Fissure sealants are a preventative treatment commonly recommended on the back molars. Molars typically have deep grooves that are so narrow your tooth brush bristles cant quite keep food particles and plaque from getting trapped. If left, these particles allow bacteria to feed and produce acid, causing tooth decay. The sealant material is a flowable resin that fills in the deep grooves to prevent food debris and plaque from becoming stuck and allows you to brush more effectively.