173rd as MAJ Mower said may be more difficult. I don't know either if they have a Brigade Dentist. However, if you want to go to the 82nd...if there is a slot open (which there usually is one opening), and they have 4...it is much easier. People are leaving there pretty frequently. If you can't get it right now, just wait, you never know.
Additionally, don't forget about the group assignments with SF. They are fun slots as well.
One thing to keep in mind...if you plan on doing any specialty training (to include 63B), you can no longer go to these units once you graduate. So, if you want to do Hooah stuff, you have to do it beforehand. I have seen many Officers want to do these assignments after graduation, not knowing they are no longer a possibility.
Hope that helps.