A five-year-old child with painful tooth decay first needs to be properly reassured and treated aggressively. In the case of a painful cavity in a back molar, the caries has reached the pulp, and the tooth should be drilled to open the pulp and drain it so as to control the acute inflammation. After the acute inflammation subsides, root canal treatment is performed. Back molars are usually not replaced until around 11-12 years of age. If there is swelling in the gums, i.e., the decay has developed into periapical periodontitis, then the tooth needs to be drilled open to drain the root canal so as to control the acute inflammation, and after the acute inflammation subsides, root canal treatment with radiographs is also required. In the case of front incisors, when the tooth decay causes pain and inflammation of the root tip at the age of about five years, after the inflammation subsides, radiographs will be taken to look at the inflammation of the root tip and the growth and development of the permanent teeth. If you are in the replacement period, i.e., you are about to replace your teeth, and the root tip lesion is serious, and your baby teeth are loose, you can consider extracting them after the anti-inflammatory process. Therefore, for the pain caused by tooth decay around the age of five, it is necessary to control the acute inflammation first, and after the acute inflammation is controlled, according to the developmental status of the teeth, the replacement period, and the apical lesion, then take appropriate treatment measures.