Summary of the report. Mandate for inquiry

The expert group's tasks was to investigate whether recent scientific reports, particularly results published since the issue in 1991 of general recommendations by The National Board of Health and Welfare (SOSFS 1991:6), warrant revision of the standpoint adopted in the above recommendations.

Other scientific reviews on possible health effects related to dental amalgam

Since the issue of the general recommendations by the National Board of Health and Welfare, The World Health Organization has published a criteria document on inorganic mercury and The Swedish Medical Research Council has issued reports from a "State of the Art Conference" held in 1992. In Germany, The Ministry of Health, Bundesgesundheitsamt (BGA), released information in the form of a report on amalgam therapy in dentistry in 1992, and in January 1993 The Department of Health and Human Services (USA) published a report. All these documents address the issue of whether amalgam can have an adverse effect on human health. The expert group has scrutinized these documents. In no case have these expert reports been able to show that there are scientific grounds for allegations that mercury from dental amalgam has an adverse effect on general health.

Effects of mercury on different organ systems

The expert group has reviewed the literature whether mercury (Hg) - in this case mainly mercury from dental amalgam - has toxic effects on different organ systems. In summary, the available data indicate that exposure to low to moderate doses of inorganic Hg does not cause any functional disturbance of the human endocrine system. The expert group has found no support for the claim that mercury released from dental amalgam causes immunological disease or general immunological symptoms in humans, although in rare cases mercury can cause localized allergic reactions.

Scientific studies show that dental amalgam does not contribute to cardiovascular disease in women. There are no similar studies in men.

In chronic exposure to mercury vapour the most vulnerable organ is the central nervous system. It has been shown that dental amalgam fillings cause some exposure to mercury vapour, with subsequent uptake in the central nervous system. Normally the level of exposure is very low. The current scientific literature does not support an association between mercury exposure from dental amalgam and toxic effects on the central nervous system or the peripheral nerves. Nor does the literature support an association between low-level exposure to mercury and the development of degenerative neurological diseases such as Alzheimer‚s disease, Parkinson‚s disease or amyotrophic lateral sclerosis.

The kidneys are very sensitive to inorganic mercury. Subjects with multiple amalgam fillings have higher concentrations of urinary mercury than subjects without amalgam fillings, but the concentrations are generally much lower than the threshold values for renal damage. Subjects with multiple amalgam fillings who grind their teeth (bruxism) are exposed to higher levels of mercury, possibly levels at which some effect can be observed. This effect is, however, of little or no importance for general health. At present there are no studies indicating risk for serious renal dysfunction or renal damage due to release of mercury from amalgam fillings.

Many studies have investigated the possible association between the number of tooth surfaces restored with amalgam and various systemic symptoms, but no such association has been shown. There are, however, no controlled scientific studies clarifying the question whether there is a relationship between removing of amalgam fillings and reported effects on general health and the placebo effect in this connection.

According to the scientific literature, no adverse effects on foetal development or infant health have been shown to be associated with mercury vapour from amalgam fillings.

Psychosocial and psychiatric effects

It has not been shown that the psychic problems and symptoms attributed to amalgam fillings are due to direct damage by mercury or other components of the filling material. However, it is clear that in the heterogeneous group of patients with symptoms of ill health which they allege to be adverse effects of amalgam fillings, there are individuals with not only dental and other oral diseases but also systemic diseases and dysfunction, and as well a considerable proportion of psychic disturbances and psychosomatic overtones. It is therefore essential that these patients receive a thorough investigation by specialists from relevant medical and dental disciplines in order to provide adequate treatment.

Experience from medical centres working with these patients

Follow-up studies of large patient material show that many patients, in some cases the majority of subjects, have persistent symptoms and discomfort even after removal of amalgam fillings. It has been shown that the patients' so-called illness quotient (number of days on sick-leave or invalid pension) does not decrease after removal of amalgam fillings. The patient‚s problems have generally been attributable to diagnoses other than mercury poisoning. The expert group considers that these presentations and follow-up studies further support the view that there is no causal relationship between amalgam fillings and generalhealth.

