You will spend the first two years as a medical student (Take almost all of your classes with medical students). They have a "hybrid" PBL system. So you still get lectures, but also problem based learning. Harvard's name will help if you want to specialize, go into academia, or public health, but doesn't offer any particular advantage for being a general dentist.
I didn't go there, so that is just my impression from my interview and friends that went there.