgam instigated because mercury is the key element in dental amalgam. Considering the toxic effects of mercury to the human health as well as to the environment, its use as a dental restorative material has declined over years.

 Mercury toxicity is a concern in dentistry because mercury and its chemical compounds are toxic to the kidneys and the central nervous system. The most significant danger is from mercury vapor.
Mercury has a high vapor pressure and
evaporates at room temperature. The lungs absorb most of the mercury vapor in air when inhaled. This poses health risks to the dentists during the procedure if adequate precautions are not taken.

Global concerns and activities:
The mercury toxicity issue flared up  worldwide with the discovery of Minamata Disease in 1956 in Japan and  the role of Methylmercury found in the Industrial wastewater in causing the disease. Minamata Disease is a neurological syndrome caused by severe mercurypoisoning. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, loss of peripheral vision, and damage to hearing and speech. In extreme cases, insanity, paralysis, coma, and death follow within weeks of the onset of symptoms. A congenital form of the disease can also affect fetuses in the womb.  

Shinobu Sakamoto, a sufferer of fetal Minamata disease, speaks at a news conference ahead of the U.N. Conference of Plenipotentiaries on the Minamata Convention on Mercury on October 8, 2013 in Kumamoto, Japan. The 57-year-old developed congenital Minamata disease when she was in her mother's womb. Source:
 More dangerous effects are seen on ecology than on human health. The proper disposal of mercury has always been problematic. Norway has become the first nation to legislate a sweeping ban on the use of amalgam fillings in dental work. Previous laws forbid the use of mercury-containing fillings in more vulnerable segments of the population, such as pregnant women and children, but the new law is the first to forbid the use of the toxic metal without exemption. Tonnes of mercury fillings were being carried in the oral cavity in Sweden alone prior to its ban in effect from April 1st, 2008, and hundreds of kilos of mercury was released into atmosphere and water sources. Now, more nations are contemplating about banning mercury totally because it’s not rational to continue its use when other safer alternatives are available.

 IPEN is an organisation that has been actively involved in discouraging the use of any materials toxic to human health and environment. It has started a project, International Mercury Treaty Enabling Activities Program(IMEAP)  to reduce mercury pollution. Apart from mercury, it has campaigned against the use of toxic chemicals like DDTs, endosulfans, PCBs , lead, etc.

 On 10th October 2013, the Minamata Convention on Mercury at Kumamoto, Japan was organised where 128 countries including Nepal signed  an international treaty designed to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds.

 In the context of Nepal:
A two days national conference on Mercury Free Dentistry from May 26 to 27, 2014 has been organized by Center for Public Health and Environmental Development (CEPHED), jointly with Nepal Dental Association (NDA) in close coordination with the Oral Health Focal Point, Management Division, Department of Health Services, Ministry of Health and Population, Government of Nepal and supported by World Alliance for Mercury Free Dentistry (WAMFD), Asian Center for Environmental Health and UNDP GEF SGP.

Recommendations of National Conference on Mercury Free Dentistry
  • Comprehensive regulatory frameworks (Acts and Regulation) to promote mercury free health care services and mercury free dentistry in Nepal  by 2015/2016
  • General Practitioners and Professionals Associations have plan to phase down the use of mercury amalgam in children and pregnant women by 2017 and phase down the use of mercury amalgam from dentistry sector by 2018.
  • Representative of Academic University and Institutions have agreed to recommend and support for the revision of dental curriculum by 2019.
  • Issues of awareness raising, capacity building, and development of waste management facilities and encourage of insurance policy and tax exemption for mercury free alternatives.
  • Ratification of the Minamata Convention on Mercury as soon as possible.
Looking into all these recent advances, it can be assumed that Dental amalgam/ Mercury in dentistry will become a history within next decade.

By: Raman Dhungel

2. Clinical Aspects of Dental Materials 4th Edition, 2013
3. Applied Dental materials , 9th Edition