Generally speaking, deep sulcus, especially those that can be stuck to the probe (including suspicious caries); 2, the patient’s other teeth, especially those with caries on the opposite side of the same name or those who have the tendency to have caries should be closed; 3, children’s teeth erupting to reach the occlusal plane is suitable for sulcus closure, generally within 4 years of eruption. Qiu Haiming, Department of Stomatology, Liaocheng People’s Hospital 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 longer, can consider relaxing the age of fossa closure. — Vulval 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, after curing, the material is non-toxic and harmless to humans. 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 re-seal. 1.Indications; the sulcus is particularly deep, especially it can be sown into the probe, other teeth, especially the opposite side of the same name tooth suffering from caries, or those who have its tendency. 2.Non-indications; there is no deep sulcus point gap on the tooth joint surface, the self-cleaning effect is good, 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 been done filling. Precautions after the surgery 1.After the surgery, if you find that the closed teeth have overbite or pain when eating, please follow up in time. 2.If you find that the sealing materials fall off or partially fall off after surgery, please follow up. 3.Recheck every 6 months or 12 months after surgery in order to find out the problem and deal with it in time.