The most likely location for a cavity to develop in your child's mouth is on the chewing surfaces of the back teeth which are not smooth, as other areas of your teeth are. Instead, they have tiny grooves referred to as “pits and fissures,” that traps food and becomes a home to certain bacteria. If not brushed properly, as not expected by a young buddy, creates a perfect environment for tooth decay. What's more, a child's newly erupted permanent teeth are not as resistant to decay as adult teeth are. The hard enamel coating that protects the teeth changes as it ages to become stronger. Dental sealants are invisible plastic resin coatings that smooth out the chewing surfaces of the back teeth, making them resistant to decay. A sealed tooth is far less likely to develop a cavity, preventing requirements for extensive dental treatments later on.