Precautionary advice for Dentists / Pregnant Women
Precautionary advice for Dentists and Pregnant Women
The Ministry of Health is advising dentists to avoid using or removing any tooth filling material in pregnant women where clinically reasonable.
"Internationally recommendations concerning use of amalgam in pregnant women are becoming more cautious. In line with this, the Ministry of Health has changed its policy on amalgam dental filling materials to protect women from any theoretical risk," said Dr Colin Feek, the Ministry's medical chief advisor.
This advice was circulated to all dentists in March.
The change in the Ministry's stance has come about following two overseas reports: The Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment's statement on the toxicity of dental amalgam (December 1997); and A European Commission report on Dental Amalgam (December 1998).
These reports concluded that there is no evidence of risk of systematic toxicity from dental amalgam, but recommended caution in putting in or taking out amalgam fillings in pregnant women. Accordingly, the British Department of Health changed its policy advice in April 1998.
Last year the Ministry of Health began discussions with Australian health authorities about similar advice and a consistent approach between the two countries.
These discussions are continuing, but the Ministry of Health this year chose to introduce the new advice for New Zealanders.
"Mothers can be reassured that there is no evidence of harm to babies from treatment with dental amalgam during pregnancy," Dr Feek says.
"However, it is generally accepted that women should avoid unnecessary medical interventions during pregnancy in order to minimise possible risks.
"So the Ministry's advice to dentists is that it would be wise to avoid elective dental procedures including the placement or removal of any dental filling in pregnant women."
The Ministry of Health commissioned an extensive review of dental amalgam and human health in early 1997 which found that no new scientific evidence has emerged to indicate present or future public health problems associated with the use of amalgam in dental fillings.
This review concluded there is scant evidence to support either a link between the health of individuals and the micro-leakage of mercury from their dental amalgams, or that removal of dental amalgams has beneficial effects on health. It recommended that amalgam still be used but with informed consent.
Alternative filling materials are more technically demanding to place, more expensive and often not as durable. All of these are yet to be fully assessed for their long-term safety.
The Ministry of Health continues to encourage research on dental amalgam and human health that is practicable in New Zealand and to monitor reports of possible harm to health from mercury in amalgam dental fillings.
Ministry of Health policy statement on Amalgam and other Dental Filling Materials: July 1999
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.
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.
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.
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 fetus 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.
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.
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.
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.