School-age children due to the large amount of sports, self-protection awareness is poor, easy to fall in the process of strenuous exercise or chasing each other and lead to dental trauma, especially in the developmental period of the front teeth, due to its periodontal and alveolar bone tissue laxity, the root of the tooth has not been fully formed, the root of the tooth is shorter, so it is easy to appear the whole tooth loss. What should children do if they have lost their teeth due to trauma? First of all, we should not discard the lost teeth at random. Children are in a period of vigorous growth and development, the tissue repair and regeneration ability is very strong, lost teeth under certain conditions as long as timely and correct treatment of dental reimplantation (re-introduced into the original alveolar fossa), it is still possible to continue to exercise their functions. Secondly, after dental trauma to the ground, the surface of the tooth is often stained with dirt, which should be properly cleaned. Dirt can be rinsed with saline or tap water, but it is important to avoid scrubbing or scratching the surface of the root of the tooth with force, as this can damage the periodontal tissues living on the surface of the root of the tooth. For the same reason, in order to protect the periodontal tissues living on the surface of the root, when picking up the tooth or performing cleaning, the crown portion of the tooth should be held in hand and excessive contact with the root should be avoided as much as possible. In addition, it is important to have the correct method of preserving the lost tooth. When the tooth is found, many parents hold it directly in their hands or wrap it in a piece of paper or a handkerchief and send it to the hospital, which is not an appropriate measure. After the tooth is completely dislodged from the alveolar socket, it is exposed to the air for a long time, and the dry environment will cause necrosis of the periodontal membrane cells on the root surface of the tooth, which will affect the healing of the periodontal tissues after reimplantation. Therefore, it is important to avoid placing the tooth in a dry environment, and it is best to place it in fresh milk or saline for preservation. If the child is older and not prone to swallowing, etc., the dislodged tooth can also be placed under the tongue. After a tooth is lost due to an injury, it should immediately go to a regular oral health care institution for standardized and systematic dental re-implantation, fixation and other treatment measures. Because the length of time from tooth loss to implantation back into the original alveolar socket is the key to the success of reimplantation, the shorter the time, the higher the success rate. Therefore, we should try to minimize the time of dislodged teeth.