With any root canal or extraction it's best to have an Endodontist or oral surgeon perform the procedure. I had a root canal and crown about 10-12 years ago, the same root canal developed an infection 5 years later and had it fixed & cleaned out, via going into the area form the side not top down where the crown was fixed, fast forward to this past October 2022 I had to get the crowned molar removed. It's best to keep the tooth if possible, that's why we opted for the 2nd repair. But, you can only repair so many times. In hindsight would probably go with an implant to avoid the 3x cost of fixing and replacing the same molar. It will be around 15k USD for 1 molar after this last permanent implant. That's with insurance.
Even if the root canal looks impeccably clean with X-rays it can get reinfected, it makes sense now. It's a compromised area.
None of my procedures were painful, shots not NO2. Your teeth can shift that's why you need something permanent in place.
1) root canal was not repairable, extracted the whole tooth, $1200.00 USD
2) let heal for 3 months, the new bone graft had to grow and take where the former back molar was located
3) bone graft was perfect, cut area, screwed in metal post, $1800.00 USD
4) end of Jan 2023, all should be good to go, will receive hardware that is fixed to the post where the implant will be fixed.
I used a American Board of Oral and Maxillofacial Surgery dentist/physician located in Southern California, expensive but it's your mouth and you don't want any issues and he is one of the best.
5) Will be going to Thailand in April 2023 for the implant and looking for references.
Do your research with any procedure and ask questions once you think you have a possible dentist/Dr/surgeon, etc, you are the one that has to live with it so make sure you leave nothing to chance. https://www.fda.gov/medical-devices/dental-devices/dental-implants-what-you-should-know