It is normal to experience mild pain with a gradual decrease in symptoms within one to two weeks after root canal filling; otherwise, it is recommended to consult a doctor for root canal retreatment. 1. Within one to two weeks after root canal filling treatment, slight swelling and pain or occlusal discomfort may occur in some cases, which is mainly caused by the stimulation of the filling material; however, the symptoms are mild and will be gradually reduced, which is a normal reaction after root canal filling and generally does not require special treatment. 2. Long-term occlusal pain, spontaneous pain or irritation pain after root canal filling, and the symptoms are gradually aggravated; then there may be overfilling of the root canal, root canal leakage and other symptoms, and it is necessary to consult a doctor for re-endodontic treatment, i.e., removing all of the filling materials and re-conducting anti-inflammatory and pain-relieving treatments. In serious cases, it is recommended to actively seek medical advice and follow the doctor’s instructions for examination and treatment.