Sean, if your dentist took good x-rays afterwards, there shouldn't be any problem.

I would get a metallic taste in my mouth occasionally, but only from certain supplements...I think thats normal with mercury poisoning and not something you should worry about.

I did do 18 rounds of ALA w/ (8 were w/ DMSA) that tiny speck in, and I don't think it hurt me, but it could have still been holding me back.