Composites can be toxic, too, but I don't know much about those. I think a lot depends, like many things, on type of composite, individual sensitivity, and maybe even other factors. I had all porcelain crowns put on, after having a bad reaction to gold crowns (gold on the inside, where it adheres to the tooth) and having to have all those removed and then redone all over again with the porcelain. When my mercury doctor & I were trying to find out the reason for all the symptoms getting worse again almost as soon as the gold ones were put on, he had me touch a copper wire to the underside part of one of the crowns, to the small kind of edge of the tooth near the gum where a small amount of the gold was exposed. Apparently I wasn't grounded properly and there was a loud electrical popping noise and a jolting sensation that caused me to jump about a foot off the ground (figuratively speaking - in reality it was probably more like a few inches). That's when we knew -- in my case, anyway -- that there was a strong electrical component to the metals that was causing a lot of the problems -- we are bioelectrical beings, after all. And sure enough, once the gold crowns were removed & the ceramic ones put on, the symptoms abated again almost immediately, just like they had before when the mercury was taken out (there was about a 2-week period between when I had the amalgams removed & the porcelain crowns made with my teeth ground down and just bare - lots of eating through straws and sucking in my cheeks to avoid anything too cold hitting them!). The effects of the gold crowns were not as strong as the amalgams, but there's a lot more mass in the fillings than there is on the thin coating of gold on the bottom of the crowns. I probably never would have believed any of this if I hadn't experienced it first-hand. But that's exactly how it happened, as real as me sitting here typing this to you now. Two family members witnessed the gold electrical popping noise event, and of course many people, friends, colleagues, history of allergy docs, etc. witnessed the dramatic difference before & after having the amalgams removed. Caveat emptor when it comes to mercury amalgams, or any metal in the mouth at all.