Here is my feeling on that one, has a working dentist.
If your coming to my clinic I will let you work as a dental assistant for a prescribed period of time. During that time I will train you to be a tolerable dental assistant. You will learn the basics of dentistry up close, both the good and the bad.
Please don't come to me and ask "shadow". I take "shadowing" to mean looking over my shoulder, getting in the way, asking stupid questions and pretending to my my friend so you can pad your dental school resume. I simply don't have time or the temperament for that kind of foolishness.
I am sure the thing that made me stand out as a prospective dentist was the year I spent working as a dental assistant in a clinic for the indigent in my college community. Where I worked with 3 dentists, 4 assistants and a hygienist and learned dentistry from the ground up.