Children with bad decayed empty teeth can be replaced with new teeth if the original teeth are milk teeth. However, if the decayed tooth is a permanent tooth, it cannot be replaced with a new one. Good dental protection and treatment can help. Normal children will start to replace their teeth when they reach about 6 years of age. If caries and cavities occur in the back teeth or other teeth during the milk teeth period, they will be replaced with healthy permanent teeth during the tooth replacement period. However, if caries and cavities occur in the permanent teeth after the tooth replacement is completed, the teeth cannot be replaced again and surgical treatment is needed to protect the teeth effectively. If caries occurs during the milk teeth period, children should have their teeth cleaned regularly in their daily life to avoid caries attacks on their permanent teeth, and generally there is no need for extraction of milk teeth. However, if caries or cavities occur in the permanent teeth, fillings should be performed as soon as possible to remove the necrotic tooth tissues to promote oral health. Children with decayed or hollow teeth should be examined promptly and consult their doctors for advice on the appropriate treatment options.