What makes the pit bull such a feared attacker is it's instinctual ability to grip and HOLD ON. This comes from it's history of baiting large animals such as the bear and the bull, and still to this day used as hog-catching dogs. The best way to defeat these types of animals, 10 times their weight and size, was to grip, and to hold on. It is already natural canine instinct to SHAKE their prey. This rips and tears the flesh that they grip, wounding their prey, to further submit to them in a fight. When their prey is still, they are less likely to do this. What lends to this style of fighting is the pit bulls unyielding DETERMINATION, also bred specifically into this breed. Put the two together, with some old wives tales of dogs who 'would just not let go' and you can see where this myth came to be. One story of an old 1800's pit bull breeder was that, in a bear-baiting competition, to further boast his dog's determination (called 'gameness' in this context,) was by chopping of the legs of his dog, one at a time. Each time afterwards the dog would struggle to resume fighting the bear. The dog died, but her puppies were in high demand.
And as far as the curvature of their canines go... well that one was just plain dumb, and I hope I proved it to them through the obvious comparison of Damon's teeth to Pippin's that they were exactly the same. Sorry folks, that one was just plain funny. It is not my parents fault how deeply the ignorance regarding pit bulls runs!