A three-year-old child with tooth decay may need remineralization treatment, filling treatment, fossa sealing, root canal treatment or preformed crown restoration, etc. It is recommended to go to the hospital for specific treatment. 1. For bottle caries in the child’s front teeth, most of the superficial ones can be coated with fluoride to promote remineralization of the teeth. 2. If the cavity has been formed, it can be filled by removing the decay with dental drill or digging spoon, and then filled with glass ionomer or resin. 3. Children with cavities and deep grooves on the opposite side of the teeth can have their grooves closed to prevent caries. 4. Root canal treatment can be done if the decayed tooth has exposed pulp or if there is a shadow on the apical piece to avoid affecting the development of permanent tooth embryo. 5. Large defects can be restored with pre-formed crowns.