False Professionalism and Economic Self Interest.

Increasing cynicism with age, to be sure, but I don't believe for a second that the ADA has anything but their own self serving economic interests, and their sense of professional "aren't we special" ego, in mind.

Reason Magazine - What Are You Smiling At?:

"...Some 60,000 indigenous Alaskans living in villages accessible only by plane, boat, or snowmobile received little dental care until the Alaskan Native Tribal Health Consortium decided to break a few rules. Following a model that is popular in Canada, England, Australia, New Zealand, and 42 other countries, the consortium sent tribal members to an accredited two-year dental program in New Zealand, where they learned how to fill cavities and clean and pull teeth.

Upon completion of the program, the members returned to their villages as certified dental therapists, capable of providing basic dental services. The therapists have since helped to bring down a rate of tooth decay that is almost three times the national average. But their efforts were nearly undone by the American Dental Association (ADA), which objected to anyone other than a licensed dentist conducting "irreversible dental procedures," such as pulling teeth and filling cavities. By the ADA's standards, a licensed dentist is one that has completed an undergraduate degree, a doctorate of dental medicine, or a doctorate of dental surgery, and has passed a statewide exam.

...The case received little national attention until the New York Times' Alex Berenson wrote in April that "dentists in private practice consider therapists low-cost competition" because they are only paid "one-half to one-third" as much as licensed dentists. Current ADA President Mark J. Feldman responded a month later in a letter to the Times, denying that the ADA objected to the Consortium's "experiments" out of its own "financial self-interest."

...This wasn't the only time the ADA has attempted to block a newcomer to the dental market. In December 2007, another New York Times reporter, Ian Urbina, wrote about the work of denturists. Denturists develop and install dentures and replace teeth; their inexpensive services are changing lives for the better in Kentucky, where residents, like indigenous Alaskans, suffer from tooth decay at a rate that is much higher than the national average.

...Despite the ADA's best efforts at controlling the cost of dental care, the tide may be turning. In May, reports The Charleston Gazette, West Virginia (whose dental problems rival those of its neighbor, Kentucky) passed a bill that will allow dental hygienists—whose services cost a fraction of those of a licensed dentist—to practice outside of a dentist's office and without a dentist being present. Legislators passed the bill—in spite of loud ADA objections—after journalist Eric Eyre wrote a series of articles detailing the state's abysmal dental care.

Bills like the one in West Virginia create new jobs while lowering medical costs. And there is perhaps a bigger benefit: putting smiles on the faces of millions of Americans who, thanks in part to the monopolistic behavior of the ADA, are literally too embarrassed to open their mouths."