Conducted trials and their conclusions

Two recent randomized clinical trials in children discovered 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 dental fillings, and thus, claimed that amalgam fillings are more durable. However, the other study (published in JAMA) cites increased mercury blood levels in children with amalgam fillings. The study states, "during follow-up [blood mercury levels were] 1.0 to 1.5 μg 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 μg (micrograms) of mercury per one liter of blood. While mercury fillings themselves do not increase mercury levels above "safe" levels, they have been shown to contribute to such increase. However, such studies were unable to find any negative neurobehavioral effects.

Active clinical trials awaiting results

The University of Bergen is currently running a clinical trial titled "Health Effects From Removal of Amalgam Restorations in Patients With Symptoms Allegedly Related to Dental Amalgam". Estimated Study Completion Date: August 2010.

Criticism of the clinical trials

In response to studies which assert amalgam safety, anti-amalgam groups, such as the International Academy of Oral Medicine and Toxicology (IAOMT), state that these studies are poorly designed and raise ethical questions. An analysis of the data collected during the studies showed that the authors of the studies ignored the drop in mercury excretion after two years in the urine in the children with amalgam fillings, even though the mercury exposure from amalgam remained the same or increased. This is explained in a response by Dr. Boyd Haley, to the 2006 publication, in JAMA, of the NIDCR-funded children's amalgam study. According to Haley, this is evidence that these children are losing the ability to excrete mercury with increased exposure. This observation points to a strong limitation in the use of mercury concentrations within urine as an indicator of mercury exposure from amalgam (and, potentially, as an indicator of mercury concentration within the bloodstream). However, this opinion doesn't stand with the results obtained from one of the two clinical trials conducted.

The American Dental Association (ADA)

The American Dental Association (ADA) has asserted that dental amalgam is safe since its foundation in 1859. In its advisory opinion to Rule 5.A. of the ADA Code of Ethics, it has also held that, "the removal of amalgam restorations from the non-allergic patient for the alleged purpose of removing toxic substances from the body, when such treatment is performed solely at the recommendation or suggestion of the dentist, is improper and unethical". According to the Boston College Law School study, "A dentist who is found guilty of violating the ADA Code of Ethics can be sentenced, censured, suspended, or expelled from the ADA" and the "ADA forbids its dentists from suggesting mercury removal under threat of license suspension". The same study pointed out that state dental associations and disciplinary boards have "not only adopted the ADA's position as a matter of routine" in proceedings which have sanctioned anti-amalgam dentists or stripped them of their licenses in California, Maryland, Arizona, Colorado, and Minnesota, but in many cases "the board members themselves often belonged to the ADA as well". A 2002 article in the Atlanta Journal and Constitution reported allegations by anti-amalgamists that the ADA had effectively imposed gag rules which forbade them from discussing their positions with patients. The Boston College Law School study also cites proceedings in which an Arizona dentist, "is facing sanctions for advocating alternative materials", a California dentist lost his license, "for running an advertisement entitled: "Mercury Emission from Silver Filings Unsafe by Government Standards", and a Maryland dentist, "was sanctioned for writing an article on dental amalgam removal". More recently, the ADA has entered into litigation "aimed at defending its reputation and discouraging further lawsuits by patient-plaintiffs against dental amalgam".

Removal of amalgam fillings

Some practitioners may also recommend that patients with amalgam fillings have them removed and replaced, particularly if the patient is experiencing the symptoms that they attribute to the use of amalgam. These professionals recommend that unprotected amalgam removal should be avoided even in routine dental procedures to avoid exposure to mercury vapor and amalgam particulate matter.

Consumer Reports magazine, among others, claims that the connection between many of these diseases and amalgam fillings is solely revenue generating propaganda. Consumer Reports told its readers on several occasions that "if a dentist wants to remove your fillings because they contain mercury, watch your wallet."

Trends in amalgam use

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 in developed countries, though overall amalgam use continues to rise worldwide. Given its superior strength, durability and long life relative to the more expensive composite fillings, it will likely be around for many more years to come.

