Personally, I wouldn't have any questions ready because they might not fit with the schools program or may have already been addressed in the introduction. As you are lectured on their curriculum, you will find many questions to ask. Be willing to ask the students questions during lunch. They are usually honest and willing to answer questions that you might feel uncomfortable asking a faculty member. Here are some questions you to think of but you'll find some of your own the day of the interview.
1)Do students find time to get involved in extracurricular activities like research or clubs?
2)How many of your students pursue residency after graduation
3)Most popular specialty?
4)Do u have an online library?
5)Do you have a program that networks the dental students with med/pharmacy/law students
6)Do you offer any additional classes like forensic dentistry?
7)It it is a pass/fail system, you may want to ask if students work together considering they are not competing for grades.