UltraSeal XT hydro?is a light-cured, radiopaque, fluoride-releasing composite sealant. It is stronger and more wear resistant because it is a 53%-filled resin and has less polymerization shrinkage than competitive products. The spiral brush action of the Inspiral??Brush tip causes shear thinning of the filled, thixotropic UltraSeal XT hydro, reducing its viscosity as it is placed. The resin firms when shear thinning ceases and placement is complete, preventing it from running before it can be light cured. The hydrophilic chemistry with its characteristic thixotropic nature chases moisture (that in hydrophobic sealants can cause sealant failure) deep into the pits and fissures on a microscopic level. Once there, the advanced adhesive technology securely bonds the sealant to the enamel, increasing marginal retention and reducing microleakage.