Most schools use CDA which are pre-determined questions so they won't likely ask you about previous professional education. However, it's possible at schools that use MMI like McGill. Also, Western usually asks some non-CDA questions that supposedly aren't scored but even those seem to be randomly chosen from a list of pre-determined questions lol.
Can't really speak to schools outside Ontario and Quebec.
Also, pharmacy to dentistry isn't uncommon, I've seen it happen a lot. Dentistry to medicine also happens (more rare), but it happens and so does medicine to dentistry.