Authors' objectives:

Objective was to carry out a health technology assessment (HTA) of the health effects of replacing amalgam fillings in persons on the suspicion of adverse health effects from amalgams.

Authors' recommendations: Conclusions and Results Fifteen clinical studies and two experimental studies were finally evaluated. The study design vs patient series ranging from pilot studies of ten persons participating to 142 patients. The majority of identified studies of sufficient good quality on the health benefit of amalgam removal are concentrated on oral lichenoid lesions. The 13 studies on oral lichenoid lesions (OLL) and oral lichen planus (OLP) indicate OLL to be contact dermatitis. The diagnosis was in general based on clinical examination and patch test and sometimes biopsy. In nine of the follow-up studies, complete healing or partial healing were achieved in 72-95 % of the patients. Lesions extending beyond the contact area or not in contact with amalgam showed varying results. The results on OLP were weaker than for OLL. Most studies used a patch test as a diagnostic tool. Two studies followed both patch test positive and negative patient groups. In one study the groups were not different, and in the other the degree of healing was less than 50 % and the two groups varied. A third study showed complete or partial healing in 29 % of the patients despite not having removed the amalgam fillings. An immunohistochemistry study showed the reaction in OLL to have great similarities to contact dermatitis. Patients often report multiple adverse health effects. Norwegian experience from the Dental Biomaterials Adverse Reaction Unit showed that the patients' intensity in local and general symptoms was reduced after replacement of dental materials, but not to the level found in a comparable group in the general population. No studies showed improvement in specific somatic diseases after replacement of amalgam fillings. These patients present themselves with complaints that can be considered to be of psychosomatic nature. These complaints are shared with other disorders. Any relevant studies of satisfactorily study design concentrating on using psychological tests when studying the effect of amalgam removal, could not be identified. The quality of the identified studies is low, regarding the effect on health problems believed to be relieved by amalgam removal. The main results of the synthesis of the study results are: 1. A great majority of oral lichenoid lesions in contact with amalgam fillings completely heal or improve after removal of amalgam fillings. 2. Lesions extending beyond the contact area, or not in contact with amalgam fillings, show little or no effect on healing after removal of the amalgam fillings. 3. The intensity of oral and general symptoms associated with amalgam fillings was reduced after removal of fillings but remained above the level observed in a representative control group. 4. After removing the amalgam fillings the mercury level in urine and blood temporarily increase before being reduced to an acceptable level. 5. Amalgam removal in healthy subjects was shown not to affect the kidneys as measured by the glomerular filtration rate. 6. Studies of sufficiently good scientific quality observing a reduction in signs and symptoms of general disorders after the removal of amalgam fillings, were not found. Further research/reviews required Randomized clinical trials to study the effect of amalgam removal are unlikely to be performed as double blinding to the effect of treatment is impossible. Amalgam fillings are already to a great extent being phased out.

Authors' methods: Overview

Project Status: Completed

URL for project: http://www.nokc.no

Year Published: 2006

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Norway

Organisation Name: Norwegian Institute of Public Health

Contact Address: Universitetsgata 2, Postbox 7004 St. Olavs plass, NO-0310 Oslo NORWAY. Tel: +47 23 25 50 00; Fax: +47 23 25 50 10;

Contact Name: Berit.Morland@nokc.no, dagny.fredheim@nokc.no

Contact Email: Berit.Morland@nokc.no, dagny.fredheim@nokc.no

Copyright: The Norwegian Knowledge Centre for the Health Services (NOKC)