Why are my fake teeth throbbing with pain?

Hi:Most likely there is an infection.  It’s best to have your dentist take an X-ray and evaluate the teeth right away.Best,Dr. Maddahi

You could have a cavity under a crown. There could be canals that weren’t found and so were not cleaned and filled. It’s possible there is a crack in one or both teeth. All of these are possibilities, the only way to know is to see a dentist for an exam and x-ray.