The second time of root canal treatment is to continue the extraction of the remaining nerve of the tooth and to prepare the tooth for the subsequent treatment. In the case of a living pulp tooth, the second session of root canal treatment involves removing the nerve activity of the tooth in order to avoid pain during the continuation of the treatment at a later stage. In the case of a dead pulp tooth, the nerve is already necrotic and has lost its sensation, and the tooth is prone to fracture due to the lack of nutrient supply, and its resistance to external forces is reduced, so root canal preparation can be carried out directly. There is another important thing about the second follow-up of root canal treatment, the inflammation needs to be removed completely and the gum socket needs to be rinsed. The goal is to avoid spreading the inflammation and affecting other gum tissues. The second visit for root canal treatment is patient-specific and can be done in consultation with the treating doctor prior to treatment.