Answer:
What dentists battle on a daily basis
He died for people's entertainment.
What is it that no man ever saw, which never was, but always will be?
No matter how little or how much you use me, you change me every month. What am I?
What has no hands but might knock on your door, and if it does you better open up?
As round as an apple. As deep as a cup. All the king's horses can't pull it up.