It’s not health, but favoring some businesses over others (and over consumers) that’s the concern of Connecticut’s regulators:
Here’s the description of the Institute for Justice’s video:
Teeth-whitening services are popular and increasingly available at spas, salons and shopping malls. This has been a boon for consumers because these businesses offer whitening services at a much lower cost than dentists do, often charging less than 25 percent of what a dentist would charge for similar results.
There is one group that is not smiling about these new, low-cost teeth-whitening services: the Connecticut Dental Commission. In June, the Commission ruled it is a crime punishable by up to five years in jail or $25,000 in civil penalties for anyone but a licensed dentist to offer teeth-whitening services, even if the customers apply the product to their own teeth.
Teeth-whitening products are regulated by the FDA as cosmetics, which mean anyone—even a child—can purchase them and apply them to his or her own teeth without a prescription and without supervision or instruction.
The Dental Commission’s ruling has nothing to do with public health or safety and everything to do with protecting licensed dentists from honest competition.