Fistula on gum some plaque buildup lack of cleaning for a year. has a crown over it no pain or swelling. sending me to endo but he doesn't have a 3d machine they want to do root canal how do i know it is needed. help thanks?

An Endodontist would be able to determine whether a procedure is needed with other radiographs and tests (often an ice test).

Multiple posts with the same question. If the tooth tests non-vital it needs root canal therapy.

You have a draining abscess that will never self heal, nor is it curable with pills alone. Technology is wonderful, sometimes. But your physical findings are irrefutable. And a 10 minute Google search is nowhere close to a 4 year 10,000 hour doctoral degree and years of experience. If you want to waste time and money corroborating the diagnosis, seek (and pay for) a second opinion.