I think that within most of the health professions acts across the country, this is the limitation that's put on: a dental corporation can only be owned by a dentist. That is the reality, and it certainly narrows the market of who would want to buy that corporation at some point. Certainly, as you indicated, the dentist can't sell shares in it.
Borrowing is one way to access capital. The other way is, frankly, to save within the corporation to be able to access that capital on an ongoing basis.