Yep, the Dentistry course in NSW is post graduate; sucks cos if you really wanna do dentistry, you will need to travel interstate to either Adelaide Uni, Melbourne Uni, Queensland Uni, and even Western Australia Uni has it. I swear, only uni's in NSW is tight enough to make it a damn post grad course. Going interstate was one of the reasons that disencouraged me from doing Dentistry.
Anyways, the UAI is not the only requirement for Dentistry. You gotta do the UMAT and go through an interview process (except for Melbourne Uni I think). You gotta be an all-rounder in both the UAI and UMAT to be selected;
for Adelaide Uni, you need a UAI (TER - same thing) of 90;
http://www.adelaide.edu.au/programs/ug/prog/health/
for Melbourne Uni, you need 96
http://coursesearch.unimelb.edu.au/
for Queensland Uni you need a rank of 99 (dunno what the UAI equivalent is)
http://www.uq.edu.au/study/program.html?acad_prog=2257
for Western Australia Uni, you need a TER of 96
http://admissions.uwa.edu.au/undergrad/courses/dentistry
So yeah, in the end it just depends whether you're determined enough to wanna go interstate. I've heard its really competitive as well, but it's worth a try