Investigation on specific test methods for mercury exposure

Most of the patients with problems which they attribute to amalgam fillings have normal concentrations of mercury in blood and urine. Only isolated cases of raised mercury levels have been reported and these have generally been correlated with high consumption of fish (raised levels in blood) or bruxism (raised urinary levels). The practice of analysing mercury levels in biological fluid in investigation of "amalgam patients" should be restricted and limited to those cases in which there are basis for suspecting abnormally high exposure to mercury, e.g. in association with occupational exposure, high consumption of fish, or in cases of multiple amalgam fillings with signs of tooth grinding and/or clenching. he expert group has specifically investigated those tests which it is claimed can be applied to diagnose "amalgam sickness", namely the PIXE method to measure mercury in single blood cells, the so-called MELISA test using blood cells (lymphocytes) and a skin test in combination with a questionnaire, as proposed by Associate Professor Jan Marcusson of Huddinge University Hospital, Stockholm. Neither the PIXE method, the MELISA test nor the allergy test ad modum Marcusson can in the groups considered opinion be applied for individual diagnosis of alleged amalgam effect or mercury poisoning. Recommending amalgam removal on the basis of such tests is not in accordance with scientific evidence and established procedures. From toxicological and medical perspectives, themost important exposure to inorganic mercury from amalgam fillings occurs through inhalation of mercury vapour. In contrast to analysis of mercury in urine and blood, analysis of mercury in faeces cannot be used to determine either biologically significant exposure or risk.

Mercury exposure during amalgam removal

During removal of amalgam fillings, as in all other procedures involving amalgam, special precautions should be taken to minimize mercury exposure to both patient and dental personnel. A high volume aspirator and water coolant should always be used during polishing or removing amalgam: this results in a marked reduction in concentration of mercury in the atmosphere. In different contexts medication with antioxidants and vitamin E has been recommended. A review of the literature shows no prospective, controlled study of any pharmaceutical, or antioxidant, in which the effect of these substances in humans has been related to the mercury exposure during removal of amalgam fillings. Thus to date there is no scientific basis to support the claim that antioxidants and Vitamin E counteract the allegedly adverse effects of dental amalgam, with or without amalgam removal.

Conclusions

The expert group was directed to investigate whether the results of scientific reports published since 1991 warrant revision of the standpoint expressed by The National Board of Health and Welfare in the general recommendations issued in 1991. Scrutiny of the results of recent research, including material presented to the expert group by the Swedish Association of Dental Patients has not shown that mercury from amalgam has an adverse effect on health, with the exception of isolated cases of allergic reactions. It is essential that patients alleging ill health due to dental amalgam receive a thorough examination by representatives of medical and dental disciplines so that adequate measures may be taken to treat any diseases which might bediagnosed. The expert group has specifically scrutinized the tests which are claimed to be diagnostic for "amalgam sickness", in particular the PIXE method and the MELISA test. After assessing the available material, it is the opinion of the expert group that neither of these tests can be applied for individual diagnosis of alleged adverse effects of amalgam, or of mercury poisoning. There is thus no scientific documentation for recommending so-called amalgam removal on the basis of these tests. The material scrutinized by the expert group includes follow-up reports of various large patient groups. In many cases, and in some studies the majority of patients, symptoms and discomfort have persisted even after amalgam removal. Diagnoses other than mercury poisoning have in some cases explained the patient's symptoms. These reports further support the opinion that there is no causative relationship between amalgam fillings and general ill health. It is therefore the opinion of the expert group that there are at present no medical indications for recommending amalgam removal in order to relieve symptoms of general ill health.

This document was entered with the permission of Dr. Hans Sundberg, Swedish National Board of Health and Welfare by Prof. Douglas Bratthall

1994

Also make sure to read these books: Poison in Your Teeth: Mercury Amalgam (Silver) Fillings...Hazardous to Your Health! and Mercury Detoxification by Tom McGuire