You can see on the left photo that we took out the 20 plus year old silver fillings which are 50% mercury-30% silver-12% copper-and the rest zinc and tin! This 32 year young patient had the older technology "Mercury-Silver" fillings. They were clearly wedging the tooth apart! There was a "Black Crack" forming at the bottom of the filling. It was a good thing we replaced it with a tooth colored "Adhesive Dentistry" filling before we wedged a crack down to the nerve and caused a root canal!