A sealant is a protective plastic coating that’s applied to the chewing surface of back teeth, sealing off the grooves and crannies that tend to collect food. The sealant protects tooth enamel from plaque and acid. Sealants can help both children and adults. The Centers for Disease Control and Prevention recommends sealants for all school-age children. Sealants last up to 10 years before they need to be replaced, though they need to be checked regularly to ensure they’re still intact.