In my present place we had a pit bull across the alley for three years that was the friendliest and most gentle dog anyone ever saw or hoped to see.
I don't think a breed makes one's set of teeth sharper than another's.
That has been my experience as well. To an animal, every pit bull I’ve encountered has been a big pussycat. Surprisingly friendly dogs. However, I think problem is that as a breed they have very powerful jaw muscles (right up there with rottweilers) and can produce tremendous bite pressure, so if you get a bad one you’ve got troubles. Usually the problem seems to come from people who have packs of them and train them to be vicious. Or they trust them unsupervised with an infant, which is a bad idea with any dog.