Tennessee recently became the most recent of a handful of states to crackdown on the teeth-whitening business.
Teeth-whitening franchises have run afoul of several state dental boards and, in January, the Tennessee Board of Dentistry declared that the kiosk-whiteners are practicing dentistry without a license.
Joyce Osborn, president of the trade group Council for Cosmetic Teeth Whitening, went before the board to unsuccessfully argue that teeth-whitening is safe.
"In doing lots of research, we have made sure we are not practicing dentistry, that we are providing a self-administered application for whitening the teeth that is safe, affordable and effective," Osborn tells NPR's Robert Siegel.
Dentist John Douglass, who sits on the Tennessee Board of Dentistry, disagrees.
"The main problem is the perception that they are doing a dental procedure," he tells Siegel. "We on the board feel that it is our responsibility to regulate any procedure that is deemed to be practicing dentistry and this is to protect the health, safety and well-being of the people of Tennessee."