Permanent molars sometimes have deep grooves and pits in the chewing surfaces that are difficult to clean with a toothbrush. To prevent cavities, these grooves and pits can be filled with a fissure varnish. This is called sealing. By sealing the molars, bacteria have less chance to penetrate your molars. We often seal molars in children when the adult molars come through, but it can also happen in adults when deep grooves and pits are present. By sealing them, you reduce the risk of tooth decay.