Attempts in lawsuits

Organizations opposed to amalgam use, such as Consumers for Dental Choice, claim to have over 65,000 studies on file implicating amalgam fillings as the cause of a diversity of health disorders. These studies have been used in various lawsuits, and were the main contributing factor to the passage of Californian legislation concerning the issuing of warnings to patients about mercury, and to the federal bill introduced in 2002 proposing that amalgam fillings be made illegal after 2006.

Autoimmune disorders

Dental amalgam has been found to be a frequent contributor to oral lichenoid lesions and is possibly a variable associated with an increased risk of other autoimmune conditions such as multiple sclerosis, lupus, thyroiditis and eczema.

Health effects for dentists

There has been no evidence that dentists who are exposed to dental amalgam and vapor on a daily basis get mercury poisoning. Some studies have indicated that mercury from dental amalgam has mild effects on some dentists. Dentists in several large-scale studies performed multiple cognitive atests and, compared to a normal population, lagged behind in many areas. In one study this included 14% worse scores in memory, co-ordination, motor speed and concentration. The study did not demonstrate any link between mercury exposure and these lagging scores, however. A newer study also found a link between cognitive impairment (including mood) and dental work, even though "exposure among these dental personnel is not much greater than exposures to the general population through the dental amalgam in their fillings" as shown by urinary studies. Twelve of 13 symptoms were correlated with greater mercury exposure.

A study examining the health effects of mercury on dentists in the UK published in the Occupational and Environmental Medicine Journal concluded that 180 dentists had on average 4 times the urinary mercury excretion levels of 180 people in a control group. Dentists were significantly more likely than control subjects to have had disorders of the kidney or memory disturbance. No direct correlation between urinary mercury levels and the disability, however, was found. Urine testing is unreliable for showing lifetime mercury accumulation rather than recent exposure.

In the 2005 lawsuit Barnes vs. Kerr, the dentist David Barnes brought action against the Kerr Corporation, a major manufacturer of dental amalgams. This suit was originally decided in the Circuit Court for Bedford County and reviewed by Sixth Circuit of the United States Court of Appeals. Barnes argued that his alleged mercury poisoning was caused by exposure to toxic mercury vapors, and that Kerr Corporation's amalgams were the major source of this poisoning.

Barnes' suit alleged that his exposure came from three sources. The first was "mercury vapor and mercury contained in amalgam particulate inhaled when removing existing amalgam from the teeth of patients". The second was "contaminated office air due to a variety of sources, including mercury released during trituration of capsules, opening of triturated capsules, free mercury that may have leaked during transport, and particulate released into the office air during amalgam removal". The third source was "was mercury vapor and mercury particulate generated during the placement of new amalgams".

Barnes' office was found to be contaminated with mercury by the Tennessee Occupational Health and Safety Administration (TOHSA) , even after it had been thoroughly cleaned, and mercury droplets were found in the machine he had used to mix amalgam capsules. An industrial hygienist found that "89% of the surfaces in Barnes’s office still showed traces of mercury", even after two intensive cleanings.

Kerr Corporation argued that they had not manufactured a majority of the amalgams Barnes had removed, that the contamination of Barnes' office, "could have come from sources other than leaking capsules", and that Barnes could not have been exposed to mercury during the placement of amalgams because of the methods he used.

Kerr Corporation's amalgam capsules bore prominent warning labels in capital letters stating that they "CONTAIN[ED] METALLIC MERCURY" and featured a skull and crossbones next to the word "POISON". A detailed warning enclosed with the amalgam capsule described mercury as a "hazardous ingredient" and listed potential health hazards associated with exposure including nervous irritability, weakness, tremors, gingivitis, erethism, greying of the lens of the eye, nephrotoxic effects, and aggravation of kidney disorders. This full text of the warning read, "WARNING ... Alloy amalgam capsule products contain mercury. Since mercury is a potentially hazardous substance, proper care should be taken to prevent exposure to mercury. These preventative measures include the wearing of gloves, good ventilation, the use of an enclosed amalgamator, proper disposal of capsules once they have been activated and used, and the use of HGX or similar-type mercury absorbing chemicals in the event of spillage. Infrequently capsules may leak mercury and, as a consequence, the above precautionary measures should always be utilized".

