You are not going to believe this but I never thought of this as well. I just thought nothing of it. But I have two fillings in my mouth. Some tooth number on the top rt and lt sides. One of the fillings fell out and I accidentally swallowed it,the other is inflammed and constantly irritates me. About the same time the filling fell out I got the dizziness and lightheadedness and vertigo. I don't know if it was a coincidence because I also had fluid in the ear after that as well as an infection. However I do know that some people do have reactions to the metals AND the contents of the packing material, in fact some people get poisining which has lead to several cases of MS, multiple sclerosis. Yes this is in fact true! I couldn't believe it myself, but there is an institution that deals with that particular problem. Ask to go for either mercury and lead levels of your blood. If they are increased that will lead to weakness and dizziness. Good luck, god bless.