Dental schools look at both the science GPA and DAT scores. Without a sufficient GPA you are out of the game before you get started. A 3.5-6 science GPA is great, you just need to score around a 20/20 on the DAT and you should get into a dental school. If you score higher than 20 on DAT more doors will open up.
If you have a particular school in mind it is always best to contact them with your stats.
Hope this helps
Nancy