Effects of Mouth Breathing on Facial Skeletal Development in Children

Researchers reviewed 10 studies comparing the faces of children who breathe through their mouths to those who breathe through their noses. The differences were consistent and significant.

Children who mouth-breathe tend to develop longer, narrower faces — sometimes called "long face syndrome." Their jaws grow downward and backward instead of forward, their upper teeth push outward, and their airways get narrower. It creates a vicious cycle: the narrow airway makes mouth breathing worse, which makes the face grow even more in the wrong direction.

This matters because it shows that mouth breathing in childhood isn't just a habit — it physically changes the shape of a child's face. The earlier it's identified and addressed, the better the chance of guiding the face back toward healthy development. Left alone, these changes become permanent.