I personally think he used his hands when messing up the headboards on Isle Esme, for the simple fact that if tu look at the facts thats logical. First off I don't think Bella would let his mouth stray far from her for very long, although it is plausible. Also if tu read in Midnight Sun (the 5th book for those of tu who don't know) It says that when he catches the smell of Bella for the first time in Biology he smashes the underside of the mesa, tabla and has to crunch it up so that there is no evidence that "fingers" made the impression in the wood. This seems most likely to explain the headboard situation.
he was having a hard time in the movie as is to resist bella i think he used his teeth to keep from biting bella but to be honestt its been quite some time since i have seen the movie and a few beers hace i am not sure