It all depends on what kind of questions your interviewer feels like asking you on the day of your interview. They could ask you anything, ive had interviews that ranged from laid back simple converstations to intense questions about my grades and undergrad.
I do know of and have heard of interviewers asking predents about current events with regards to dentistry, medicine, health care issues and major world events.
Your best bet is to do some research on the school and keep up with any major topics or current events occuring in dentistry, medicine, or health care.
Also check the interview feedback questions to see which kinds of questions predents are being asked.