Dental fistula pus has been eliminated nerve has been broken that inflammation has been eliminated, but the tooth crown side needs to be filled, tightly closed, so as to avoid bacterial infiltration, causing periapical inflammation recurrence. 1. Dental fistula pus has been eliminated nerve has been broken indicates that the necrotic pulp nerve tissue removal, inflammation has been eliminated. However, in order to avoid bacterial infiltration and recurrence of periapical inflammation, the root canal and the crown side of the tooth need to be filled and sealed tightly. 2. With regard to the closure of the crown of the tooth, a filling or crown restoration should be performed on the affected tooth as soon as possible after the root canal is filled in order to maintain the integrity of the tight closure of the root canal system. If the crown side is not closed for a long time, it is usually necessary to carry out root canal treatment again. It is recommended to consult a medical professional.