re: Is it legal for dental hygienists to open a teeth cleaning practice?

Yes, retired due to disability. Practiced for 20 years in a low fee, high quality practice. And I actually bragged about turning a $1.2 million practice into a $600K practice because quality dentistry was more important than money.
Ruzil has taken this thing so off track. He started out by painting hygiene as a money loser - I pointed out that it is a major earner in a well-run practice.
He tried to say that I must be money-hungry and run a shady practice with my wife skimming cash if hygiene turns a profit. I pointed out how contradictory that was to the type of practice that I actually ran.
He said an independent hygiene office couldn't run on low overhead and turn a substantial profit. I pointed out with facts that it can easily do that, and demonstrated how I thought things would operate in that scenario.
I pointed out that I hired hygienists whose diagnosis and treatment planning skills were better than some dentists I know, and he pointed out that he hires hygienists that can't tell a mental foramen from an abscess yet wonders why they aren't earning him money.
He has tried to turn that into me being an advocate for independent hygiene practices. In no way, shape, or form do I think it's a good idea. I just pointed out that if it happened, it would be profitable for hygienists.
You might have gained respect for him, but I lost all respect for him. And I actually held him in the highest regard prior to this thread.