Is the Bronx in New York City dangerous?

Yes but the whole nyc is getting more and more dangerous.

ALL of nyc is dangerous. 90% chance of getting stabbed

It's more dangerous than the other boroughs. 

If you walk across the street without checking first, that's dangerous so any city in the world is dangerous if you don't use common sense.

Yes it is especially the South Bronx

Any part of a city can be dangerous.

Would I be missing four of my teeth from getting kicked in the mouth over and over if it were not?

Some part of it.