It was very relaxed and conversational! It is three interviewers and 12 minutes each. Honestly, relax, be honest, and be yourself and you should be golden! Essentially most of the conversations consisted of things on my application so if you can back up all of what you did the past few years, you should be fine. Also, be sure to explain any weaknesses in your app (depends on your interviewer), because one of my interviewers asked me why I got Bs in two classes during my junior year right before I applied after maintaining a 4.0 throughout my freshman and sophomore years. But yeah, there's not really much besides researching the school (as with every other interview), being able to explain why you want to do dentistry, knowing your application well, and simply just being yourself!