First off, I think it's important to remember that dental schools aren't going to be looking at your business GPA at all. They're basically going to just be looking at your overall GPA and your science GPA.
To answer your question about geoscience, it most likely will count towards your science GPA. If I were you, I would aim to get straight A's in the rest of my pre-reqs for dental school, do VERY well on your DAT, and beef up the qualitative aspects of your application. After completing your pre-reqs, if your science GPA is not at least a 3.0, I would consider a post-bacc/master's.