What is the surgical management on abscess like symptoms on six month old root canal? This tooth was previously root canaled.  I thought it was not done before so the dentist drilled this tooth and found that a root canal had already been done before so he resealed it and put a new crown (old one was chipped) on.
Now, I am positive I have an infection. The superior gum margin is sore and X-ray is non-contributative because the
 infection is small. Three grams/day Amoxycillin for 10 days did not  work. Nor did  Augmentin work.   Now I'm trying Ciprofloxacine.  If this antibiotic doesn't work? What other antibiotic would be next in line to use. What surgical intervention can be done in this delicate case, as a last resort; aside of extracting the tooth. I truly need your advise. The dentist thinks I'm joking because he can't see anything on the x-ray. Help!

Summarized question: What is the surgical management on abscess like symptoms on six month old root canal?