1. Under the Sherman Antitrust Act, monopolies are illegal. There is, however, a "state action" exception; if one of the states, acting in its governmental capacity, creates a monopoly, the Sherman Act doesn't apply. That's why a state can pass a law forbidding non-lawyers from practicing law or non-dentists from practicing dentistry. Every state has laws like that.
2. In this case, North Carolina defines the "practice of dentistry" to include tooth-whitening, so spas and places like that can't do it.
3. If the North Carolina Legislature had written that provision into law, it might be stupid but it would clearly be exempt from the Sherman Antitrust Act because it would be the official action of the State.
4. But in this case, the State Legislature didn't write that restriction into a law; it instead passed a law saying that the practice of dentistry is regulated by the State Dentistry Board and that the State Dentistry Board is elected by the dentists in the state. That board enacted the tooth-whitening rule.
5. The Federal Trade Commission challenged the rule, saying that the state-action exception shouldn't apply because the rule was made by the dentists themselves, who have an economic interest in eliminating competition from non-dentists. The lower court (4th Circuit) agreed with the FTC.
6. The State of North Carolina appealed to SCOTUS, arguing that when the dentists made this rule, they were acting under authority delegated by the State, so the state action exception should apply.
Which is all a long way of saying that the specific issue before the Court is not teeth-whitening per se, but whether states can delegate their power to regulate professions to the people in that profession itself. So the conflict is between state authority and federal antitrust law.
imagine the confusion amongst all those folks whove bought Teeth Whitening Products...
Thank you.