(1) Soreness - Most patients experience a little soreness after the appointment. This may be due to the injection, the necessity of keeping the mouth open for a long time, or the treatment. Your temporary filling will be hard enough to bite on within approximately a half-hour, but avoid biting or chewing on the treated tooth if it hurts. (2) Pain - Over-the-counter pain relievers usually relieve the discomfort. Should pain last more than a few days, or if severe pain or swelling occur, call your dentist. Remember, if your tooth hurt before you came in for treatment, it may take a while to heal. (3) Permanent Filling - When your root canal treatment is complete, a temporary filling is placed. The tooth needs to be permanently restored to prevent contamination or fracture, so you will need to return for a permanent restoration. It is important to return promptly because the temporary filling can loosen and leak, possibly causing the root canal treatment to fail, which would necessitate re-treatment.