Yep indeedy.
My sister went through the 1-year GPR program at Bellevue Hospital in NYC and it is exactly what Groundhog said.
She treated a lot of medically-compromised patients, many of whom were ASA class-III. Plus Bellevue provided dental care for inmates of the NYC Correctional System, so oftentimes she worked on prisoners in manacles while the marshal stood by with a shotgun.

And the prisoners often have all sorts of nasty diseases so it is challenging to plan and render treatment for them.
The upside? My sister also learned marketable skills like perio surgery and implant dentistry. Thanks to the skills she learned at the GPR, as a second-year dentist she's pulling in 35% at a group practice (amounts to about $150K gross).