Whoa, I find them all pretty bad; it's way too fake looking. I honestly think most of them simply needed to whiten their teeth and be done with it.
Didn't Hilary get her teeth done because they started falling off? Something about her breaking her own teeth while singing, by hitting them against each other without realizing it. I think there was even an incident where she spit part of her teeth out on stage. Kinda sad.