Dental sealants (also termed pit and fissure sealants, or simply fissure sealants) are a dental treatment intended to prevent tooth decay. Teeth have recesses on their biting surfaces; the back teeth have fissures (grooves) and some front teeth have cingulum pits. It is these pits and fissures which are most vulnerable to tooth decay, partly because food sticks in them and they are hard to clean areas. Dental sealants are materials placed in these pits and fissures to fill them in, creating a smooth surface that is easy to clean. Dental sealants are mainly used in children who are at higher risk of tooth decay, and typically they are placed as soon as the adult molar teeth come through.