There have been many many research papers published on these issues. You can do a search on the Journal of Dental Education. All of them agreed that a humanistic environment was the most successful approach to dental education. The problem is at many schools the deans and other leaders in power still have the need to create a belittling, demeaning environment.
Our dean for 28 years, Dr. Dugoni has been preaching about this forever which is why we are lucky at our school to have a very respectful environment. There are other schools that have adopted this method of educating as well but not enough. As dentists we need to work together but how can these schools treat students like crap for 3 or 4 years and then expect them to forget everything upon graduation, come back to teach, donate, or collaborate with their collegues?
Students always enter school with so much excitement, dental schools should try and foster this enthusiasm instead of break it down. It would lead to much more compassionate graduates.