When the teeth of three-year-old children are decayed, the following treatment can be carried out: 1.When the decayed surface of the milk teeth is superficial, you can wipe away the food and soft scale attached on the surface of the teeth with alcohol, apply plaque stain, thoroughly remove the decayed material, apply sodium fluoride, stannous fluoride and other solutions to promote enamel remineralization and avoid the expansion of the decayed damage. 2.When the decayed anterior teeth of the milk teeth affect the anatomical form, choose a plastic crown of suitable size after removing the decayed material and inject composite resin After the resin is hardened, remove the excess material to restore the shape of the crown. 3.When the posterior teeth of the milk teeth are decayed in a large area, place prepared calcium hydroxide at the bottom of the cavity, use silver amalgam and other filling, and make metal preformed crown restoration if necessary.