In rare cases, some teeth while having undergone a repeat of endodontic treatment continue to have symptoms. The main reason is the inability to remove the damaged or buried pulp from the complex morphology of the tooth's interior.

In these cases, the gums are lifted to reveal the root and clean the area with inflammation in the bone and the root that can not be purified in a conservative manner. The root is clogged by the microscope and special materials and the gums are restored to their original position by sutures.