The district court held that the testimony of Barnes' expert witnesses in support of "a strong minority view that dental amalgam containing mercury is both unreasonably dangerous and hazardous to human health" was admissible. The district court decided in favor of Kerr Corporation because Barnes had "not demonstrated that his injuries would have occurred ‘but for’ exposure to Kerr’s dental amalgam product". They also ruled that the numerous warnings provided by Kerr "more than adequate [because] ...[r]easonable minds could not differ as to their sufficiency". Barnes' suit against Kerr Corporation was dismissed because he had been warned that amalgam was poisonous and that its use could result in the contamination of his office, and because he could not prove that the majority of the amalgam which had contaminated his office had been manufactured by the Kerr Corporation.

Environmental impact

The WHO reports that mercury from amalgam and laboratory devices accounts for 53% of total mercury emissions, and that one-third of the mercury in the sewage system comes from dental amalgam flushed down the drain. 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, but in many countries it is not regulated, including the United States. 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. The environmental pollution of mercury imposes health risks upon the surrounding population; in economics this pollution is considered an external cost not factored into the private costs of using dental amalgam. Separators may dramatically decrease the release of mercury into the public sewer system, but they are not required in the United States.

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 US states.

The Association of Metropolitan Sewerage Agencies (AMSA) studied seven major waste-water treatment plants and found that dental uses were "by far" the greatest contributors of mercury load, on average contributing 40%, over 3 times the next greatest contributor. The EPA recognizes dental amalgam as a major source of the mercury in the water. The Western Lake Superior Sanitary District that dentists emit .1 grams of mercury per day per dentist. Based on this, dental amalgam contributes 14% of the mercury in Seattle and 12% of the mercury in San Francisco. 4% of the mercury in Lake Superior is believed to originate from amalgam. The National Association of Clean Water Agencies noted in a report that purification of mercury from waste water will impose a significant financial burden upon municipal treatment plants. Several other groups have analyzed mercury in waste water and concluded that it is a serious problem. Other studies have shown this to be a gross exaggeration. With respect to pollution in the United States, a study done in 1992 showed that batteries "accounted for 86 percent of discarded mercury and dental amalgam a mere 0.56 percent."

Available alternatives

According to the Consumers for Dental Choice, fully one third of the dentists in the US are currently 'mercury free'. Alternatives include composite resin (or "white") fillings, gold, porcelain, and glass ionomers. However, 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.[citation needed] Most of these materials, with the notable exception of gold, have not been used as long as amalgam, and some are known to contain other potentially hazardous compounds. This is why biocompatibility testing is recommended for all dental materials as per ADA/ANSA or ISO standards, and can be performed by specialized laboratories. 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". Teaching of amalgam techniques to dental students is declining in some schools in favor of composite resin, and at least one school, University of Nijmegen in the Netherlands, had eliminated dental amalgam from the curriculum entirely in 2001.

Notable critics of Amalgam fillings

Alfred Stock, a noted chemist, reported becoming very ill, and eventually tracing his illness to his amalgam fillings and the resulting mercury intoxication. He described his recovery after the fillings were removed and believed that amalgam fillings would come to be seen as a "sin against humanity." Hal Huggins, a Colorado dentist, is a notable critic of dental amalgams and other dental therapies he believes to be harmful; his views on amalgam toxicity were featured on 60 Minutes.

History

In 1840, the American Society of Dental Surgeons was founded by a group of dentists who met in New York city. It was the only national organization of dentists in existence at the time. Chapin A. Harris, the co-founder of the ASDS and the first dental school in the US, the Baltimore College of Dental Surgery, spoke of dental amalgam in his opening address: "It is one of the most objectionable articles for filling teeth that can be employed, and yet from the wonderful virtues ascribed to this pernicious compound by those who used it, thousands were induced to try its efficacy". In 1845, the ASDS had members sign a mandatory pledge promising not to use mercury fillings because of fear of mercury poisoning 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). 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.

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, the 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.

I wounder if you can share us this time ! let's forget about the previous one .. and begin together again !

Waiting for reactions !

By the way : the reference :
Wikipedia, the free encyclopedia

شكراً سجى .. ولا عليك بما يخص وقت الاستلام .. فهو ممتد حتى 2011.1.1 بإذن الباري

..........................



هذه لي .. إن شاء الله تعالى سأترجمها بأقرب فرصة!
السلام عليكم

بانتظار المشاركة من الجميع