Dental fossa sealing is one of the preventive measures against dental caries, which is a method of applying a fossa sealer to the fossa and part of the tooth surface. Fissure sealing is a method of preventing dental caries by applying glass ionomer or light-curing synthetic polymer resins with good adhesive force and promoting dentin development to the fissure and part of the tooth surface. Dental fossa sealing is one of the better measures to prevent dental caries, the fossa of the milk molar, young permanent molar and other caries-prone parts of the fossa has a sealing effect, usually able to prevent 60% to 90% of the rate of caries. Generally in the new eruption of teeth within four years can do dental fossa sealing, do dental fossa sealing is not a substitute for brushing, do fossa sealing also need to brush your teeth well to prevent dental caries.