Quoting:

> The debate over the safety and efficacy of amalgam has raged since time immemorial. In recent times, it has reached such a feverish pitch that it seems to drown out all sounds of reason. Amalgam has served the dental profession for more than 165 years. Incidents of true allergy to mercury have been rare and attempts to link its usage with diseases like multiple sclerosis and Alzheimer’s disease have not been significantly proven, although there may be some association between amalgam restorations and oral lichenoid lesions.

> Marshall, in his review on dental amalgam, summed it up appropriately: “if some reported values of Hg release are extrapolated to clinical life times, the entire restoration could lose its Hg in short time. For example, a 500 mg amalgam restoration contains approximately 200–250 mg of Hg, and the entire quantity of Hg would be lost in 10,000 days if the Hg was released at the rate of 25 ?g/day. This estimate of release is of the order of magnitude reported in some studies of vapour release”.

The real crux of the issue is that there are safer effective alternatives. So even if we call the risk "low," it is a needless risk. It only a matter of "when" not "if" these filings are against safety regulations.