The method of socket sealing refers to the use of special synthetic polymer material, purely from the morphological aspect, to fill and seal the cleaned, acid-etched and dried sulcus, and form a protective barrier on the surface of the sulcus to prevent the accumulation of food and plaque, isolate the caries-causing factors in the oral environment, so as to achieve the purpose of preventing sulcus caries. Generally speaking, the preventive effect is most satisfactory when the sockets of newly erupted posterior teeth (especially the newly erupted first permanent molars) are closed prophylactically. Of course, not all teeth at any age are suitable for the closure of sockets. Usually, we choose the deep grooves on the occlusal surface of the posterior teeth with the tendency of caries and the grooves with the initial or suspected caries for preventive closure. In terms of age selection, it is appropriate to seal the milk molars at the age of 3-4 years, the first permanent molars at the age of 6-7 years, and the bicuspids and second permanent molars at the age of 12-13 years. In other words, the front teeth, the adjacent surfaces of the back teeth, the teeth with obvious decay or already filled, and the teeth of adults are no longer suitable for the closure of the sockets. The process of closing the sockets does not need to destroy the normal tooth tissue and is painless. It is important to note that teeth that have been sealed should avoid biting on hard and sticky foods. Without proper brushing habits, any effective preventive measures will lose their preventive effect.