Dental sealants act as a barrier to prevent cavities. They are a plastic material usually applied to the chewing surfaces of the back teeth (premolars and molars) where decay occurs most often.
Thorough brushing and flossing help remove food particles and plaque from smooth surfaces of teeth. But toothbrush bristles cannot reach all the way into the depressions and grooves to extract food and plaque. Sealants protect these vulnerable areas by “sealing out” plaque and food.
Sealants are easy for your dentist to apply. The sealant is painted onto the tooth enamel, where it bonds directly to the tooth and hardens. This plastic resin bonds into the depressions and grooves (pits and fissures) of the chewing surfaces of back teeth. The sealant acts as a barrier, protecting enamel from plaque and acids. As long as the sealant remains intact, the tooth surface will be protected from decay. Sealants hold up well under the force of normal chewing and may last several years before a reapplication is needed. During your regular dental visits, your dentist will check the condition of the sealants and reapply them when necessary.
The likelihood of developing pit and fissure decay begins early in life, so children and teenagers are obvious candidates. But adults can benefit from sealants as well. 
