Newly placed crown is loose - was not all the way sealed and seated.

I had a crown placed and when feeling returned, I could tell it was not all the way seated. It's loose and clicks when moved with the tongue. It is also tender: movement seems to be aggravating the remaining tooth pulp. I returned to the dentist immediately- he acknowledged that it was slightly loose but he couldn't remove it because of the cement. He also checked my bite - it was ok. Is this caused because of a bubble in the cement? Can it be removed and re-glued? Will it work its way looser?