Fine endodontist and fine man.
I had a serious problem with a tooth that was root-canaled in ~1995, in San Diego. It was a rough job as my canals were quite calcified and the Doc could only get three of the four roots done. He told me such, but what he neglected to tell me was that, in trying, he penetrated the tooth, exposing the area underneath it to decay.
~13 years later it began to act up from time to time. By ~2011 it was hurting all the time, so my general dentist referred me to Scott Johnson at Endodontic Specialists.
Dr. Johnson worked on me for 2 hours to get down the "lost" root. He then had me return 3 weeks later, to work another 2 hours, no extra charge. When finished, he warned me that saving the tooth was iffy due to the 1995 work. He was correct.
6 months later I saw him for a checkup where he told me the tooth needed extraction. Remarkably, he said he was going to REFUND half of the fee I had paid him. AND HE DID, which I still find astounding as I've had numerous medical procedures that failed, but was never offered even a nickel back. That kind of ethics is all too rare!
Given how hard he tried, and his ethical values I recommend this, Doc wholeheartedly. No one could have saved that tooth!