Sealants protect grooves and pits on teeth. They are on a forefront of preventative dentistry. With this simple solution a lot of teeth can be saved and be protected from a dentist drill. The food and bacteria known together as plaque, need a retention surface in order to survive and proliferate jeopardizing tooth structure. A sealant is a way of preventing that.
Some teeth anatomically are made in a way that the grooves on them are very deep and extremely narrow so bacteria can easily be moved there, but not the bristles of a toothbrush. With enough time acid is being build up as the result of bacterial metabolism, the enamel undergoes hypo-calcification, till it is penetrated all the way to the dentin, that lies underneath. To protect enamel from invasion of bacteria, tooth have to be cleaned and polished from the debris to ensure maximum retention and a layer of composite resin is placed in those grooves and pits to protect the solid tooth structure.
Sealants are usually placed on children up to age 14 and only on permanent molars, but any tooth at any age would benefit from this type of preventive measure.