Mouth breathing in children is more than a breathing habit. When it persists, particularly during the years of facial growth, it may be associated with changes in dental and facial development. Research has linked habitual mouth breathing with altered jaw relationships, increased vertical facial dimensions, changes in incisor position, narrower dental arches and certain types of malocclusion.

Why does mouth breathing happen?

Children may breathe through their mouth because of nasal obstruction, enlarged adenoids or tonsils, allergies, nasal congestion, or other airway-related problems. The underlying cause should be evaluated rather than simply treating the habit.

What can you look out for?

Some signs that may warrant an evaluation include:

  • Frequently sleeping with the mouth open
  • Difficulty breathing through the nose
  • Snoring or restless sleep
  • Dry mouth
  • Lips that don't comfortably meet at rest
  • Crowding or altered bite
  • Narrow or high-arched palate

These signs don't necessarily mean that a child has a growth problem, but persistent mouth breathing deserves assessment.

Why early evaluation matters

The growing face is dynamic. Identifying airway, breathing and orthodontic concerns early can help the dental and medical team understand whether intervention is appropriate. Depending on the cause, management may involve an ENT evaluation, treatment of nasal obstruction, orthodontic assessment, or a combination of approaches. Evidence also suggests that correcting the underlying breathing problem may be accompanied by favourable dental adaptations, although complete correction of facial growth changes cannot be guaranteed.

If your child is a persistent mouth breather, don't wait for the teeth to become crowded. An early orthodontic evaluation can help identify potential concerns while the face and jaws are still developing.

Supporting articles

  • Effects of mouth breathing on facial skeletal development in children - systematic review & meta-analysis
  • Mouth breathing in children and its impact on dental malocclusion - systematic review
  • Mouth Breathing and Craniofacial Development in Children - 2026 review
  • Impact of rapid maxillary expansion on mouth-breathing children - systematic review
  • Mouth Breathing in Children: How It Can Affect Facial Growth and Why Early Orthodontic Evaluation Matters