I have been severly ill for over 17 mths. The symptoms have been debilitating. I will spare all the details I had many doctors and ND tell me that they have seeb people disabled from infected root canals and mercury fillings. I think everyone needs to get educated on this subject, My MD order the Clifford Test (metals and chemical ) allergy test. He told me that before having any fillings put in I needed to have this test, I found out I'm deathly allergic to mercury, formaldehyde and tons of other things. Apparently some dentists in the US once used Sargenti Paste ( paraformaldehyde) in fillings this is really dangerous stuff DO NOT ever have these put in your mouth I think they are using it in the UK. This stuff was in a root canal that was just extracted and I'm having all the mercury removed and one more root canals extracted I believe this these things can be making people deathly ill.