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Mouth Breathing Can Alter Facial Growth

A growing child can sustain permanent damage by breathing improperly.

What determines the growth of your child’s face? The debate between supporters of the genetic hypothesis (inherited traits) and those in favor of environmental influences (i.e., mouth breathing) is both old and not entirely resolved. Inheritance is a basic and primary consideration for all facial growth.

However, research in growth centers in Europe, Canada and the United States has shown that chronic mouth breathing contributes directly to facial growth changes in children. These changes should be considered as both abnormal and sometimes harmful to the growing bones and muscles of the face.

Breath to humans is similar to sun light to a tree. Both are necessary for normal growth and to sustain life. If a tree receives sunlight from only one direction, the trunk and branches grow toward the light source, and the tree will become permanently de formed.

If a child is unable to maintain a consistently health nasal airway, the body will automatically program the system to take breaths through the mouth. As with the trees, the entire system must adapt to survive.


Why is Mouth Breathing Harmful?

The adaptation from nasal to mouth breathing allows a number of unhealthy things to happen. These changes can include chronic middle ear infections, sinusitis, upper airway infections and sleep disturbances such as snoring.

In addition, mouth breathing is often associated with a decrease in oxygen intake into the lungs which can lead to a lack of energy. Mouth breathing children may fatigue easily during exercise.

Mouth breathing can particularly affect the growing face. The alterations will occur in the muscles associated with the face, jaws, tongue and neck.

The abnormal pull of these muscle groups on bones of the face and jaws slowly deforms these bones, eventually causing the jaws and teeth to be mismatched. The earlier in life these changes take place, the greater the alterations in facial growth

The largest increments of growth occur during the earliest years of life. In the first six months of life, the child’s weight doubles and in the first three years of life, height doubles– something that never occurs again in a similar span of time.

By age four the facial skeleton has reached 60 percent of its adult size, and by twelve, the age many orthodontists initiate treatment, 90 percent of facial growth has already occurred. Consequently, if a child has chronic nasal obstruction during the early critical growing years, facial deformities result, some subtle, some more noticeable.


What Changes Take Place?

In adapting the mouth for chronic respiration, two basic changes take place: the upper lip is raised and the lower jaw is maintained in an open posture.

The tongue, which is normally placed near the roof of the mouth, drops to the floor of the mouth and protrudes to allow a greater volume of air into the back of the throat. Consequently, many mouth breathers also exhibit an abnormal swallowing pattern.

As a result of these abnormal functions, children who are mouth breathers are at risk of developing a well-documented facial type commonly referred to as “adenoid faces,” or long-face syndrome (see figure below).

These individuals can be characterized by an open mouth posture, nostrils that are small and poorly developed, a short upper lip, a toothy or gummy smile and (as a result of the hanging posture of the lower jaw) a vacant facial expression.

Because there are abnormal muscular forces on the jaws, tooth positions can also be affected and are often malposed. Figure 1 demonstrates a severe malocclusion (bad bite) which includes severe dental crowding and a crossbite where the upper jaw is underdeveloped and fits inside the lower jaw.

Untreated airway problems may so severely affect facial growth that orthodontics alone cannot correct the malocclusion. Corrective jaw surgery later in life, in addition to the necessary procedures to open the nasal airway, may be required.


What Can Cause Mouth Breathing?

Whenever a child cannot breathe through the nose, a mouth breathing mode of respiration occurs.

One cause of nasal airway obstruction in the child is allergic rhinitis, where the nasal mucosa swells and blocks the flow of air. Most allergic responses are initiated by airborne particles, smoke, foods and pets.


Severe malocclusion

While there is a genetic inclination to develop allergies, research suggests that early treatment of allergic disease can alter the course of allergic symptoms for a lifetime.

The adenoids and tonsils, frequently the target of blame for airway obstruction, often are enlarged in response to infection of the nose and sinuses. Since allergy predisposes to infection, allergies should be controlled before the adenoids and tonsils are removed.

Thus untreated allergic children often are seen to have a nasal airway obstruction even after the adenoids and tonsils have been removed.

Other causes of reduced nasal respiration include asthmas, nasal polyps, foreign bodies, deviated nasal septa, unreduced fractures and congenital nasal deformities.

Treatment of nasal airway obstruction and mouth breathing should involve a multidisciplined approach. The trained dentist is uniquely qualified to monitor the growing face and may often be in the middle of a referral pattern involving otolaryngologist, allergists, pediatricians and other health care professionals.


Evaluate the facts

If a young, rapidly growing child has chronic untreated nasal obstruction and must breathe through his/her mouth all day and all night, then the normal muscular activity of the face and jaws will be altered.

Despite considerable interest in the problem among health care professionals, there is still no uniform opinion regarding the effects and treatment of a child with a mouth breathing habit. Regardless, the following facts should be carefully evaluated:

  1. Mouth breathing is abnormal.

  2. Mouth breathing can affect the entire system.

  3. Mouth breathing can particularly affect the facial muscles and bones of a growing child.

  4. Mouth breathing can cause facial deformities that are often too severe for orthodontics to correct. These individuals may require jaw surgery later in life.

The American Association of Orthodontists recommends a child’s first visit to the family dentist at age two and an orthodontic examination at age seven.

However, parents should be keenly aware that care of the developing face begins at birth, and any nasal airway problems should be addressed as soon as they are noticed. How your children breathe should not be taken for granted.


Source: This fine airway article was written by Dr. Stephen Sherman and originally appeared in the Parent’s Journal.


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