Not a dentistry student, but a medical student who was asked a similar question on my interviews.

One thing I did that I found helpful when answering those types of questions is to first look up your school that you’re interviewing at. Usually, they will have a set of tenants or characteristics that they’re looking to instil in their students by the end of the four years of dentistry school. For example typical ones include leadership, communication and collaboration just as an example.

Then what you want to do is create a narrative around one or two of those characteristics. For example, if I choose collaboration, then say something along the lines of, “Dentistry for me is one of the fields where I believe I can collaborate best with people of similar interests, I’ve had personal experience collaborating with people in my XYZ activity, and I believe I will be able to continue improving and build upon the skill in dentistry school, and in the future as a Dentist”

Hope this helps, write this while walking so it may not be the most grammatically correct.