When GPA is low, like everyone said, make sure to keep your image strong so do well on the DAT, work, accrue extra curriculars and shadowing etc.
The alternate route I have seen a lot of people take (both in dental and medicine) is post-bacc studies. If you have the interest, get in somewhere and you'll increase GPA and show your propensity for higher education. If you pick the right programs, you probably will get a decent enough stipend while you earn an extra degree etc. If you don't have serious interest in research though, probably not the best idea.