Dentists have been polluting the environment with dental mercury amalgam waste for over 100 years. All the while oblivious to the fact they were contaminating the environment with mercury or denying they were the most significant source or mercury pollution.
Now with the advent of the environmental movement in full swing and the EPA soon to issue a mandatory amalgam separator regulation for dentists, Michigan has allotted $270,000 to give to dentists to help them stop contaminating the environment. Michigan dentists must have a heck of a lobbying organization to pull off such generosity from a state such as Michigan with all of its financial woes.
interesting facts about ADA lobbying from SourceWatch.org
According to a January 2006 search of the online database Lobbyists.info, the ADA lobbies on "Environmental / Superfund" and health issues. It has a political action committee, the American Dental Political Action Committee, whose director is Francis X. McLaughlin. ADA's Washington DC office has at least 13 staff people, including three Congressional lobbyists: Michael A. Graham, William Prentice and Judith C. Sherman. According to the Center for Responsive Politics, the American Dental Political Action Committee gave $1,481,504 to federal candidates in the 2004 election cycle, 40% to Democrats and 60% to Republicans. 
ADA also hires outside counsel and consultants, including Larson Dodd Stewart & Myrick and Wexler and Walker Public Policy Associates on health issues, and Pepper Hamilton LLP on environmental / Superfund issues, according to Lobbyist.info.
According to the Center for Public Integrity, the ADA spent $2,520,000 on lobbying from 1998 to 2004. Over that same period, the ADA was represented by WPP Group plc, Larson Dodd Stewart & Myrick and Baker & Hostetler. 
and Public Relations
ADA has also hired the New York-based PR and marketing firm Van Vechten & Company.  According to the firm's webiste, they won a Presidential Citation for their work for ADA.  The firm's website briefly describes their ADA work: 
- What did we do for the ADA? We fought false information about the supposed risks from fluoride. We fought false reports about intensified risks from amalgams and the mercury contained within fillings.