agree with ihd,
I applied to ~ 20, Why not? It is only a couple hundred bucks more. I am so glad I did too because you never know what schools will lose your app, deny you or just randomly ignore you when you are qualified to attend any dental school. IHD said it best. Applying is a crapshoot, play the odds. You can withdraw afterward if needed, but adding them later is not the way to go.
I attended only the interviews I wanted too, and got accepted to most of those schools. It is hard to be picky when you only have a few offers. Besides, I took the DAT after submitting AADSAS app, so I had no idea what my actual score would be. I was playing it safe, and it worked for me.
The other consideration is if you have a state school. Most have smaller number of apps for residents with more seats for them, so your chances are, in most cases, greater.
If you are from Utah, I would apply to at least 20 because of the wicked competition. You can always tell schools that you have your list narrowed down to three or four schools (that school being number 1) when the question comes up. 😀