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The dental amalgam controversy is a debate over the use of Amalgam s containing Mercury as a Dental Filling . A minority of Dentist s have always been opposed to the use of amalgam in dental fillings, since they first came into use over 150 years ago. The essence of the controversy is that it is intrinsically difficult to scientifically demonstrate either conclusive Safety or conclusive Harm without very large-scale long-term Epidemiological studies of the type that have not so far been performed, and might in any case be impossible due to ethical considerations. BACKGROUND See Also: Dental amalgam Dental amalgam is a mixture, WHO - Mercury in Health Care :Amalgam is a mixture of mercury and a metal alloy page 1 item # 2, third paragraph. rather than a true Alloy , of Mercury along with other metals like Silver , Tin , Copper , and Zinc .1 Cadmium , Indium , Palladium and Lead were historically found in some amalgam products.2345 Amalgams have been used in Dentistry for over 150 years because they are malleable, durable, and more affordable than Gold or composites. While it is accepted that amalgam fillings release mercury,67 it is generally argued that the amount of mercury released by amalgam fillings is negligible, thus there is no significant danger from mercury leaking from fillings into the body.http://www.ada.org/prof/resources/positions/statements/amalgam.asp Opponents of amalgam argue that long-term exposure to the low levels of mercury vapor causes Neurodegenerative Disease s, Birth Defect s, and Mental Disorder s. Experts acknowledge the risks of exposure to mercury in any form, while noting that effects of exposure to dental amalgam are not evident at the population level despite its past ubiquity. Better dental health overall coupled with increased demand for more modern alternatives such as resin composite fillings (which match the tooth color), as well as public concern about the mercury content of dental amalgam, have resulted in a steady decline in dental amalgam use, so the issue may eventually become moot.8 HISTORY AND OVERVIEW See Also: Dental fillings Minority dissent over amalgam has been a stable feature of informed debate among dentists almost since its invention. In 1840, the in patients and dentists (at the time, dentists made amalgam by mixing liquid mercury and the other components of amalgam themselves in their office, a practice which continued until pre-filled amalgam capsules became generally available in the 1960s).http://www.fauchard.org/publications/history/Journal_00_48_2p75.htm During the next decade some members of the society were suspended for the use of amalgam. Because of its stance against dental amalgam, membership in the American Society of Dental Surgeons declined, and due to the loss of members, the organization disbanded in 1856. Solyman Brown, a Giant of Dentistry and its Poet Laureate - ''"... the dispute over the propriety of the use of amalgam in practice -- termed the "Amalgam War" -- led to the demise of the organization a few years later. "'' In 1859, the American Dental Association (ADA) was founded by twenty-six delegates representing various dental societies in the United States at a meeting in Niagara Falls, New York. The ADA did not forbid use of amalgams. The ADA position on the safety of amalgam has remained consistent since its foundation. As of 2006, ADA has over 152,000 members and is the largest and longest-standing professional association of dentists in the world. Amalgam formulations and properties were gradually improved, notably by Dr. G.V. Black in 1895. Despite these changes, debate over the use of amalgams persisted in the dental profession. The ADA maintained until 1984 that mercury was bound in amalgam and did not release mercury vapor. In the 1970s studies demonstrated that a small amount of mercury vapor was constantly being released from amalgam, corroborating the first such study published in 1882 in the Ohio State Journal of Dental Science by Dr. Eugene S. Talbot.http://art-bin.com/art/otalbot1882.html The majority of dentists maintain that dental amalgams are not only safe for use but desirable, since they are cheap, easy to use, fairly durable and strong, can be quickly inserted into the oral cavity and that any release of mercury vapor is negligible. Opponents, however, argue that repetitive exposure to a very small amount of mercury can be cumulative, so amalgams can cause health problems. Those in favor of Amalgam fillings (the majority view in the USA and elsewhere) indicate that significant measurable adverse health effects from them have not been proven conclusively. Those against Amalgam fillings (the minority view in the USA ) indicate that their Safety has not been proven conclusively. Because both of these statements are objectively true, the Controversy continues without resolution to date. REGULATION AND GOVERNMENTAL INVOLVEMENT Some legislators have introduced Legislation to prohibit or restrict use of amalgam fillings. In 2001 in a lawsuit involving California Proposition 65 and amalgams, a California