Whether to keep the two halves of a cracked posterior alveolar tooth or to extract all of it depends on the circumstances. If the tooth is cracked from the center to the root, it is best to remove the entire tooth. If the two halves of a cracked alveolar tooth are half big and half small, and not cracked to the root of the tooth, the small half of the tooth can be extracted. 1. If the two halves of the alveolar tooth are cracked to the root of the tooth, bacteria will develop from the crack to the deeper part of the tooth, causing long-term chronic inflammation of the tooth, and ultimately leading to the destruction and resorption of the alveolar bone, so it is best to remove the tooth in this case. 2. If the big half of the tooth is bigger and not cracked to the root, the small root can be extracted, and then root canal treatment can be carried out on the tooth, and then two weeks later, crown restoration can be carried out to restore the chewing function of the tooth. Whether to treat or extract the two halves of a cracked tooth in the back slot is timely to the hospital, under the advice of the doctor, to choose the most reasonable treatment method.