Sealants are hard coatings that are placed on the biting surfaces of a child's permanent posterior (back) teeth. They are comfortably placed without the need for anesthesia (numbness). Sealants virtually cover the narrow grooves and pits in these teeth protecting the underlying enamel. Sealants also contain fluoride that is released over time into the enamel, further strengthening it from breakdown. The best time to apply sealants is when the crown of the permanent tooth has just erupted.