Sealants are plastic coatings that are put on the hard to reach dips and grooves of the teeth. This protects the teeth from bacteria that causes cavities and tooth decay. It is a painless and easy process done at the office. The sealant is placed on the chewing surfaces of permanent molars as soon as they have fully erupted in the mouth. That usually happens between the ages of 6 to 8 for first molars and 10 to 12 for second molars.