Well as you've heard there are no rankings. Although thats not to say all the schools are the same. Many have REALLY high passing rates on the boards and get a lot of their students into post-doctorate specialty programs, and other don't. What it really comes down to is which type of school you want. Do you want one where people are cool and helpful? Do you want to be in a city? Where faculty will bend backwards to help you out? Guide you? etc? Even though the Ivy schools may not be as important if the field of dentistry, don't totally discount them, they are Ivy for a reason, the history is there, and they have good programs (just not for everyone). I chose to go to Penn because of everything: the faculty, the location, the clinics, the students, the specialization prospects, yes even the name. But I also picked Penn because it "Wowed" me. For those of you who don't understand, when you visit a school you your initial reaction should tell you something. The first thing I could think of when I walked through the doors at Penn, was "wow". No other school including the other big name schools did that for me.
In essence if you want the "top" school you'll have to find out what it means to be "top". Is it placement, prestige, location, name, cost, faculty reputation? There are plenty of schools which are great, and plenty which aren't worth crap, just .remember its all perspective