For the sciences, you should have some sort of review book for each section, and then use the dat destroyer to help you focus on the material the DAT tests on. Look at old posts to confirm, but it seems agreed upon by most people that the destroyer is the book you want to use for the sciences.
For PAT, i thought crack the pat was a great program. It could be much harder than the DAT, but definitely good practice, and it gives clear answers (more or less) for the questions you get wrong so you can learn from your mistakes.
For verbal reasoning-find practice wherever you can. I used an examcrackers mcat book...just work on your speed and your strategy for tackling the questions
For the math section, i would find a pre-calc book and go over it. If you study from the Destroyer and topscore/achiever you'll learn the trig part ok, but you're gonna need something extra to learn the pre-calc they're asking on the DAT.
I don't know much about the kaplan class-look at old posts to get people's opinions but my feeling is that people tend to have mixed feelings towards it. As far as the kaplan book goes, I thought it did a really crummy job reviewing the sciences, but for the money it might be worth it just for the math and pat basics that it goes over.
Topscore and achiever material was really not what the dat was testing. Their science sections are especially off, so don't use them as your source. They're good though to help you become accustomed to taking the computerized test-and that's important.
The most important thing to remember is that it's well worth the investment now to spend the money buying all the study material you can. Dental school is mad expensive, so don't be afraid to spend lavishly for the DAT.
dat 8/18 22/22/19