Sleep and Airway Screenings


Airway Screenings for Children

  • Do you have concerns about your child’s mouth breathing, snoring or sleep quality
  • Are they experiencing ongoing mouth breathing, teeth grinding or snoring after surgery to remove enlarged adenoids and tonsils?
  • Do you have concerns about ADHD-like symptoms in your child?

Mouth breathing and snoring in children are linked to unrestorative sleep, and increased risk of behavioural and learning problems down the track.

In 2017, the American Dental Association adopted a policy statement recognizing the important role of dentists in screening for airway problems and developing an optimal airway and breathing pattern.

Dr Lim is well trained in screening for these issues and is involved in a collaborative team approach to restoring proper airway structure and function for children.

For optimal sleep, brain development and daytime function, breathing should be silent and through the nose, and a sleeping child should look still and restful.

Here are some symptoms that may warrant further investigation of underlying breathing or airway problems.


The nose is especially designed to slow the flow of air and warm, humidify and filter pathogens and allergens in the incoming air before it enters the lungs.

Nasal breathing also promotes the release of nitric oxide in the paranasal sinuses and transports it to the lungs and blood, compared to mouth breathing where nitric oxide production in those sinuses is bypassed.

This important molecule plays many important roles throughout the body.

The first role as it passes down the upper airway is to act as a first line of defense against any microorganisms as it has strong antiviral and antimicrobial activity.

It is also a very potent vasodilator, which means that it relaxes the muscles walls of the blood vessels and promotes increased blood flow. This helps promote better gas exchange in the lungs and greater oxygenation to the body. It can even enhance sporting performance.

Breathing through the nostrils offers a slower passage of air compared to breathing through the mouth. This allows deeper breathing as air is drawn into the lungs. This may be helpful to promote a more relaxed state. It is also important for smell, and this has also been linked to better memory consolidation.

Nasal breathing is also important to activate reflexes that keep the throat muscles toned and the upper airway more stable during sleep.

Most of us will appreciate how sleep is less restorative and we feel less refreshed when we have a stuffy nose.

For some children who do not use their nose properly, this can result in a chronic deprivation of restorative sleep. These children may be exhausted, have poor concentration and attention at school. Some of these children may receive a diagnosis of ADHD. It can affect their learning potential and keep them from developing to their full potential.

Mouth breathing is the very earliest indicator a child may have a trajectory of increasing breathing difficulties like snoring or obstructive sleep apnoea down the track. This is also associated with increased risk of behavioural and learning problems.

Other problems can include:

  • Dry mouth, increased risk of bad breath and dental disease
  • Increased risk of upper airway infections including colds, sore throats and ear infections
  • Poor facial and palate development
  • Crooked teeth reflecting poor jaw development
  • Lowered tongue posture – tongue is more likely to obstruct the airway
  • Myofunctional disorders related to chronic open mouth posture – including speech, chewing and swallowing problems
  • Forward head posture and chronic neck and shoulder tension

One of the ultimate problems is that if mouth breathing is not properly addressed in childhood, it leads to poor facial and jaw development.

This negatively impacts their airway development and breathing into adulthood and increases risk of obstructive sleep breathing into adulthood.

By age 6 years, 60% of the adult sized face has been attained.

The best time to address mouth breathing is as early as possible, whilst a child’s facial structures are still developing.

Form follows function.

The way the muscles of the mouth and face rest and move during function play have a very big influence on the way a child’s facial structures grow.

If the lips rest apart, the lower jaw tends to rotate down and back, and the tongue posture tends to lower.

The face tends to grow more vertically than project forward and the tongue is unable to provide the proper stimulus for proper development of palate width.

The most severe expression of this facial pattern is sometimes referred to as the adenoid facies or the long face syndrome. It was called adenoid facies as it was originally observed in children with chronic nasal obstruction related to enlarged adenoids. However, this pattern can be observed in children with nasal congestion related to allergies or even open mouth posture related to muscular dystrophies or low tone open mouth posture from infancy – e.g. with premature infants.

Most of the time, the deficits are more subtle, but open mouth and low tongue posture will leave some type of indelible stamp on their development. This is especially if mouth breathing occurs during sleep where children spend the most significant amount of time in early childhood.

It is ideal for children to breathe through their nose during the day, and no less than 4% of the night.

But many parents do not check their child regularly during the night so are not able to confirm if things are completely normal.

Parents may be able to look for:

  • Dark circles under the eyes
  • Dry, chapped lips
  • Flaccid lips
  • Open mouth posture
  • Inability to seal the lips together without strain
  • The appearance of a golf ball chin due to overactivity of the muscle in the chin when the lips are sealed
  • Drooling or perio-oral dermatitis
  • Low tongue posture or tongue thrust
  • Long narrow face
  • Receded jaws or flattened cheekbones
  • Narrow pinched nostrils
  • Forward head posture
  • Hyponasal voice
  • Audible nasal breathing
  • Shallow breathing with movement of the upper body rather than belly breathing

Generally speaking the causes can be categorised into three main groups, and there may be multiple factors present in a single child.

