Chewing teeth can have deep and narrow grooves. Deep grooves are difficult to clean and are vulnerable to decay. To prevent this, fissure sealants are applied on the teeth to block the grooves and to act as a barrier between the tooth and bacteria/food/plaque. The dentist will thoroughly clean the tooth using a special solution and apply the sealant. The process is usually fast and it takes only a few minutes. Sealant usually last for years and can be reapplied if needed.