A three-year-old child with dark spots on the teeth needs to be treated according to the cause of the dark spots formation. The common causes are hyperpigmentation and dental caries. The black spots caused by pigmentation can be removed by daily brushing, rinsing and polishing, while the black spots caused by dental caries need to be repaired by filling treatment. 1.Pigmentation: If a three-year-old child consumes dark-colored food, such as chocolate, plum, or takes Chinese medicine soup, and does not clean the teeth sufficiently, the pigment will easily adhere to the tooth surface to form the tooth surface pigmentation and appear the performance of black spots on teeth. At this time, parents can remove the black spots by supervising children to brush and rinse their teeth after meals, and if necessary, dentistry to polish and clean the tooth surface; 2, caries: the black spots on the teeth of three-year-old children may also be caused by caries, which will destroy tooth enamel and manifest as brown or dark brown spots or plaques on the tooth surface. Fluoride application can prevent caries to some extent, but cannot remove the black spots on the surface of teeth. If you want to remove the black spots before the milk teeth fall out, you can restore the teeth to normal color by removing the decayed tissues and using filling materials for restoration. In daily life, parents need to pay attention to let children develop good oral habits and master the correct way to brush teeth.