For children and young adults, the most common place that cavities form is on the biting surface of the back teeth. The pits and grooves on molars can be deep, trapping bacteria and debris that can cause decay even with the best brushing habits. Fortunately we have dental sealants for these cases.
Sealants are thin layers of resin that are placed in the grooves of molars, providing a barrier to the decay-causing bacteria from attacking the tooth.
Sealants are very effective at minimizing the decay risk. Not all molars in children need sealants however, just those that have moderate to deep anatomical grooves.
Typically this determination is made shortly after the molars have erupted, usually around ages 6 and 12.