Yes, there are many people who have had root canals where the hole left behind is filled with amalgam then covered with either the crown or the filling. I think number 7 meant to imply that if your dentist uses amalgam fillings there is a good chance you have some lurking underneath there. I am part of a Facebook group for people trying to detox from this mercury toxicity, since I myself had 15 of them at one point, and I personally know hundreds of people this has happened to. It is inaccurate to say that no amalgam is used in root canals. Most of those people are even sicker because once the root is gone and mercury is in the hole where it used to be then it comes in direct contact with the tissue. Many of these people have very large infections at the site underneath what is left of the tooth.