After root canal treatment, the tooth may be sore and soft because of the irritation of filling material, incomplete root canal treatment, gum inflammation, etc. The reason should be clarified in time to do the treatment. 1. Stimulation of filling materials: During root canal treatment, the tooth needs to be filled, which may stimulate the gums, and the tooth may show soreness and pain after filling, which will be gradually recovered in about 2 to 3 days after filling. 2. Incomplete root canal treatment: Incomplete root canal treatment, there is pulp left in the gums, the bad pulp left to stimulate the tooth will show symptoms of tenderness and soreness. 3. Inflammation of the gums: During the root canal treatment, the gums are not cleaned properly, and there is bacterial infection, which causes the gums to be in the state of congestion, and it will cause inflammation to stimulate the dental nerves and enamel tissues, which will show the symptoms of soreness and pain. Patients are best to go to the hospital with the doctor to do physical examination, also need to do oral X-ray scanning examination, according to the results of the examination to diagnose the cause, to avoid blind judgment of the cause of the disease.