This is the 4369th most frequent Portuguese word.
arrancado
"Arrancado" means "torn out" or "removed forcibly."
The word 'arrancado' in this sentence is used as a past participle to describe something that was forcibly detached, with 'dente' being the subject.
Elas viram um dente arrancado no chão.
They saw a pulled-out tooth on the floor.
Here, 'arrancado' functions similarly, indicating that the paper was forcibly removed.
O papel foi arrancado do caderno.
The paper was torn out of the notebook.
The word 'arrancado' metaphorically represents an interruption or abrupt disturbance of one's state, in this case, his dreams.