At 85k a year salary with a rent of $550 a month, what exactly stopped you from saving a lot? The buffer of money saved helps a lot in making it feel like you're okay financially after you stop working.
When I went from a full time salaried job to full time student, it wasn't really a hardship at all. I simply took out the student loans I'd need to supplement what I'd saved to pay for my cost of living and tuition. Because student loan payback is deferred until after you graduate (and sometimes several months after that even), there wasn't really a feeling of being poor. Of course, I took enough out so that I could still go out occasionally, and eat pretty much the same way I did while I was working...I didn't think living ultra-conservatively, penny-pinching, was worth the lack of stress relief or added stress from too drastic of a change in life style.
Two things I hated: giving up my car and only using public transit, and using laundromats. Course that was hard to avoid moving to NYC (apartments with washer/dryers were scarce, and owning a car was a huge expense for many reasons, and not necessary).
I'd think as long as your salary post-graduation is enough to support all your basic cost-of-living needs and bills, and you weren't living some kind of extravagant life before school, there shouldn't be much difficulty in the transition. Unfortunately I don't know how different it might be post-dental school debt, as it's far far more money than I ever owed. Somehow whenever I think about the high end of dental school student loan debt, it doesn't seem proportionate with what a new general dentist will make. 🙁