As to noticing a difference, I'm afraid that there has been so much bakground chatter in my life that I can't say one way or another. And the value to me was to prevent it getting worse as the amalgams aged as well. I would do it again is the best I can tell you.

If you do it, find someone who knows what they are doing or you will end up taking on a whole new load of mercury. They should be talking in terms of a rubber dam or sheet across the back of your throat to catch anything that escapes, a positive air flow so that you don't breathe vapors, and breaking the amalgams as much as possible instea of drilling them away. Otherwise, look for another dentist.