A sealant is a clear or shaded white plastic material that is applied to the chewing surfaces (grooves) of the back teeth (premolars and molars), where 80% of decay happens on adult teeth. The sealant acts as a barrier to food, plaque and acid, thus protecting the decay-prone areas of the teeth. Studies have shown that sealants can reduce tooth decay by as much as 90%.The American Dental Association (ADA) recommends that sealants be placed as soon as the first adult molars come in at age 6 or 7. Sealants should continue to be used as each adult molar tooth appears the mouth.