I know I already posted on this a while ago but to dive deeper into why I said it depends is because:
For example, you have schools like UF. Look at who they accepted into dental school... that's all I will say about that.
But my top choice, I asked a few dental students who go there and even one of the head admissions people (but not so blunt as this) about if I went to their undergrad school would it increase my chances and they all said "not one bit" -- but that was a particular school.
Those who say yes are saying yes because they know of schools that do, those who say no, say no because they know of schools that don't. I say it depends because it really does. Things factor in too, if you get to know the people in the dental school while going to the undergrad, of course that can help you... but alone, without knowing them and attending the undergrad, it depends on the school.