Commonly used methods of fossa closure 1, self-etching bonded fossa closure 2, full acid etching bonded fossa closure 3, enamel forming closure 4, enamel forming + full acid etching bonding closure 5, conventional method Self-etching method sounds involved with resin restoration, in fact, the fossa sealant is resin. With the further development of self-etching bonding technology, because of its simple and fast operation, biocompatibility is also very good, in the resin and restoration treatment is widely used. However, the experimental comparison of the effect of this method on the sulcus closure is not optimistic: the complete retention of the self-etching is significantly lower than that of the phosphoric acid type, and the reason for such a result we think may be that the self-etching uses a weak acid to treat the enamel surface and does not rinse with water after treatment, the dissolved minerals and other components are left on the tooth surface and combined with the sealer to form a mixed layer, and the presence of this stained layer (mixed layer) affects the resin penetration and reduces the retention force. The presence of this staining layer (mixed layer) affects the penetration of the resin and reduces the retention force. Full acid etching is a relatively complex procedure compared to self-etching and conventional sealing. After phosphoric acid etching, the enamel surface is evenly demineralized, resulting in a large number of microporous structures, which is beneficial for retention. After rinsing, the enamel surface microporous completely exposed, conducive to low viscosity, good fluidity of the bonding agent to fully penetrate between the enamel column, promoting the combination of the sulcus sealing material and the tooth surface, while these adhesives can also penetrate the deeper layer of small fissures, complementing the effect of closure. In addition, the bonding agent we now commonly use has hydrophilic properties, and the organic solvent-based primer with acetone as the carrier, while displacing the excess water on the enamel surface, promotes the hydrophilic monomer to penetrate into the enamel micropores, enhances the closeness between the sealant and the enamel, and reduces the gap between the sealant and the tooth tissue. The possibility of secondary caries is reduced. Fossa Enameloplasty Closure Fossa Enameloplasty Closure is tedious, long and requires high cooperation from the patient compared to the former. As we said before, there are different forms and depths of sulcus points in the jaw surface of teeth, and the degree of plaque and other substances in the sulcus also varies, in addition to the difference of mineralization of enamel structure in the sulcus, it is difficult to clean the sulcus thoroughly by general cleaning method, which will affect the effect of acid etching agent, so it is difficult for the sealant to enter the deep part of the sulcus completely, which affects the effect of sealing, for this reason, some foreign countries have proposed to prepare the sulcus by mechanical To enhance the permeability of the sealant in the sulcus and improve the effect of fossa closure, that is, fossa enamel forming closure EST. Advantages 1, EST change the inherent shape of the sulcus and expand the opening of the sulcus, which facilitates the cleaning of organic fillers and plaque, which is certain. 2.Increase the depth of resin penetration in the micropore after enamel etching 3.Enhance the bonding of the sealer to reduce the occurrence of microleakage. But this method is really perfect, is it really good? Let’s think about it, the operating group facing is children, adolescents, complex intra-oral operations will inevitably cause problems. In addition, when the teeth are mechanically polished, once the sulcus sealant falls off due to saliva contamination or other reasons, the possibility of forming caries later will be much higher if it cannot be repaired in time. UltraSealXT plus is a light-curing, image blocking, continuous release fluoride composite sealant. This composite sealant contains 58% filler, making it stronger, more wear-resistant, and has less polymerization shrinkage than comparable products. The shear dilution of the thixotropic UltraSealXTplus material by agitation of the auger brush delivery head causes the sealer to be drilled down during delivery. The shear-thinning action stops and the resin solidifies once it is in place, effectively preventing the sealer from flowing prior to light curing. The application of PrimaDry with UltraSealXT enhances the effectiveness of the sealer by eliminating moisture, making it easier for UltraSealXTplus to penetrate into the sulcus pits and prevent failure of the sealer. High quality sealant for deep sockets and early onset cavities that are susceptible to caries is beneficial at any age. Steps (1) Acid etching for 20 seconds, rinsing. The illustration shows the application of a spiral brush delivery head, a blue delivery head can also be used. (2) Blow dry and use PrimaDry drying medium. The illustration shows the application of a black FX conveying head, or a blue conveying head can be used to. (3) Apply UltraSealXTPlus fossa sealant. (4) Apply light curing and other irradiation.