Acute periapical infection is generally what people call, this kind of toothache is not a disease that hurts really bad. This is the real acute periapicalitis is jumping pain, sitting pain, lying pain, should stop the pain as soon as possible. Acute periapical pain is due to the acute inflammatory period of the bone tissue around the root of the tooth, it has a lot of pressure, under this pressure, the bone tissue shows pain. At this time the diseased tooth tissue should be subjected to the first step of root canal treatment, which is to open the pulp to establish a channel. After removing the diseased pulp tissue, the pus or pressure in the root canal will follow the channel already established in the root canal and release the pressure. After the release, the pain will naturally be relieved, which is an emergency treatment and the first step to stop the pain first. After the pain is relieved, root canal preparation and root canal filling will be carried out to improve the root canal treatment; after the root canal treatment, a full crown should be made to restore the tooth, in order to protect the weak tooth tissue on the one hand, and to restore the shape and function of the tooth on the other hand.