Dental sealants are thin coatings that when painted on the chewing surfaces of the back teeth (molars) can prevent cavities (tooth decay) for many years. Sealants protect the chewing surfaces from cavities by covering them with a protective shield that blocks out germs and food. Once applied, sealants protect against 80% of cavities for 2 years and continue to protect against 50% of cavities for up to 4 years. Most often, the sealants are applied to the back teeth, e.g., premolars and molars.