It's a myth that NYU fails lots of its students.
The truth is there are always students who fail the first year at every dental and medical school, or decide its not for them. There aren't more people failing at NYU than other schools.
If you fail a class, they give you plenty of second chances. A private school has no incentive to kick out students. They want you to succeed and graduate.
Also for sim lab - on tour there I believe they said that they split the class into groups of 60.