Try as you may, many parents fail to get their children to brush their teeth as they should. Children do okay with their front teeth, but brushing their back teeth are often difficult to reach properly. Tooth decay occurs quickly when children do not do a good job brushing over a period of time. Food particles and plaque get into the grooves and cause cavities. Dental sealants are part of preventative dentistry. They are made to keep those particles from getting into the cracks and prevent decay.