My dentist did not use a rubber dam for amalgam removal, but a suction device called 'clean-up' (I think). This was placed over each tooth as he drilled, and it sucks up the vapour as it is released. My dentist said he did not rate rubber dams, as it was likely that mercury particles would fall down the side. I can't tell if I was exposed to more mercury vapour than I would have been with a rubber dam, and I was pretty sick anyway.

Certainly, the procedure without a rubber dam was much more comfortable - they can be very difficult to get on properly.

Check what the dentist is using - if he is using the suction device you won't need a rubber dam. Oxygen supply is good in all cases.

Best
Nicola