Thumb sucking in young children is a normal response to anxiety and stress. Still, this behavior should decrease by ages 2-4 and stop by age five. Many children are slow to break the habit, which can lead to anxiety for parents. Is it worth the stress to break the thumb sucking habit? Yes, because long-term thumb sucking can cause chewing difficulties, speech abnormalities, and dental problems.

The longer and harder a child sucks their thumb the more harm is done to the teeth and jaws. Regular, strong thumb sucking makes front teeth move and can even reshape the jaw bone. Upper front teeth flare out and tip upward while lower front teeth move back and inward. But, how can something as small as a child's thumb or finger actually move bone?

Children’s jaws are rich in blood supply and fairly low in mineral content like calcium. This makes jaws of children under age eight especially soft and flexible. As a result, prolonged thumb or finger sucking easily deforms the bone around the upper and lower front teeth. The deformity produces a hole or gap when teeth are brought together, known as an open bite.

If a child stops thumb sucking before the loss of baby front teeth and the arrival of adult front teeth, most or all of the damage may disappear. However, if the habit persists, there may be lasting damage.