“How painful is a root canal without anesthesia?”

Extremely . . . Hell, it even hurts with anesthesia at times.

You should not get it done without anesthesia.

Good morning. Teeth that need root canals are of two types alive or dead. Performing root canal therapy on an alive tooth without anesthesia would be similar to an 80’s horror movie. Not advisable. On the other hand, it may be possible to perform root canal treatment on a dead tooth without using anesthesia in certain instances. With that being said, that having no blood supply (dead tooth) does not mean that all the nerve tissue is dead as well. I routinely recommend using anesthesia for all teeth requiring root canal treatment in my office. Good luck.