You make a good point...

Following is a legal statement from the American Dental Association (ADA). The (red) emphasis I've provided will help you read between the lines. If you're a dentist, you should be outraged and withdraw your membership immediately.

"The American Dental Association (ADA) owes no legal duty of care to protect the public from allegedly dangerous products used by dentists. The ADA did not manufacture, design, supply or install the mercury-containing amalgams. The ADA does not control those who do. The ADA's only alleged involvement in the product was to provide information regarding its use. Dissemination of information relating to the practice of dentistry does not create a duty of care to protect the public from potential injury."

The Superior Court of the State of California
Case No. 718228, Demurrer (October 22, 1992)

from: http://amalgamillness.com