Now commonly used on the market are mostly arsenic-free inactivators. Ingredients are mainly paraformaldehyde, relatively safe and effective, pulp inactivator include: 1, arsenic trioxide, can make the capillary extremely congested, cell destruction after blood circulation disorders, tissue necrosis, but also be able to make the pulp within the nerve fiber expansion, inactivation; 2, metal arsenic in contact with the dental pulp is transformed into arsenous acid, mainly to make the pulp congested, embolism and inactivation, the role of slow; 3, paraformaldehyde can Causes damage to the capillary endothelial cells in the pulp, nerve paralysis after the pulp gradually necrosis, the role of coagulation protein, so that the pulp to maintain aseptic state, the role of slow and safe; 4, Toad Crisp Compound, within a short period of time can make the nerve paralysis to achieve painless, is a safer pulp inactivation agent.