I had a year of dental misery caused by teeth clenching, and had one root canal done by my own NHS dentist, and another done by a private root canal specialist endodontist. Both teeth were molars. The top tooth had really twisted roots, and my own dentist was happy to do it, but thought it might be quite tricky, and better done by the specialist - I was happy to be guided by her.
Both were done using a dental dam. The dental dam is a silicon sheet thing which basically isolates the tooth and stops it getting contaminated during the process. If either dentist hadn’t used one, I would have stopped the treatment!
The endodontist had a microscope, and mainly does root canals day to day, so was better equipped to deal with a complex tooth than a general dentist who does all sorts - although my own dentist is fantastic and I am 100% confident in her.
My own dentist did it in one appointment, the endodontist did two appointments (I think each was an hour and 45 minutes) then a final check about six weeks later, then my own dentist crowned the tooth.
I paid about £90 for my own dentist (Scotland) and the guts of £1000 for the endodontist.
If I had to do it again, I honestly wouldn’t see the benefit in seeing a general dentist privately - although I appreciate I am very lucky to have an excellent NHS dentist. I wouldn’t hesitate to see a specialist dentist privately if my own dentist recommended it though. She referred me to someone - which meant it all moved very quickly - and I was reassured that it was a person she trusted and rated.