Girl with orthodontic issues due to mouth breathing

Mouth breathing: The adverse effects on facial growth, health, learning and behaviour

The effects of mouth breathing in childrenFew parents realize how malleable the facial bones of a six-year-old child are and how quickly habits such as leaving the mouth open or thumb-sucking can spoil a child’s appearance for ever.

It is difficult for a lay person to know if the face of a young child is growing correctly, because most young children look ‘cute’. However, mouth breathing and poor tongue posture can result in a long face with a narrow upper jaw and crowded teeth.

The upper jaw stops growing in most boys and girls before the age of 10. Hence early treatment is the key.

It is important to not just straighten teeth with braces but also to ensure correct tongue posture and nasal breathing before the orthodontic treatment is completed.

Mouth breathing - the adverse effects in childrenOne of the main causes of relapse of orthodontic treatment is when the main cause of malocclusion (incorrect tongue posture or mouth breathing) is not treated, and only the teeth are straightened.

Causes and symptoms of mouth breathing

One of the main causes of mouth breathing in children is allergies and blocked noses caused by enlarged adenoids and tonsils.

Here is an image of a young boy with normal breathing and a balanced facial profile to begin with, until he was introduced to an allergen (possibly the family cat). This led him to breathe through his mouth and end up with a long face, with crowded upper and lower jaws.

Effects of mouth breathing


The following are some of the symptoms that may be experienced by a child who is not breathing correctly or has sleep apnoea:

  • Dark translucent areas under eyes
  • Behavioural problems
  • Inability to focus in class
  • Bed wetting after the age of 6 yrs
  • Feeling tired and easily falling asleep during the day
  • Snoring , teeth grinding and night sweats

Mouth breathing is associated with high blood pressure and cardiac failures

Nasal respiration is responsible for the production of nitric oxide. This nitric oxide, inhaled via the nasal respiration, is known to increase oxygen exchange efficiency and increase blood oxygen by 18% while improving the lung’s ability to absorb oxygen. Nitric oxide is also a strong vasodilator and brain transmitter that increases oxygen transport throughout the body and is vital to all body organs including smooth muscles of the heart and blood vessels.

The negative impact of sleep disordered breathing in children’s growth and development is well documented

These children are often well below their peers in terms of height and weight. Sleep apnoea is on the rise in both adults and children.

A child with sleep apnoea may often get misdiagnosed with attention deficit hyperactivity disorder (ADHD). Mouth breathing often irritates the mucosa and often causes the tonsils and adenoids to enlarge. These may need to be removed surgically when they obstruct the airway and negatively affect sleep.

Treatment options for children with a crowded mouth and narrow jaws

Correct oral posture

Showing how the face improves if the oral posture is corrected.

Treatment normally involves a jaw expansion device and associated treatments to address tongue, breathing and body alignment issues.

Jaw expansion appliances

These can be removable or fixed. The appliances include the ALF appliance, Schwartz plate, and the hirax and myofunctional appliances.

A slow expansion achieved over 6-9 months is ideal. Rapid expansion is also occasionally done, using fixed appliances.

Jaw expansion applianceJaw expansion appliance

Associated treatments

  • Most patients with a narrow jaw need help with an Oral Mycologist/Respiratory physiotherapist to retrain the tongue to sit up on the palate instead of being on the lower teeth.
  • Patients who are mouth breathers need breathing retraining, and in that process their posture and head posture improves.
  • Occasionally some patients may need orthotics by a podiatrist to correct the overall posture, helping to keep the oral expansion stable.
  • In cases where the adenoids and tonsils are excessively enlarged and blocking the airway an Ear Nose and Throat specialist may be required.

Dr Urvashi Pandey

Dr Urvashi PandeyDr Urvashi Pandey was born in Dharamsala in northern India. She graduated in dentistry in 1996 and was in private practice before moving to Australia in 2001. Dr Urvashi is known for her patience, attention to detail, and her gentle and approachable nature. She believes that good dentistry is a blend of creativity, modern techniques and vision, and follows a holistic approach to diagnosis and treatment.

View full profile