  • Obstructive – inside the airway – allergies and nasal congestion, enlarged adenoids and tonsils, deviated septums
  • Structural contribution of the palate – narrow high palates are linked to narrow nasal floor, reduced cross-sectional area of the nasal airway and increased resistance to nasal airflow. If mouth is too narrow then the tongue can’t fit properly, making it more comfortable to keep the mouth open
  • Muscle factors – habit – observed from other family members, or if mouth has been chronically open, the jaw is slack, the lips flaccid the tongue sits low, the nose has been dis-used – it all needs training with myofunctional therapy

Recent evidence has implicated tongue tie in mouth breathing and the development of obstructive sleep breathing in later childhood.

At rest and during sleep, the entire top surface of the tongue should be sufficiently toned to suction to the palate. In this position, it is impossible to mouth breathe and mechanically easier for the lower jaw to close, thus promoting nasal breathing.

When the tongue is tied, or its mobility is abnormally restricted, it tends to sit low and the mouth breathing route is not properly sealed. When the tongue sits low, it is more likely to encroach into the airway and the mouth may open in compensation to allow airflow.

Myofunctional therapy is aimed to re-establish closed mouth nasal breathing and tongue to palate seal at rest and proper tone, coordination and endurance of the tongue and other throat muscles. Research suggests it is an important adjunct and critical missing link to restoring nasal breathing after other interventions like surgery and palate expansion.

Tongue tie release will not restore nasal breathing as a standalone procedure. However, it can be considered as an adjunct to facilitate more effective myofunctional therapy.

Evidence has implicated tongue tie and low resting posture as contributors to underdevelopment of the palate or nasal floor. This has been linked to nasal disuse and the development of obstructive sleep breathing in later childhood as a result.

Because it is often a multifactorial problem and has a wide range of consequences, it will often require a combination of approaches.

This can include:

  • ENT referral to rule out obstructions within the airway – this most commonly includes enlarged adenoids and tonsils, enlarged turbinates, and deviated septums
  • Orthodontic treatment to widen the palate/nasal passages and improve tongue space
  • Myofunctional therapy to restore more normal muscle patterns including restoring closed mouth, nasal breathing with tongue to palate seal
  • Allergy management

At initial consultation, Dr Lim will take a full functional history including asking detailed questions about your child’s sleep and suggest a plan based on their individual findings.

OSA is a condition characterised by complete or partial blockages of the airway that last 10 seconds or more and dips in blood oxygenation.

Diagnosis requires an overnight sleep study demonstrating that these ten second obstructions occur at least once per hour of sleep. It is estimated that up to 10% of children have this condition, making it as prevalent as childhood asthma.

Up to 85% of children with OSA have not had this diagnosed but this is just the tip of the iceberg.

OSA is the most severe condition of a spectrum of breathing difficulties called Obstructive Sleep Disturbed Breathing. These are all related to a narrowing of the airway and increased resistance to normal airflow when breathing during sleep.

The reality is the vast majority of children are able to compensate for restricted airways by open mouth breathing, teeth grinding, tossing and turning, sleeping with their neck hyperextended or on their stomach, or working harder to breathe. This means that they tend not to have the prolonged collapses of the airway, and oxygen levels are not interrupted. However, this still can result in significant sleep fragmentation and chronic overactivation of the sympathetic nervous system or “fight or flight response.” Sleep is very fragmented and unrestorative.

Nasal breathing is a key pillar for good sleep, health and learning. Mouth breathing may be the very earliest indicator that breathing is not normal.

There are many risks related to sleep fragmentation, oxygen deprivation, increased work of breathing and chronic stress. These can include increased risk of:

  • High blood pressure and other cardiovascular problems
  • Metabolic disease
  • Poor growth – related to reduced growth hormone which is secreted in deep sleep
  • Increased risk of neurocognitive and behavioural problems
  • Speech and language concerns Bedwetting
  • Poor facial development

In general, for the non-obese child, the most significant risk will be the impact on the developing brain and their behaviour and learning potential.


Snoring and other breathing difficulties during sleep result in fragmented and non restorative sleep. In comparison to an adult who may feel tired, a sleepy child may present with symptoms of overtiredness. They may have troubles with hyperactivity, concentration and attention or be prone to tantrums, meltdowns, defiance and aggression. Some of these children may be diagnosed with ADHD.

To avoid misdiagnosis, it will be important that poor sleep and breathing is investigated before prescription of stimulant medication. Other children may display anxiety or symptoms of depression.

There is even some research to suggest that obstructive sleep breathing affects the amygdala, a part of the brain important for empathy. This deficit has been implicated in bullying. This can lead to difficulties with concentration and attention and other behavioural problems including hyperactivity, tantrums and meltdowns, defiance, aggression, anxiety or even symptoms of depression.

Landmark research by Bonuck and team examined 11,000 children. The results suggest that around 30 months seems to be a time when children’s brains are particularly vulnerable to persistent behavioural deficits.

They found that children who had peak mouth breathing, snoring and gasping during sleep at 30 months had 2x the risk of behavioural problems by age 7, even though they had grown out of breathing difficulties by the 42 month mark.

