Sealants are used to “seal out” food, plaque and acid from the grooved and pitted surfaces of the teeth. They are typically applied to the surfaces of back teeth where most cavities in children are found. Made of shaded plastic, sealants do not require numbing of the teeth during application. While sealants can last up to 4 years, they must be properly cared for with good oral hygiene and by avoiding hard objects.