I am hoping to have my amalgam fillings safely removed. Which is likely to be more important to minimise mercury absorption: the use of a rubber dam or breathing via a separate nasal air supply. I have consulted two mercury free dentists: one offers the dam, the other the nasal air supply. Neither offers both. Is anyone aware of any scientific research which has measured blood mercury levels before, during and after amalgam removal using different removal methods and precautions?

Don't know of any studies of that kind.

Given the choice, I'd have to know what other forms of protection are provided.

For example, air filtration pulling air away from the face (like I had) would alleviate some of the need for an air supply while activated charcoal and chlorella under the tongue would alleviate some of the need for a dam.

Be sure you don't just accept what they are offering without first asking if they would be willing to provide both.