Key Points about Amalgam Safety


Robert S. Baratz, M.D., D.D.S., Ph.D.
September 24, 2004

Composition

  • Statements that amalgam is 50% mercury are false because the original ingredients are modified during the setting reaction.
  • Dental Amalgam is the result of a series of chemical reactions among its components. The starting material consists of approximately 35-42% mercury plus an “alloy” of silver, copper, tin, and other minor components. The final product—called amalgam—is a completely different material that contains a variety of complex compounds. In one sense it is similar to mixed concrete. You start with cement, sand, stone and water. The final product is concrete. You can’t get the original components back without chemically decomposing it.

Safety

  • The word “safe” is a relative term and requires definition. Once one makes a definition of “safe” then one can measure a material or activity against this standard.
  • No study has shown any harm from proper use of dental amalgam in patients. Amalgam can be subject to fracture and pieces swallowed. These are not absorbed and pass through the GI tract. Amalgam has also been aspirated on rare occasions. No harm has ensued from the material itself. Amalgam has regularly been implanted into bone during surgical endodontics without any resultant harm. Occasional minor allergies have been reported. Virtually every dental material can give rise to allergies. Amalgam is not the most allergenic of dental materials.
  • No disease or illness has ever been associated with amalgam use in patients, or from occupational use by dentists, except for rare instances of allergies. Composite resins typically contain about twenty different organic compounds, some of which are highly reactive chemicals. However,  they are present in such small amounts that no evidence of harm has been found. In short,  there is no scientific evidence that any of the currently used restorative materials are unsafe when used for approved purposes.
  • Major reviews by the FDA, the National Institutes of Health, and the U.S. Public health service have confirmed the safety of amalgam. Major consumer and patient advocacy organizations—including Consumers Union, the National Multiple Sclerosis Society, and the Alzheimer’s and Related Diseases Association—have concluded that there is no association between amalgam and human illness.

“Toxicity”

  • Dose makes a poison. Even table salt can be poisonous. One can drown in simple water. No component of set dental amalgam is a known poison.
  • The ingredients of current amalgam are sold in pre-proportioned, sealed capsules. They are mixed before use. Neither patients or dental personnel are exposed to the ingredients before they are mixed. Even if the ingredients were released, the quantities are small and can be readily and safely handled without any risk.
  • Extreme heat and friction can decompose amalgam. This may occur during removal with rotary instruments. Proper cooling, vacuum, and ventilation eliminate any hazard.
  • Claims that amalgam contains organic mercury or is converted to organic mercury are false.

Clinical Issues

  • There is no benefit from removal of amalgam that is clinically sound and serviceable. No diseases are prevented or treated by such removal. Inappropriate removal is often accompanied with replacement with a more costly material without any clinical benefit, and often with clinical liabilities. Other dental materials are more subject to recurrent caries.
  • Inappropriate removal of amalgam exposes a patient to an unnecessary procedure. The risks of removal include: complications from local anesthetic, potential for laceration from rotary instruments, possible exposure to bacterial and viral pathogens, potential for penetration into the pulp chamber, preparation that enlarges a cavity and weakens tooth structure, potential for thermal and chemical insult to vital dental pulp tissue, and potential for aspiration.
  • Patients depend on their dentists for reliable, honest, and legitimate information and treatments. Patients depend upon the dental boards to enforce these standards. Inappropriate removal is often a result of coercion by dentists who engage in fearmongering, innuendo, and conveying false information for personal gain.
  • Dentists who make false claims about amalgam safety create unnecessary patient anxiety, and undermine confidence in the profession. In some jurisdictions this would be considered unprofessional conduct.
  • Dentists are free to use whatever material is clinically appropriate in their judgment. No dentist is required to use amalgam. However, selection of a material should be based only on its known clinical properties and performance for the particular placement situation, coupled with the needs of a patient. Dentists who exclude any material from possible selection for a given restoration on the sole basis of unsupported conjecture or belief cannot be providing optimal services for all of their patients. Such dentists may be denying a patient the benefits of a material that is most suitable for that patient’s needs. Such denial in some jurisdictions would be considered unprofessional conduct.
  • Dentists who purport to “diagnose” or “treat” “heavy metal toxicity”, or who test patients for heavy metals by any means are not practicing dentistry. These activities fall outside the scope of dental licensure. Any dentist who believes a patient requires diagnosis or treatment for any medical condition outside of the scope of dentistry is obliged to make a referral to a physician or other health professional as appropriate. Failure to make such a referral is considered negligent practice in most jurisdictions.
  • Dentists who advertise they are “mercury free” are implying that there is a problem with use of dental amalgam. Such advertising may also be considered false and misleading. These dentists are not “mercury free.” Water used in lavage and air in the office contain mercury. Removing amalgams generates some mercury-containing waste materials.
  • Studies have shown that under some conditions it is possible that small amounts of mercury may be released from the surface of amalgam into the oral cavity. Much of this is quickly inactivated by saliva. There are no data to show that this mercury is absorbed into the body in a form that may be harmful. In fact, there are no data to show that it is absorbed at all. Estimates of the amounts of mercury that may be released place these in the same range of possible exposure as amounts from food and water in a regular diet. These amounts are about a hundred times less than those to which industrial workers can be regularly exposed without any adverse health consequences under current regulatory standards.
  • Professional licensing boards have a duty to protect the public by making and enforcing practice standards based solely on scientifically gathered objective evidence.

This page was revised on September 24, 2004.