Protecting teeth to prevent tooth decay What is a gash sealant? A sealant is a protective resin film applied to the occlusal surface of a child’s permanent teeth. The sealant fills the grooves in the teeth and prevents bacteria from entering, thus creating a protective barrier. Why do children need to have their sockets closed? Most cavities are on the occlusal surfaces of the back teeth, where food and bacteria are hidden in small pockets and grooves smaller than a toothbrush with no way to clean them out. Most dentists recommend sealing the molars and bicuspids of the permanent teeth because the fossa of the molars are deeper and the milk teeth usually do not need to be fossilized. Some children are prone to cavities and the dentist may recommend sealing the molars of the baby teeth.