Superior Court judge ruled that all dental offices with more than nine employees must provide notices on the contents of dental fillings. The mandated notice reads: Notice to Patients, Proposition 65: Warning on dental amalgams, used in many dental fillings, causes exposure to mercury, a chemical known to the state of California to cause birth defects or other reproductive harm. Root canal treatments and restorations including fillings, crowns and bridges, use chemicals known to the state of California to cause cancer. The U.S. Food and Drug Administration has studied the situation and approved for use all dental restorative materials. Consult your dentist to determine which materials are appropriate for your treatment. Some countries, such as and Germany , have some restrictions on dental amalgam, such as permitting its use for the general population, but not for children, pregnant women, people with kidney problems, when in contact with other metals, such as braces, and in people with mercury sensitivity. In . In an interim period between July 1, 2002 and 2007, the bill would have required labeling of amalgam with a warning. The bill was referred to a subcommittee, which Tabled it. It has since been re-introduced as bill HR-4011 by congresswoman Diane Watson,http://www.iaomt.org/documents/WATSON_021_XML1.pdf who issued a public statement after the September 2006 decision of the FDA Review panel on dental amalgam. FDA’s Ruling Signals Beginning of End of Mercury Fillings - Web site of Congresswoman Diane Watson - Press Release - accessed 11 October 2006 In most Europe an countries (for example, the United Kingdom , France , and Italy ) and the United States, amalgam use is unrestricted. In the United States, amalgams are classified as a "device," not a "substance," by the Food And Drug Administration (FDA). Under the U.S. Code of Federal Regulations, amalgams are a Prosthetic device: Amalgam Alloy, (a) Identification. An amalgam alloy is a device that consists of a metallic substance intended to be mixed with mercury to form filling material for treatment of dental caries. (b) Classification. Class II. As a result of this classification, amalgams have not been subject to official government testing in the United States such as is required for medicines. However, the FDA maintains a web page on the use of amalgam, last updated in December 2002, on which it states, "no valid scientific evidence has shown that amalgams cause harm to patients with dental restorations, except in the rare case of allergy."http://www.fda.gov/cdrh/consumer/amalgams.html As described above, this earlier conclusion by the FDA was called into question by a panel of scientists in September 2006, when a joint meeting of three FDA committees reviewed and discussed peer-reviewed scientific literature on dental amalgam devices.http://www.fda.gov/oc/advisory/accalendar/2006/cdrh12518dd09060706.html Prior to the joint meeting, some scientists and consumer advocates had raised questions about the fairness of this process, as planned by the FDA.http://www.toxicteeth.org/ADVISORY%20FOR%20HEALTH%20AND%20SCIENCE%20MEDIA.pdf Following the meeting of the joint committees on 6-7 September 2006, when the panel of outside advisers that the FDA had asked to assess the conclusions of its report on amalgam safety rejected the FDA report in a 13-7 vote, they stated the report's conclusions were ''"unreasonable"'', given the quantity and quality of information currently available. Panelists said remaining uncertainties about the risk of so-called silver fillings demanded further research, in particular, on the effects of mercury-laden fillings on children and the fetuses of pregnant women with fillings and the release of mercury vapor on insertion and removal of mercury fillings. Michael Aschner, a professor of pediatrics and pharmacology at Vanderbilt University and a panel consultant said "There are too many things we don't know, too many things that were excluded." ''FDA advisers: Safety of mercury fillings needs more study'' Retrieved 10 September,2006 ''Are mercury tooth fillings really safe?'' Retrieved 10 September, 2006 ''FDA Panel: Fillings May Not Be Safe'' Retrieved 12 September 2006 Shortly after the decision of the joint advisory panel, the president of the International Academy Of Oral Medicine And Toxicology (IAOMT) wrote to the FDA to ask for an expanded review of current science on dental mercury amalgams, a definitive date for such a hearing, and a format that will assure that the full breadth of health effects is assessed. [http://www.iaomt.org/documents/FDA.LTR%209-12-06%20RECONVENING%20PANEL%20-%20FINAL.pdf Request to reconvene joint meeting of the: ''Dental Products Panel & the Peripheral and Central Nervous System Drugs Advisory Committee''.] In a press release the ADA wrote that it " welcomes the call by a U.S. Food and Drug Administration (FDA) panel for additional review of scientific studies on the safety of dental amalgam fillings." and reiterated that "the overwhelming weight of scientific evidence supports the safety and efficacy of dental amalgam, and it should continue