Sealants consist of a plastic resin placed on the chewing surface of the permanent back teeth to help protect them from bacteria and acids that cause tooth decay. The plastic resin is placed into the depressions and grooves of the teeth and a light is used to cure it to the enamel which protects the enamel from plaque and acids.
Proper brushing and flossing removes food debris and plaque from the smooth surfaces of teeth, but toothbrushes can't reach all the areas causing plaque to accumulate in hard-to-reach areas. The acid from bacteria in the plaque attacks the enamel, causing cavities to develop. While fluoride helps protect the surfaces of the teeth to prevent decay, sealants provide extra protection for the grooved and pitted areas. Sealants protect these vulnerable areas by "sealing out" plaque and food debris from the chewing surfaces of the teeth.