I worked in an office here in AZ for 2 years that had a Biological Holistic Dentist in the same building. I spoke with him often about his beliefs, ideas and theories regarding not only amalgam fillings, but also root canals. Whenever he would remove amalgam (silver) fillings, he would use an IV and gas masks. Totally weird. He was an extremist and an activist with regards to his theory on the danger of the mercury of the amalgam fillings and the potentially harmful effects of doing a root canal. He would just pull the teeth, rather than do a root canal, and make a fixed bridge.
I believe he is one of about 6 dentists in the Phoenix metro area that practice this. All I can say is that his patients were wackos and he had a lawyer on hand everyday due to the lawsuit that have been filed against him. Essentially, what he practices is not in accordance with the dental board.