When a child has a bad sixth tooth, it is first recommended to take a radiograph to check the depth of decay. If it is superficial, medium or deep caries, but there is no pulp leakage, this case can be filled directly with light-curing composite resin material. If the deep caries is closer to the nerve, it can be cushioned, using 3M glass ion or choose to use calcium hydroxide preparation for indirect pulp capping and then composite resin filling, and the tooth can be used normally. If the area of tooth decay is large, inlay restoration can be done, and it is generally recommended to carry out restorative treatment after adult. If the bad nerve of the sixth age tooth has been exposed, this situation needs to kill the nerve treatment, but need to choose the specific treatment plan according to the development of the root of the tooth. If the root is not fully developed, apical induction molding can be used. If the roots are already developed, root canal treatment can be done and wait for porcelain braces to be restored in adulthood in order to ensure that the tooth is fracture resistant and avoid tooth splitting.