A child has 20 baby teeth, as opposed to an adult's 32 permanent teeth. So, there might be less of them (and obviously they're smaller than yours), but aside from this, aren't your child's teeth more-or-less the same as yours? There are certain significant differences, which can be important if your child ever starts to complain about sensitive teeth.
Your Child's Teeth
Apart from the reduced number and size, it might seem that there's little difference between your permanent teeth and your child's baby teeth. The composition of a primary baby tooth is in fact somewhat different to a secondary adult tooth, particularly when it comes to dental enamel—the strong, heavily-mineralized protective outer layer of the tooth.
A child's dental enamel is naturally thinner and softer than an adult's. This means that their enamel is less resistant to the corrosive effects of tooth decay. As the enamel thins, the underlying tooth dentin becomes exposed. Once this has happened, the nerve at the center of the tooth becomes more sensitive to external stimuli, such as the temperature of food and drink, and even the pressure of chewing. This sensitivity is in addition to the tooth's increasing vulnerability to decay. If your child says that their teeth are becoming more and more sensitive, you need to schedule an appointment with your family dentist.
Your family dentist will take a look at your child's teeth, since a visual inspection is often enough to spot thinning dental enamel. It shows up as a discolored patch on the tooth's surface. Diagnostic tools can also be used, if needed. Your dentist may quiz you about your child's diet and oral hygiene practices, and some changes might be recommended. However, your dentist won't expect your child to just live with their tooth sensitivity until their baby teeth are replaced by adult teeth.
Sealing the Tooth
There are several measures which can help to reduce your child's sensitivity. Dental sealants are a practical approach. This is a transparent latex coating painted onto teeth, which reinforces the enamel by filling in any thinning areas. Dental sealants require no special care (just brush the teeth as normal), and can easily be reapplied as needed during your child's regular checkups. The sealant will quite literally seal your child's tooth dentin, which should reduce their sensitivity.
Dental sensitivity can easily become something far more serious as the tooth continues to deteriorate, which is why it's best to have your child's sensitive teeth investigated by your dentist before these more serious problems can develop.