As someone whose been on both sides of those interviews, the key is to be yourself. It's easier said than done with all that rides on those 20 or so minutes that you have face to face with representatives of the school. Just remember that if they invited you for an interview, then your stats are good enough. What they are looking for is 1) do you have the drive and determination to succeed both in school and in a career in dentistry, 2) can see themselves working with you for the next 4 years as instructors and for the rest of your career as a colleague.
IMO if you can engage with all members of the interviewing team and have a 'real' conversation with them, you are well on your way.
If you want more specific tips feel free to PM me.