Sorry for the downvotes. I received chelation therapy after years and years of very strange accumulating issues that some day crossed a threshold where they could no longer be ignored. I had actually not seen that coming and called myself healthy, the human brain is extraordinarily capable of ignoring obvious problems. When I was forced to acknowledge that not all was well my world fell apart. Long story short, I found the problem after some searching. Mercury was high both in hair and in urine - I was lucky. Normally chronic exposure is next to impossible to show via such tests. After chelation mostly with DMPS, later also lots of DMSA I achieved miracles. For exanple, a double-sized right thyroid with a nodule became normal and the nodule disappeared. That condition had been there for at least 25 years (first diagnosis). It disappeared within a few weeks, after the 4th or 5th DMPS treatment the tissues surrounding that area were very active, I knew there was something going on. So I went to the endocrinologist again who did the ultra-sound twice because he did not believe it. That is just a single example of many, from psoriasis (gone) to warts on the feet (gone), eye problems (gone), never-ending colds (for months!) that had gotten worse and worse over time, and a long list of other problems.
How do I know it was the amalgam fillings? Because that was my only exposure, and because it turned out my jaw bones were very damaged - exactly were there had been amalgam fillings. It was discovered not by x-ray, several OPGs never showed anything. But when I was to get an injection into the buccal mucosa the needle went right into the bone (that's really not supposed to happen, you can't penetrate bone with a small needle used for a mucosa injection). The doctor checked and this happened in all the places where I had had amalgam fillings. He then injected DMPS in those places. A year later, and after the jaw bones had been very active (but in a positive way) the needle didn't go in anywhere any more. To this day there is (decreasing) activity in my jaw bones, and I still take chelators that have an effect right there (jaw bone).
But please, go ahead and downvote anyone who says something about amalgam fillings. I actually have a background in medical topics, from anatomy, physiology to (of course) bio chemistry, and I read quite a few studies. The lead situation was so bad that politicians actually went to action to do something about it, worldwide. Mercury is far more toxic than lead (and, according to some LD study I once found on PubMed, together about a thousand times more toxic than either lead or mercury alone). Yes, pieces of amalgam are not the problem, they go right through. And as others have said, insertion and even more so removal - with a drill creating heat which creates vapor (no matter how much you cool with water, by then the vapor already exists) - are the worst parts. I had had a few fillings removed while I was a student. Only recently, two decades later, did I connect the dots, why back then I had a huge "almost asthma" allergy almost overnight, as well as huge problems finding sleep, strange thoughts, and big problems with some joints that didn't seem to have any observable reason. The removal was without protection, the removal of the last fillings a few years ago, when I hoped I had found the problem (I did not know, amalgam removal and chelation was an experiment because I could not find anything else, and boy was I proven correct), was with good protective measures that I think worked (I didn't get worse then I already was at the time).
Here is something to consider: What happened when I started DMPS chelation was something that according to doctors doing that kind of treatment is not uncommon, so much so that I was told that might happen before it happened. The initial values went down quickly and linearly - but after a few DMPS treatments my symptoms suddenly jumped. Turned out that the amount of excreted mercury had also jumped (tripled). From then on my body became "active". All kinds of crazy stuff happened, for a long time (it's still not quite over in the jaw area). It seems that the body is overwhelmed at some point and is no longer able to excrete everything. Maybe the spikes of insertion and/or removal of amalgam fillings contribute, too much at once. After the first year I took chelators because it still helped, but it was no longer necessary for excretion, my body had become pretty active. Maybe somebody whose body can deal with the spikes, or who never experiences them, has less trouble continuously getting rid of the mercury that is released from the fillings.
Sooo many questions, and I made soooo many interesting observations. Too bad it's impossible to talk about it, even anonymously on the Internet, because for some reason this topic raises the emotions of sooo many people. That the subject is present on so many websites of the esoteric kind is because it's next to impossible to talk about it in normal circles. My insurance always paid every little thing, even the most stupid and ridiculous and useless stuff - but when I finally send them a bill that mentioned "mercury" and "DMPS" (chelator) they suddenly refused. IT was a trigger word. They had paid for dozens of doctors (that one year when everything escalated, I went to many doctors with the many issues I had, from gastroenterologist to psychologist), now, the one thing that actually worked, and which was very cheap(!), they refused. It's insane. Same here - somebody mentions the trigger words (mercury, amalgam), the comment is voted down immediately. By whom actually? Are there so many prominent toxicologists reading this?
I don't think so. Even a normal MD would not know much about it. I've actually seen this: When I go to a talk from a doctor specialized in lung disease and someone in the audience asks about something not the lung the doctor is very careful not to say anything, because it's not their specialty. Strange, everybody (including non-doctors) has a strong opinion when it comes to the subject of chronic mercury poisoning through amalgam fillings.