Thank you for sharing your experience and the follow up.
I looked up a dentist from the mercury free web site for my area, Portland, Oregon. This dentist's site reiterated that mercury was safe.
I think that the dentist on this mercury free site might be conventional is worth knowing. Although a practitioner may claim to be on the cutting edge, he might just want to make a buck.
Working with a practitioner who holds more conventional beliefs about health than I has proven to be disappointing in my experience and can end up being a waste of time or even feel frustrating.