Do the ヴァンパイア have fangs when they bite または they just dont have them at all?

They don't have them at all. Stephenie explains about their fangs link.

"My ヴァンパイア do not have fangs. Their teeth are so sharp and strong that fangs are hardly necessary (they could bite through steel, if so inclined–a human neck is like butter, ha ha). The non-vegetarian ヴァンパイア don’t leave living victims (unless they are changing someone into a vampire); this isn’t the neat-and-tidy, two-small-holes-in-the-neck kind of vampire attack that あなた see in other vampire mythologies."

stephanie meyer's ヴァンパイア don't have fangs and are nothing like ヴァンパイア we used to, so everything あなた know about them (vampires from 前 本 and movies), all the myths,it doesn't involve stephanie's vampires.. so they don't have fangs but do have very sharp teeth with venom in it.. that's why edward doesn't french キッス bella, because she could easily cut herself..

twilight ヴァンパイア dont have fangs because their teeth are already sharp enough thats why when they bite someone, it makes a cresent mark, not two little holes

ヴァンパイア are REALLY different in stephenie Meyers books, we wouldn't expect any ヴァンパイア to be vegetarians would we, we thought ヴァンパイア would be all gothic, biting humans, having fangs ect. But in stephenies 本 everything is different, thay can be vegetarians, they are not all ゴシック and THEY DONT HAVE FANGS AT ALL!!. xx Also instead of making 2 little holes like a vampire with fangs would, it makes a creasent mark.

Idek

yes but not in Twilight

No, those 'Vampires' don't have fangs.
Coming to think of this, having read some of the 本 and seen all of the 映画 due to being a movie/book reviewer for a local paper... I can, as a mythology ファン as well as a die-hard horror story/movie fan, say I don't even see them as vampires.
Calling these creations ヴァンパイア is like saying a white dog with black spots is a cow または a panda-bear: They share similarities, yes, but they aren't what あなた call them. I prefer to see them as disco-globe mosquitos.

ヴァンパイア do not exist so the 質問 is invalid.