The field of dentistry, or medical research in the field of dentistry, is an area that will generally require a PhD, or a dentistry degree plus a few years of post-grad professional experience.
PhD students in this area usually get into tutorial or undergrad lab class supervision, that kind of thing. But that can be an interesting experience with which to build your teaching expertise up to the kind of full-blown undergrad or postgrad lectures you may be required to do after you earn your PhD.