chakka35, I'm very grateful that you've raised this point. I'm afraid that there's a popular misconception in society that because mercury is insoluble (some regard it as inert) and is used in tooth fillings that it means that mercury is non-toxic. This is not the case. Elemental mercury is very poisonous in its own right.
To illustrate the point, when someone tells me that mercury is non-poisonous, I always suggest that they Google the phrase "as mad as a hatter". The phrase is usually attributed to the time when workers used to impregnate fur and felt with mercury salts and mercury itself in poorly-ventilated workshops during the manufacture of hats. As Mercury is an accumulative poison, many workers succumbed to mercury poisoning with symptoms such as uncontrollable trembling, slurred speech. teeth loosening, depression, anxiety and personality changes.
The following Oxford University link outlines the hazardous nature of mercury and is derived from a typical supplier Material Safety Data Sheet:
http://msds.chem.ox.ac.uk/ME/mercury.html