1, deciduous molars: that is, teeth that erupt over 2 years old, around 3 years old and around 2.5 years old. Because of the deep pit and fissure, it is easy to hide food residues, so pit and fissure sealing can be carried out. But at this time, it depends on the degree of cooperation of children. Although pit and fissure sealing is painless, it may be relatively difficult for children aged 2-3 to keep their mouth open all the time. Such a young child can consider applying fluoride, which is relatively simple;

2. First permanent molar: This tooth is very important. The caries rate of the first permanent molar is particularly high, usually 7-8 years old, that is, children in the second grade are more suitable. Of course, some children may grow up early, so they may do it early, and some children may grow up late, so they can do it later. This tooth can be sealed with pit and fissure. When making pit and fissure sealing, it is required that this tooth must be free of dental caries. If there are early symptoms of dental caries, pit and fissure sealing is not recommended. Because once closed, if it really goes bad, the doctor can't observe it;

3. 1 1- 12-year-old child's second permanent molar, that is, the one behind the six-year-old tooth. These four teeth can also be sealed if conditions permit.

Pit and fissure sealing is effective for teeth with deep pit and fissure and easy to hide food residue, which can play a better preventive role.