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Strive-The Student View Mercury Removal Prior to Cremation: A Collaboration of Dentistry and Mortuary Science to Prevent Environmental Contamination By Paige Christiansen RDH, BS, RF, and Mickensi Larson RDH, BS, RF
Mercury contamination occurs in the environment through a process called bioaccumulation (Figure 1).[1,2] Heating processes used in power plants, industrial manufacturers, crematoriums and natural sources like volcanoes vaporize mercury particles and are released into the atmosphere in its elemental molecular form, Hg. Returning to the earth in the form of rain or snow, these molecules are consumed by microorganisms in the soil which convert the particles into methylmercury, CH3Hg+. Methyl molecular groups, attached to the elemental molecule, are what make this composition a deadly neurotoxin to humans and wildlife from its ability to cross the blood-brain barrier.[1] The amount of methylmercury increases exponentially as microorganisms are consumed by larger microorganisms, which are then eaten by successively larger organisms, fish and animals. By the time methylmercury bioaccumulates up the food chain in large fish such as tuna, the presence of methylmercury could pose a serious threat to both animal and human health.[1] By 2025, it is estimated that 57 percent of people who die in the United States will be cremated, a substantial increase from 20 years ago.[5] Cremation is utilized as a form of final disposition for several reasons. It is less costly than traditional burial, society has an increased awareness of environmental considerations, and ties to family traditions are becoming less evident. Religious views of traditional burial have also changed, making cremations an acceptable form of final disposition. With the growing elderly population and better oral health measures, many people die with heavily restored mouths. Forty years ago, about 75 percent of those over the age of 75 were edentulous. Today, that statistic has reversed with 75 percent of those having some form of dentition at the time of death.[6] Amalgam is one of the most common dental materials used in this aging generation. The mouth of an elderly person has an average of 8.6 amalgam restorations. Mercury makes up nearly 50 percent of an amalgam restoration; therefore, each cremation emits approximately 3.2 grams of mercury.[5] Since cremation was not commonly practiced in the past, the effects of resulting vaporized mercury had not been closely examined. Today, crematoriums stand as the third largest source of mercury emissions, behind steel and cement manufacturing.[1] For the mortuary science and dental communities, many issues of concern arise. How will the amalgam fillings and core build-ups be identified in the mouth? Some education is needed to identify amalgam on a radiograph, and it is nearly impossible to determine build-up material underneath crowns without recorded documentation or removing the crown to visually confirm its existence. How will the teeth be removed? The process of amalgam removal would need to be determined. Local anesthetic would not be necessary, nor would the concern for tissue healing. Mechanical removal and de-crowning have both been suggested methods. Who should be responsible for the removal of teeth? Dentists, dental hygienists, morticians, funeral directors or crematorium employees are potential candidates for this new responsibility. With potential changes in crematorium regulations, these unanswered questions could present an opportunity for collaboration among the dental, dental hygiene and mortuary science professions. Those most concerned with this issue are exploring ways to regulate crematoriums so that future contamination can be reduced or eliminated. Recommendations have been brought to government officials all over the United States. Minnesota presented a bill in the 2007-2008 legislative session requiring the removal of amalgam restorations prior to the cremation process. While this legislation did not pass, bill writers continue to work on a proposal that would be adequate as law.[7] In Colorado, the Department of Public Health and Environment has launched the Mercury-Free Colorado Campaign, which, in part, focuses on efforts to remove mercury before the cremation process.[8] There are also several other states whose community members and political leaders have begun to address the issue of mercury contamination. What can we, as a dental community, do about this? As state legislators across the country attempt to answer these questions, they will have to consider the need for environmental health without compromising the ethical treatment of human remains. It will be important for the dental hygienist to be aware of the latest regulations in order to answer patient questions and educate the public about the relationship between amalgam in the mouth and mercury in the environment.
References
Paige Christiansen and Mickensi Larson presented “Mercury Removal Prior to Cremation” at the Center for Lifelong Learning at ADHA Annual Session in Washington, D.C. in June 2009. They graduated with Bachelor of Science degrees from the University of Minnesota in August 2009. They now work as dental hygienists in east-central Minnesota. The faculty mentors for this edition of Strive were Kimberly S. Johnson, RDH, BS, and Sandra Myers, DMD.
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Amalgam is American Dental Association (ADA) and Food and Drug Administration (FDA) approved for its long-lasting and effective restorative properties. The ADA recently stated, “Dental amalgam has been studied and reviewed extensively, and has established a record of safety and effectiveness.” Today, amalgam waste is appropriately handled according to regulations to prevent any excess amalgam from entering the environment through waste water. Amalgam is considered safe to be used in the mouth because the oral cavity does not come in contact with temperatures high enough for the mercury to vaporize.[3,4]
