Sealants are protective coatings placed over the tops of the back teeth (molars). They block bacteria and acids from sticking in the tiny grooves on the chewing surfaces of these teeth. Sealants can be placed in adults and children. Children can have sealants placed on their permanent molars once they come in, around age six. Sometimes they are also used on primary (baby) molars. Dentists can put sealants on molars with signs of early decay, as long as the decay hasn’t broken through the enamel.