By some accounts, 80% of tooth decay begins in the pits and fissures of teeth. Toothbrush bristles may not be able to completely remove food from those areas.
Dental sealants and fissurotomy techniques may help protect against these types of cavities.
This animation opens by describing the epidemic nature of pit and fissure cavities, and the impetus for their prevention.
Pits and fissures are shown in cross-section, and dissolution of tooth enamel in the inaccessible fissures is illustrated- ultimately progressing to caries in dentin.