The Amalgam Debate

The dental amalgam controversy is a debate over the use of mercury amalgam as a dental filling. The concern centres on the long-term health effects associated with constant mercury exposure, particularly as a potential cause of chronic illnesses, autoimmune disorders, neurodegenerative disease, birth defects, oral lesions, and mental disorders.
Scientists agree that mercury amalgam fillings expose the bearers to a daily dose of mercury, but different studies have concluded that this exposure is very low and the effects of this exposure are disputed.
Currently dental amalgam is approved for use in most countries, although Norway and Sweden are notable exceptions.
Anecdotally, people who believe amalgam fillings are affecting them and have had them removed believe they are healthier in general and have more energy.
Let’s look at the debate:
The World Health Organisation (WHO) notes that exposure can be greatly increased by personal habits such as chewing gum and cites a report which found a five-fold increase in mercury levels after chewing, eating or toothbrushing. They report that amalgam is estimated to contribute 50% of mercury exposure in adults.
A Swedish study (Department of Environmental Hygiene, Karolinska Institute) of autopsies examined the mercury levels in brains and kidneys and found a strong correlation with the number of amalgam fillings.
A German study (Medizinischen Institut für Umwelthygiene, Heinrich-Heine-Universität Düsseldorf) found that mercury urinary excretion was significantly higher in those with mercury amalgam fillings.
Various diagnostic methods exist to detect the level of mercury in the body including blood tests, urine tests, stool tests, saliva tests, hair analysis and others. Opinions differ on which of these tests, if any, is the most accurate, although mainstream scientific research tends to place the most weight on chelation urine tests or stool tests when trying to assess chronic levels, or on blood or urine tests when trying to assess recent acute exposure.
None of these tests can link mercury levels to dental amalgams for methodological reasons, except (a) on an epidemiological scale or (b) through measuring levels before and after dental work. Studies have investigated both angles and results have differed, fuelling the controversy since the scientific data remains inconclusive and has not yet proven either safety or danger.
Scientific studies have come to opposite conclusions on whether the mercury exposure from amalgam fillings causes health problems.
In New Zealand 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.
The NZ Ministry of Health’s latest statement on amalgam was on June 10 this year. Then Dr Robin Whyman, chief dental officer, said the Ministry of Health’s position on the use of amalgam for dental fillings had not changed.
“Despite some recent American media reports on the use of amalgam fillings, our advice remains unchanged and is very much in line with information currently provided by the American Food and Drug Administration (FDA). Despite some claims that dental amalgam has been shown to adversely affect the health of pregnant women and of younger children, the FDA have actually said that their recent advisory panel did not believe there was enough information to answer that question at that time and the FDA is now undergoing a further process to look again at the scientific literature,” Dr Whyman said.
Dentists who advocate the use of amalgam point out that it is durable, cheap and easy to use. On average, resin composites last only half as long as mercury amalgam, although more recent studies find them comparable to amalgam in durability and dental porcelain is much more expensive.
However, the gap between amalgam and composites may be closing.
Further concerns (Journal of Materials Science 2004) have now been raised about the endocrine disrupting (in particular, oestrogen-mimicking) effects of plastic chemicals such as Bisphenol A used in composite resins.
Dr Whyman said dental therapists obtain written or oral permission from parents or caregivers before carrying out work on children and it is usual for dentists to discuss treatment options with their adolescent and adult patients.
For further information the FDA website features a question and answer section on dental amalgam www.fda.gov/cdrh/consumer/amalgams.html.

Resources: NZ Ministry of Health, Wikipedia – Dental amalgam controversy.