My front tooth on my bridge moved when I bite something and now I have paid all under my bridge when I eat or drink. I have had the bridge fitted for 20 years at least what could it be. I am worried I may need a new bridge fitted.

You definitely need to see a dentist. The bridge could be cracked, the loose tooth could have an abscess or significant bone loss or the tooth with the crown that is loose may be badly decayed. You need to have an x-ray done for a proper diagnosis.