Does all Dental school required an interview before getting accepted in?

That's not necessarily how interviews work. They're not judging you on your attractiveness.

One simple fact of an interview - they're trying to see whether the person who applied is indeed for real. My former graduate school used to accept people on GRE and grades alone. They ended up getting a bunch of people whose English was beyond unacceptable, despite having higher verbal GREs than I did. A quick phone interview was enough to verify things.

Yup :) its just like a job interview.

Frankly, if you're that worried about your appeance keeping you out of college it'll also keep you out of the job market for the same reason(s).