San Diego. Dementia is a problem that has been associated with dental amalgam that contains mercury. As E Camiade and his colleagues from the University of Bordeaux, Bordeaux, France point out in their presentation at the IADR in San Diego, 2011, “the search for risk factors for these neurodegenerative diseases is abundant in the literature”.
However, as they note, among these factors, the mercury in dental amalgams has been evocated without clear scientific evidence. Given this, the objective of their presented study was to assess the relationship between mercury contained in dental amalgams and the occurrence of dementia through a systematic literature review.
To assess the potential relationship they instituted a systematic search on articles referenced in the PubMed electronic database as of January 2010, performed using key words chosen among Mesh terms and free words to avoid missing relevant articles. The inclusion criteria included articles written in French or English and articles mentioning mercury from dental amalgams and dementia or impaired cognitive function. These were applied using a selection grid. Data were extracted from articles by two independent persons using a standardized form created for this study and synthesized.
The authors state that of 146 references, only 19 articles published between 1989 and 2008 were selected and analyzed: 2 randomised clinical trials, three prospective cohort studies, three retrospective cohort studies, two case-control studies and nine cross-sectional studies. Most of the articles measured mercury exposition through urine concentration. Most articles did not show any relationship between mercury from dental amalgams and the onset of neurological problems. Only three cross-sectional studies found an association (including one related to professional exposure), but these studies had methodological limitations.
Unfortunately, a Meta-analysis could not be performed due to the variety of study populations and neurological symptoms assessed. They conclude that although mercury is a known neuro-toxic, epidemiological arguments are not sufficient to state that this metal used within dental amalgams is a risk factor for neurological diseases. However, they also state that further research with solid epidemiological design is needed to fully assess the possibility of risk.