This can be used in varying strengths, but the most commonly used strength is 37 percent. The acid etch serves several purposes. It removes debris from the tooth surface, provides better wetting capability of the enamel for the resin and selects dissolution of the enamel surface. Enamel is normally porous but etching does remove some of the calcium salts to increase microspaces. If a surface of enamel inadvertently is etched, generally polishing the enamel surface is sufficient to repair this area.
Sealants vary somewhat in their longevity.
Part of this depends upon the bond achieved. Isolation and a dry area are needed to achieve a solid bond. The tooth location and patient hygiene habits also influence how long sealants will last. Chewing ice and sticky foods may decrease the life of sealant. Every patient who has had sealants placed should be examined when they return for hygiene visits.