A 13-year-old child with a slight crack in an injured tooth will not grow back on its own. Depending on the situation, you need to consider resin restoration and crown restoration after root canal treatment. 1. Resin restoration: when a tooth is injured and a crack is found, it is usually an occult fracture. If the part of the occult fracture reaches the enamel or dentin layer and does not involve the pulp, dentin sensitivity may occur, and a resin filling can be used to restore the fracture by grinding away part of the tooth tissue along the cracked part with a special instrument. 2. Root canal treatment and crown restoration: If the crack has reached the pulp cavity after examination and caused pulp inflammation, root canal treatment is needed to remove the pulp and then crown restoration of the tooth is carried out. It is recommended to go to the dental hospital in time to deal with the cracks after the tooth is injured, so as to avoid the cracks from deepening and further damaging the health of the tooth.