I had a permanant crown put on a baby tooth that was 55 years old.  The baby tooth was decaying and dead.  Now I am having throbbing pain in the tooth area and when I click my crown with another tooth very sharp pains are in this area.  What could this be?
Hi. Can understand your concern. An per your complaint and explanation of symptoms the reason behind the pain is infection under the root tips of the tooth leading to formation of pus which causes pressure and pain. Any infection below the root tips of tooth causes pain on clenching the tooth with the opposing tooth and your symptoms are indicative of the same. I suppose that the root canal treatment was done before crown placement and any defect left during the treatment can lead to infection and inflammation after a few months or years. In case root canal was not done infection of the tooth due to ill-fitting crown or dissolution of cementing material can cause seepage of food debris and bacteria between the tooth and crown leading to nerve exposure and pain. I would suggest you to consult a dentist and get an x-ray done to get evaluated for the cause and get treated accordingly. For now, you can take a course of antibiotics like Amoxicillin+clavulanic acid three times daily and Ibuprofen 2 times daily for 5 days, but treatment is must for permanent relief. Hope your query is solved. If you find the answer helpful please write a positive review and click on find this answer helpful as a token of appreciation. Thanks and regards. Chat Doctor.