A sealant is a thin, plastic coating applied to the chewing surface of molars, premolars and any deep grooves (called pits and fissures) of teeth. More than 75% of dental decay begins in these deep grooves. Teeth with these conditions are hard to clean and are very susceptible to decay. A sealant protects the tooth by sealing deep grooves, creating a smooth, easy to clean surface. Sealants can protect teeth from decay for many years, but need to be checked for wear and chipping at regular dental visits.