to be made available to dentists and their patients " and " dental amalgam contains elemental mercury combined with other metals such as silver, copper, tin and zinc to form a safe, stable alloy. " ADA Welcomes Additional Scientific Review of Dental Filling Safety POINTS OF CONTENTION Available alternatives One argument against the use of amalgams in dentistry is that a number of less controversial, safer alternatives exist, like composite resin (or "white") fillings that have been available since the 1980s. Other alternatives include gold, porcelain, and glass Ionomer s. Amalgams are stronger, more durable, and less expensive than most of the available alternatives, though some newer composite materials have demonstrated durability on par with amalgam. Most of these materials, except gold which has been used longer than amalgam, have not had as long a period of use and study as amalgam, and some of them are known to contain other potentially hazardous compounds. This is one reason why Biocompatibility testing is recommended for all dental materials as per ADA/ANSA or ISO standards, and can be performed by specialized laboratories.9 Some experts also caution against a too-sudden shift towards composite resin to allow time for dentists to acquire the skills needed to properly place resin fillings since ''" clinical studies on the longevity of amalgam and resin composite restorations placed by dental students and dentists who are experienced in both composite resin and amalgam placement show a comparable and acceptable annual failure rate for those restorations ".'' 10 Teaching of amalgam techniques to dental students is declining in some schools in favor of composite resin,11 and at least one school, University of Nijmegen in the Netherlands, had eliminated dental amalgam from the curriculum entirely as of 2001.12 Environmental impact Mercury is an environmental toxin and the World Health Organization , OSHA , and NIOSH have established specific occupational exposure limits. Amalgam removed from teeth is classified as toxic waste in various countries. Mercury from improperly disposed of amalgam may be released into sewage water. Crematoria are to establish recovery of mercury from flue gases as soon as reasonable since mercury from amalgam is released into air during cremation of cadavers with amalgam fillings. Environmental risks are mitigated provided that amalgams are disposed of properly. ISO has issued standards regarding the proper handling and disposal of amalgam waste, and legislation to enforce these standards is being adopted in some states.http://www.dec.state.ny.us/website/dshm/redrecy/mercfaq.htm General health effects Dental amalgams have been suspected by some medical practitioners, particularly of integrative or Alternative Medicine , of causing many physical and/or psychological problems. They reason that, since mercury is poisonous and Neurotoxic , amalgams known to release mercury into the mouth are indisputably a source of poison. These persons argue that amalgams can cause neurodegenerative diseases, Birth Defect s, and Mental Disorders . While it is proven that mercury exposure can cause health problems such as these, the potential Adverse Effects of amalgam itself on health has not yet been resolved. Two recently released comprehensive reviews of papers published in peer-reviewed journals arrived at opposite conclusions. One released in December 2004 in the US found little evidence to link mercury fillings to health problems13 ( Google cache ) while the other, release in March 2005 in Germany found removal of dental amalgam leads to permanent improvement of various chronic complaints in a relevant number of patients in various trials.14 Two recent randomized clinical trials in children showed no statistically significant differences in adverse neuropsychological or renal effects observed over the five-year period in children whose caries were restored using dental amalgam or composite materials, although one study could not rule out the possibility of a small adverse effect on IQ in children with amalgam. In contrast, one study showed a trend of higher dental treatment need later in children with composite, and thus, claimed that amalgam fillings are more durable. However, subsequent study published in JAMA cites increased mercury blood levels in children with amalgam fillings. The study states, "during follow-up mercury levels were 1.0 to 1.5 microg/g higher in the amalgam group than in the composite group." EPA considers high blood mercury levels to be harmful to fetus, and also states that "exposure at high levels can harm the brain, heart, kidneys, lungs, and immune system of people of all ages." Currently, EPA has set the "safe" mercury exposure level to be at 5.8 micrograms of mercury per one liter of blood. While mercury fillings themselves do not increase mercury levels above "safe" levels, they been shown to contribute to such increase. However, such studies were unable to find any negative neurobehavioral effects, and once again assured that amalgams are safe. |
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