I don't think they have a real cutoff, though an 18 on the AA seems like the minimum they are letting in nowadays. There are plenty of students with low PATs gtting in but usually have a stronger GPA or AA to back that up.
I am in a 3/4 BS/DDS with buffalo and they require us to score a 20AA/18PAT to get in. The 18PAT might be high for some folks and easy for others. This is what concerns me the most, not getting that 20 on the AA.