I have had bad joint pain for at least 6 years and recently took amoxicillin anitbiotic for an infected tooth. my joint pain completely vanished.

Hard to say: It is hard to say what happen with the information given. Can't tell you if this relief will be long lasting or just short term. Keep an eye on things and if the pain returns see your docto or dentist again for an examination of the problem joint. Good luck in the future.

Antibiotic: First, antibiotics do not cure dental infections, just reduce the severity of the infection, so see your Dentist for appropriate supportive Dental treatment. Second, your change in knee symptoms could signify infection. Please see an Orthopedic Surgeon or Rheumatologist for evaluation.

Sudden loss of pain: I didn't see a question, but here's an answer anyway: The two factors you mentioned- joint pain & taking an antibiotic resulting in the loss of pain after six years would more than likely be a coincidence (even though you might doubt this) than a direct cause-effect. It's impossible to know the cause of your pain without seeing you personally. Hope your pain remains gone. See dentist if it recurs