There are two possibilities for a tooth to crack in the middle: the first one is a hidden crack, where the crack can be seen only from the jaw surface of the tooth, but it does not crack to the root of the tooth, or there is no obvious crack of the tooth. In this case, it is recommended that the patient go to the endodontics department and undergo root canal treatment under local anesthesia. After the root canal treatment is perfected, the tooth can still be preserved with a full crown protection. In the second case, the tooth is split in half by a longitudinal fracture from the middle to the root. In this case, the tooth has no value to be preserved and needs to be extracted under local anesthesia in the oral and maxillofacial surgery. Tooth splitting in the middle is due to poor eating habits, preferring to eat hard food or eating too fast, which can easily lead to longitudinal fracture of the tooth, it is recommended to chew slowly and not to eat too hard food.