Basically, if you're applying and your DAT score is over 12months from the day of your interview, you need to take it again. People have reapplied with scores from the previous years and been told they are "old meat" and not taken as seriously. Dont give them a reason not to accept you. There are plenty of candidates with similiar GPAs and recent DAT scores, make sure you give them everything they want in every category.
Plus if you retake it, it helps to demostrated your point that you are serious about returning to school and serious about dent school.
Just my 2cents 🙂