Remember that this is Frank Miller inspired so the teeth are because, when Batman caught the Joker, after he and Harley Quinn killed Robin, he knocked all his teeth out in a brutal beat down so this is the aftermath. This is by far the sickest incarnation of The Joker for live action purposes and I fukcing love it!!!!! Makes perfect sense when you realize that Bastman's new look is 100% Frank Miller.
Frank Miller's style isn't always a hit with movies (see Daredevil) and is sure to alienate pu$$y bitches like chemmie, but as a fan, I'm super excited that DC is pretty much being the anti-Marvel and going as Dark as they possibly can with their movies. 2016 will be awesome!!!