The most likely location for a cavity to develop in your child's mouth is on the chewing surfaces of the back teeth. Run your tongue over this area in your mouth, and you will feel the reason why: These surfaces are not smooth, as other areas of your teeth are. Instead, they are filled with tiny grooves referred to as “pits and fissures,” which trap bacteria and food particles. The bristles on a toothbrush can't always reach all the way into these dark, moist little crevices. This creates the perfect conditions 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. Fluoride, which is found in toothpaste and some drinking water — and in treatments provided at the dental office — can strengthen enamel, but, again, it's hard to get fluoride into those pits and fissures on a regular basis. Fortunately, there is a good solution to this problem: dental sealants.

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, require more expensive dental treatment later on, or, most importantly, cause your child pain.

You can think of a sealant as a mini plastic filling, though please reassure your child that it doesn't “count” as having a cavity filled. Because tooth enamel does not contain any nerves, placing a sealant is painless and does not routinely require numbing shots. First, the tooth or teeth to be sealed are examined, and if any minimal decay is found, it will be gently removed. The tooth will then be cleaned and dried. Then a solution that will slightly roughen or “etch” the surface is applied, to make the sealing material adhere better. The tooth is then rinsed and dried again. The sealant is then painted on the tooth in liquid form and hardens in about a minute, sometimes with the help of a special curing light. That's all there is to it!

A note about BPA: A 2012 study that received wide press coverage raised concerns that trace amounts of the chemical bisphenol-A (BPA) found in some (but not all) dental resins might contribute to behavioral problems in children. The study authors noted that while they had found an association, they had not actually proven that BPA in dental sealants causes these problems. In fact, BPA is far more prevalent in food and beverage packaging than in dental restorative materials. The American Academy of Pediatric Dentistry and the American Dental Association have since reaffirmed their support for the use of sealants.