Holy sh**.
A patient, female, 25 years old, needed canal refilling in a premolar. The canal was slightly curved naturally, which the doctor was notified about in advance. During treatment, the patient felt (even with anaesthesia) that a wards carver (my guess) was going too straight - the doctor told her not to worry and PRESSED the instrument instead of slightly turning it. And made an additional canal in the mandible. The patient learned about it postfactum.
5 years later, the patient went to another dentist. She needed a canal filling in a tooth adjacent to that tooth with the new hole. The doctor was notified IN ADVANCE that there was an artificial canal made by the first doctor and that it would be good not to accidentally fill it. "Sure," said the doctor, "although it sounds like you're exaggerating." Maybe the doctor thought that it was impossible to be that stupid and crooked-handed. The patient got a sectional matrix placed and then asked to do a 3D photo just to make sure everything was placed correctly.
The point is that the sectional matrix, or some metal part of it, hid in the photo the very place where that unnecessary channel was made. The second doctor decided not to remove the matrix for another photo, she thought everything was okay.
After the filling, the second photo was made - and it showed a perfectly filled canal in the problematic tooth... and a giant cube of filling in the mandible.
The moral: Listen to your patient. Even if they're exaggerating. You are welcomed as a doctor to pretend that everything is okay, but you must check it trice.













