So what about the regular “incompetent” dentists who sit right above their patients and drill out old amalgam fillings all day? They’re using an air-driven, water-cooled high speed handpiece to do so. They will always at least be using a local high volume evacuator for suction. If the amount of aerosolized mercury from the removal of these fillings is of clinical significance, we should see those regular dentists develop some sort of illness (neurological, neuromuscular, immune) at a significantly higher rate than either the general population or than the “competent” dentists who don their space suits and respirators and use their special filters. Maybe they do... but I certainly haven’t seen it be an issue. Seems like a great marketing strategy to me- tell everyone that their existing work is poisonous so they’ll pay a boatload of money for new composite fillings (look up BPA in composites if you’re bored), e.Max or zirconia crowns, or porcelain implants (what’s the problem with medical grade titanium?). Some people possibly benefit from the removal of old silver fillings. Those people probably have a hypersensitivity to one of the ingredients in the fillings. Many include nickel... and 10% of women have a nickel hypersensitivity. Some people had shitty root canals done with insufficient obturation or missed canals (it’s always MB2) or developed a vertical root fracture. But I highly doubt the vast majority of people benefit from having all of their old work replaced, at great cost.