Well i dont know, but I do know this. I swallowed some mercury during my last removal. The assistant didn't use the suction when she should have.

Well I got told it was no big deal, it would just pass straight through. I got so ill from that removal alone, I drove home with tremors in my lips and face and the change in my appearance was instantanous. I could not believe the change. I got gaunt in the cheeks, very pale, and began to get headaches and crying.

So much for the theory of it not being a problem!! If that were so, why do they use rubber dams to protect against swallowing the stuff???? Why do they handle it with so much care? lol, the contradictions are amazing.