I have never had a root canal. I do agree nerve pain can arrive due to untreated infection/inflamation. But, when nerve pain arrives due to a foreign object being forced into the IAN or LN.. It's not about the condition of any other teeth. I live with LN damage. It feels like 4 teeth should have been extracted along time ago but the teeth are ok. My tongue is 50 times worse than the teeth pain! Dental malpractice cases do exist and expert lawyers are available. Dental boards are available for public complaints. I do agree that it is not always the fault of the dentist when complications occur and that's what consent forms are signed for.