A polymer resin material is used to seal deep grooves on the surface of children’s teeth by light curing. It is equivalent to putting a protective coat and armor on children’s teeth to prevent food from entering the deep sulcus, which will lead to uncleaning, fermentation and acid production and finally tooth decay. It is also an internationally recognized method to prevent dental caries in children. For children with milk teeth, i.e. around 3 years old, generally all milk teeth have erupted, at this time, if the sulcus of milk teeth is deep, the sulcus can be closed. For permanent teeth, the sixth age teeth are the teeth growing out from behind the last milk molar around 6-7 years old, if the sulcus is deeper, effective sulcus closure can also be performed around 7 years old. After the eruption of this tooth, sulcus closure can be performed according to the situation to effectively ensure that the surface sulcus of the milk teeth is smooth, minimize food accumulation and protect dental health.