Dental sealants are plastic coatings that are usually placed on the chewing (occlusal) surface of the permanent back teeth — the molars and premolars — to help protect them from decay.
The chewing surfaces of the molar and premolar teeth have grooves — "fissures" — that make them vulnerable to decay. These fissures can be deep, are difficult to clean, and can be narrower than even a single bristle of a toothbrush. Plaqueaccumulates in these areas, and the acid from bacteria in the plaque attacks the enamel and cavities can develop. Fluoride helps prevent decay and helps protect all the surfaces of the teeth, dental sealants provide extra protection for the grooved and pitted areas by providing a smooth surface covering over the fissured area.
Dental sealants are usually placed on the chewing surfaces of these teeth because these are the areas and teeth that typically have deep fissures. Dental sealants are sometimes also used on other permanent teeth if they have grooves or pits, to help protect these surfaces.