A sealant is a clear or tinted plastic protective coating for teeth. It is painted onto the chewing surfaces of the back teeth (molars and premolars). These are the areas where most cavities form. Molars and premolars have grooves and crevices. We call these pits and fissures. Food can get stuck in these crevices. Some are so deep that the bristles of a toothbrush can't reach into them. Grooves and crevices provide the perfect environment for bacteria to grow and cause cavities. Sealants help to prevent this from happening. They cover the grooves and crevices so that food cannot get into them. The entire procedure takes about 20-30 mins.