One of the pre-health advisors at my schools suggested this. Dont recite your personal statement or your whole application. the whole life span between your birth and your college arrival should not take more than 30 seconds. But within that if there was a moment which triggered your interest in dentistry then elaborarate a little on that. Next you get into college years, this is what they want to know. Tell them why you chose your major, if you did research, extracurricular activities, work, any positions held. You dont have the tell them all of them, pick the ones that you consider to be your sell [pints. Make sure you mention all your sell points in the answer. The total answer should nt be longer than 2 minutes. At the end, you dont want to trail it off, you end by saying, "If there's anything that you'd like for me to go into detail, I'd be happy to elaborate."
The point of this question is to set the stage for further questions, you want to mention thigsn that youw ant them to ask about you. If you did research mention that and they will ask you more questions about it later. If there is a hobby that you enjoy, mention that. Try to relate things to the profession, it shows your interest and committement. Try to set yourself apart in a good way, mention things about yourself that you feel are unique, I mean eveybody volunteers at a hospital. Tell htem a specific experience you had during this or some other dental experience or life experienmce that sets you apart and which encouraged you towards the healthcare field.
This is my suggestion, I hope it helps.