They concluded we should pay attention to symptoms like mouth breathing, snoring and gasping during sleep from the first year of life. Rather than children growing out of the problem, they may actually be growing into it.

There have been several studies using MRI that have shown that snoring is linked to losses of the brain’s grey matter. One of the most significant included over 10,000 children (aged 9-10) enrolled in the Adolescent Brain Cognitive Development (ABCD) study.

MRI scans of their brain structures were evaluated along with sleep and behavioural questionnaires completed by the parents. Controlling for confounding factors, researchers established there that there was a strong link between sleep breathing and behavioural problems was mediated by losses of grey matter in multiple regions of the frontal lobe of the brain.

It does not mean every child who snores will be affected in the same way. But it does suggest there is something very detrimental that is going on in the brain, and it is not certain how reversible it is.`

Obstructive sleep breathing is the result of a complex interplay of factors including small or restricted airways combined with reduced muscle tone of the tongue and upper airway muscles during sleep, reduced reflexes that normally keep the airway open during the day, and the impacts of gravity on the tongue and throat tissues when lying down during sleep.

The underlying poor airway structure can result from:

  • excess soft tissue inside the airway such as swelling from allergies and other inflammation, and enlarged adenoids and tonsils
  • small or underdeveloped jaws that form the outer borders or structural support of the upper airway
  • the tone of the muscles that keep the upper airway open (poor muscle patterns include open mouth and low tongue posture).

As health care professionals focused on prevention, we are seeing children most often on a regular six-to-twelve-month basis and children often see us more than a general medical doctor.

There are also many clues in the mouth and face that could indicate restricted airway and increased risk of obstructive sleep breathing. We are perfectly positioned to screen for these during our regular checks.

Clues include:

  • Obesity or delayed growth
  • Dark circles under the eyes
  • Forward head posture
  • Open mouth posture
  • Lips unable to close without strain
  • Narrow nasal passages
  • Nasal congestion or audible breathing through the nose
  • High and narrow palate
  • Receded lower jaw
  • Tooth wear related to teeth grinding or reflux disease
  • Lack of dental spacing or crowding of baby teeth
  • Dental crossbites
  • Enlarged tonsils
  • Visualising the degree of crowding at the back of the throat
  • Low tongue posture
  • Tongue ties
  • Restricted tongue mobility

If your dentist notices these in combination symptoms of disturb sleep they may refer you to an ENT surgeon and have an important role to play in the team management of these problems.

Adenoids and tonsils are masses of immune tissue in the throat in the area behind the nose and soft palate. They trap bacteria and viruses and mouth and contain immune cells that produce antibodies which help prevent infection from spreading in the body.

Sometimes, these tissues become so swollen they obstruct the airway and contribute to disturbed breathing during sleep. In this case they become more of a liability than an asset, and surgical removal may have to be considered.

Surgical removal of adenoids and tonsils can allow a return to more normal breathing. The adenoids and tonsils do tend to shrink with age, but this is not necessarily a reason to avoid surgery. When children snore, they may more accurately grow into it rather than out of it.

This is because of the potential for persistent increased risks of behavioural problems. Research also suggests that even when removed, some children may have a learning debt that may hamper subsequent school performance.

Your ENT surgeon should weigh up your child’s individual risks and benefits to help you decide whether this is the right option. Many children will have improvements in their day and night symptoms of sleep disturbed breathing.

Research comparing objective sleep breathing outcomes after surgery suggests that up to 73% of children will not have a complete resolution of breathing problems. Further research suggests that many children who have improvement will have a recurrence of problems later in childhood.

This suggests adenotonsillectomy is not the cure it was once thought to be. It also reinforces that obstructive sleep disturbed breathing is a multifactorial problem and that long term resolution must involve a team to address all risk factors. The ultimate goal should be to restore closed mouth, tongue up, nasal breathing.

An airway focused dentist will be able to assess the jaw structures and how the muscles of the mouth and face are resting and functioning. Narrow high palates and low tongue tone are both common risk factors for sleep disturbed breathing.

Dental professionals trained in orthodontics or myofunctional therapy can play a role in targeting these factors. Palate expansion to address narrow nasal floor and tongue space is well supported as an adjunct to reduce snoring and obstructive breathing, as well as help address impaired nasal breathing.

Myofunctional therapy addresses the muscle deficits that may have occurred along with chronic mouth breathing. These deficits include open mouth posture, poor lip seal, low tongue posture and tone and reverse swallowing.

The therapy involves creating awareness of proper muscle patterns and exercises to restore closed mouth nasal breathing and proper tone, co-ordination and endurance of the tongue and upper airway muscles.

Research suggests myofunctional therapy and restoring nasal breathing during the day and night is a critical missing link after interventions like surgery and palate expansion which open up the airway.

Tongue tie release may sometimes be necessary to facilitate better therapy, and restore tongue to palate seal during sleep. In some cases, children will also require investigation of allergies in conjunction with these options.

You can book them in for a consultation to assess snoring and other factors such as narrow palates, and low tongue tone.

Dr Lim can coordinate a direct referral to an ENT specialist as required and give you an indication of what is required to restore all other risk factors and re-establish closed mouth, tongue up nasal breathing.

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