Vulval sealant, also known as point gap cleavage closure, is an effective caries prevention method that does not remove the tooth tissue on the occlusal surface, and coats a layer of adhesive resin on it to protect the tooth enamel from the erosion of bacteria and metabolic products and enhance the anti-caries ability of teeth, so as to prevent the occurrence of caries. The sealant forms a protective barrier to prevent bacteria and food residues from entering the sulcus, and at the same time, the existing bacteria in the sulcus gradually die because they are deprived of nutrition, thus preventing the occurrence of sulcus caries and stopping the development of early caries. Who needs to do the closure? When is it suitable for fossa closure? 1.In general, deep sulcus, especially those that can be stuck to the probe (including suspicious caries); 2.Patients with other teeth, especially those with caries on the opposite side of the same name or those with caries tendency should have sulcus closure; 3.Children’s teeth are suitable for sulcus closure when they reach the occlusal plane after eruption, usually within 4 years after eruption. 4.The best time for closure is: 3-4 years old for milk molar, 6-7 years old for the first permanent molar, 11-13 years old for the second permanent molar, and 9-13 years old for bicuspid. For children with disabilities with poor oral hygiene, although older or teeth erupted oral time is longer, can consider relaxing the age of fossa closure. Closure is simple and can be accomplished in a few steps by cleaning the teeth, acid etching, rinsing and drying, applying the sealant and curing. After curing, the material is tightly bonded to the wall of the sulcus and has a certain resistance to chewing pressure, which is not a hindrance to eating, and the material is non-toxic and harmless to humans after curing. However, it is important to emphasize that fossa closure needs to be performed by a professional and requires the necessary instruments and equipment. The sign of successful fossa closure is that the sealant can exist intact, suspicious wear and tear but can not fall off, so regular inspection is needed, if the material falls off need to be re-sealed. Indications: The sulcus is particularly deep, especially if it can be sown into the probe and the other teeth, especially the contralateral homonymous teeth, suffer from caries or have its tendency. Non-indications: there is no deep sulcus point gap on the tooth joint surface, good self-cleaning effect, those who suffer from more adjacent surface caries, the tooth erupts for more than 4 years without caries, the tooth has not yet erupted normally and is covered by the gum. The patient is uncooperative, the tooth which has done filling. Precautions after the surgery 1.After the surgery, if the closed teeth are found to have overbite or pain when eating within a few days, please follow up the consultation in time. 2.If you find that the sealing materials fall off or partially fall off after surgery, please follow up. 3.Repeat every 6 months or 12 months after surgery in order to find problems and deal with them in time.