There is absolutely no excuse for being under-prepared for the the basic questions that you know will be on there "why do you want to become a dentist? Why this school? What do you do with your spare time? etc." I gathered as many likely dental interview questions as I could and wrote out responses to each question. Writing helps condense rambling thoughts into a concise answer...it works for me anyway. As it turned out, 90% of the questions I had prepared for weren't even asked, but I felt much more confident during the interview knowing that I was prepared. Spend a little time on it and you'll do fine. Good luck!