Why is my implant sensitive to hot and cold liquids all of a sudden?

Q. Hi! I had an implant placed in the back left side of my mouth in 1993. I\’ve never had a problem with it. Starting about three weeks ago it became sensitive to hot and cold liquids and cold food. Do you possibly know what is going on? It\’s the second molar from the back – large in comparison to the ones on each side of it so I don\’t think it\’s referred (?) pain. Thanks for any help you might be able to give.,