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Safety Information

Revised: 31 December 2012

Medical Device Safety Issues

Amalgam and other Dental Filling Materials

Background

The Ministry of Health continually monitors the international literature for reports of harmful effects to health from the mercury in dental amalgam and from other dental filling materials. In 1998 a report Dental Amalgam, was published by a Working Group for the European Commission (EC). This report concluded that the mercury from dental amalgam will not cause an unacceptable health risk to the general population. Local reactions to dental amalgam and other dental filling materials do occur but are relatively rare. The EC report stated that there was no need for clinically satisfactory dental amalgam fillings to be removed except in cases of a confirmed diagnosis of allergy to this material. A February 1999 report Dental Amalgam and Mercury in Dentistry, was published by the Australian National Health and Medical Research Council. This report concluded that dental amalgam continues to be a useful filling material and stated that "while low levels of mercury are released from dental amalgams, there is no convincing evidence of adverse health effects except for rare cases of contact hypersensitivity".

Benefits and risks

All medical and dental procedures have benefits and potential risks. Tooth restoration with dental amalgam is no exception. Amalgam remains an important filling material in dentistry although its usage is decreasing as tooth decay declines and the quality of other materials improves. These other newer filling materials are more technically demanding and expensive than amalgam and most are not as durable in some locations in the mouth. The newer filling materials remain to be fully assessed for their long-term effects on health. For conventional dentistry amalgam remains an affordable material for routine tooth repair.

Mercury absorption

Studies show that small amounts of mercury vapour from amalgam fillings are partially absorbed into the blood. Release of mercury vapour is increased by chewing food and grinding teeth, and when amalgam fillings are placed and removed. The acceptable, safe or tolerable level of total mercury exposure - from amalgam, diet and other sources - is still debated medically and scientifically.

Most medical and scientific opinion considers that exposure of the general population is within safe limits, others promote the view that mercury in amalgam fillings can adversely affect the health of some individuals.

International view

Some countries have restrictions on the use of amalgam as a dental restoration (Austria, Canada, Germany and Sweden) because of wider environmental effects of mercury or the possibility of adverse affects on some individuals even from low mercury intakes. In April 1998 the United Kingdom Department of Health issued a media statement advising that it was prudent to avoid the placement or removal of amalgam fillings during pregnancy until appropriate research data on its safety was available.

Ministry of Health Policy

The adult population

Most New Zealanders more than 30 years old, have or have had multiple dental amalgams. Despite widespread use of amalgam for many years there is no convincing evidence of adverse health effects. Local reactions to dental amalgam and other dental filling materials do occur but are relatively rare. These cases are generally contact hypersensitivity.

Dental fillings and pregnancy

Women of childbearing age should maintain good oral health. There is no scientific evidence that the placement or removal of amalgam fillings during pregnancy is harmful. It is prudent however, during pregnancy to minimise health interventions involving exposure of the foetus to foreign substances, including dental materials. Therefore, the Ministry of Health considers that it may be prudent during pregnancy to avoid, where clinically reasonable, elective dental procedures including the placement or removal of any filling material.

Children

The Ministry considers that the best strategy to reduce the potential risk from dental filling materials is through the prevention of dental decay. The most effective methods to achieve this are the fluoridation of water supplies and the use of fluoride-containing toothpastes and this is resulting in significant reductions in dental fillings.

There is no scientific evidence that dental amalgam or other restorative material when used in children is harmful. There is, however, increasing use of non amalgam materials in children. It should be taken into account that alternative materials may require more frequent replacement and less is known of their long-term effects on health.

Replacement of amalgam

The Ministry considers that widespread replacement of amalgams without other clinical indications by alternative filling materials, which are less long-lasting and more expensive cannot be justified on the basis of presently available clinical and scientific evidence.

The Ministry does not recommend amalgam removal or replacement for health reasons except where an individual has an allergy or hypersensitivity reaction to amalgam. Allergy or hypersensitivity reaction to amalgam is localised and relatively rare.

Informed Consent

Patients should be informed of the comparative risks and benefits of amalgam use when compared with other filling materials before they receive any restorative material or treatment. This is an obligation under the Code of Health and Disability Services Consumers’ Rights. It is recognised that there are limitations on the information available on all dental filling materials. Patients should also be informed of the international discussion on issues involving dental filling materials. The Ministry considers the best way to do this is through informed consent in selecting the appropriate filling material.

Monitoring

The Ministry of Health will continue to monitor the international scientific literature for reports of possible harm to health from amalgam and other filling materials used in dentistry.

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