Thursday, May 18, 2017

Airway Obstruction and the Developing Dentition

Airway Obstruction and the Developing Dentition


There has been research around for years demonstrating that soft-tissue airway obstruction in a developing child leads to under-development of their upper jaw and constriction of dental arches; this in turn leads to crowding and many times a backward shift of their lower jaw.  The obstruction can be from chronic inflammation, swollen tonsils and adenoids, adverse tongue posturing or just anatomical thick tissue. If severe enough, it can lead us to recommend removal of permanent teeth or even surgery to re-position one or both jaws. We are also seeing that over time, this constriction affects the tongue space and can ultimately lead to Chronic Snoring and Sleep Apnea.

As a practicing Board Certified Orthodontist, I have treated thousands of patients with varying malocclusions that could be traced back partially if not wholly to airway obstructions.  Recently however there is a trend in our medical community to address these airway obstructions early to reduce the prevalence of Sleep Apnea and improve the long-term health of young patients before the symptoms of the airway restriction become severe.  Several local ENT’s in my community have become very proactive and I believe the research is continuing to demonstrate early removal of soft tissue obstructions in the nasal airway is absolutely warranted and helps in overall development and later quality of life.

Anatomy of the Nasal Airway with computerized imaging of airway space.

What we are really seeing in the literature is a merging of medicine and dental; perhaps something that is less common than it should be but nonetheless this sharing of data is now helping educate providers and push for better patient care and more successful outcomes.  From my practice, experience shows that by the time a patient sees the Orthodontist by General Dental referral, much of the damage is already done.  That is because most dentists gauge the need for braces by the crowding of the teeth and they tend to want to wait until most or all baby teeth are lost (which is entirely too late for more severe problems).  In these now adolescent cases, we use traditional braces (with or without expansion/removal of permanent teeth/surgical repositioning) to undo what we can and work to establish a new arch form with alignment of teeth while providing the best esthetics and function possible.  

“… experience shows that by the time a patient sees the Orthodontist by General Dental referral, much of the damage is already done.”

This adolescent was referred only after once all permanent teeth erupted; patient had a history of breathing problems and chronic airway obstruction that went untreated.

Following extensive Orthodontic treatment including Rapid Palatal (Maxillary) Expansion and removal of the upper right 2nd bicuspid; although the teeth are corrected and arches restored, stability will never be possible without long-term nightly retainer wear; following treatment, the patient was referred to an ENT for removal of excessive soft tissue for added stability.

Correcting a narrow maxilla or a smaller (retrusive) lower jaw due to an airway issue can be time consuming and expensive to correct later in life; stability is sometimes based not only on early intervention and good dental correction but also on alleviating any airway construction before or after the orthodontic correction.  Patients and parents of patients should understand that the development of the dental arches are usually only a reflection of the forces in the mouth; whatever causes a severe malocclusion will still be affecting the teeth following the correction.  Therefore it is important to consider the airways when determining if a correction can be maintained without long-term appliances/retainers.
At 7 years old, this young patient was identified as having large tonsils and an obstructed airway with under-developed upper jaw and retrusive lower jaw.

Following expansion of her upper  jaw, you can see the lower jaw has come forward; patient reports improved breathing and parents report correction of snoring.

At this point, patient is referred to an ENT for possible removal of tonsils and will be monitor as we await the remaining permanent teeth. 
For younger patients, an Orthodontist can identify the early signs of damage from an airway obstruction
and they can take records to confirm and quantify such narrowing in the airways.  If seen early enough, the effects of the airway obstruction can easily be corrected by expanding the upper jaw and freeing the lower jaw to come forward as well as referring the patient to a knowledgeable ENT for closer evaluation and possible removal of soft tissue.  Along with expansion, the Orthodontist may even choose to set upper front teeth (which erupt around age 6 to 8) into an ideal arch form while clearing a path and opening space for future eruption of commonly impacted teeth due to this problem.  We know from the literature and from experience that many impacted canines that would require surgical exposure can be prevented by simply restoring a narrow upper arch with a fixed (not removable) palatal expander.
Consider the following case with a severely impacted and transposed tooth.  Already late getting to us, it took expansion with limited braces in the early mixed dentition to correct the impaction and save the adjacent tooth from more damage.
Note the narrow upper arch secondary to chronic airway Obstruction and Allergies.
Panograph X-Ray shows the impaction of the canine (on the upper left side in the film)
which is erupting on the wrong side of the adjacent lateral incisor.  The following films
show the sequential movements to correct the impacted and transposed canine.

Review of sequential X-Rays shows the correction of the impacted cuspid following expansion and opening space for the blocked out teeth; the photograph shows the new smile as we now await the remaining teeth.  Airways have n=been increased from the process and we expect a stable long-term correction.
In a Februrary 2013 study published in the Journal of the American Association of Orthodontics (AJODO) ( ) entitled Tongue posture improvement and pharyngeal airway enlargement as secondary effects of rapid maxillary expansion: A cone-beam computed tomography study, investigators using computer tomography imaging on patients treated with palatal expansion measured the before and after airways and tongue posturing known to affect development and contribute to sleep apnea.
In this study, researchers pointed out that  Rapid maxillary expansion (RME) is known to improve nasal airway ventilation. Recent evidence suggests that RME is an effective treatment for obstructive sleep apnea in children with maxillary constriction.”
  Yellow arrows show the nasal airway space in four patients each with varying
amounts of resistance from soft tissue.

This study wanted to confirm these findings but also investigate the effects of Expansion on tongue position which have also been shown to cause sleep apnea.
In their conclusion, the authors stated that In children with nasal obstruction, RME not only reduces nasal obstruction but also raises tongue posture and enlarges the pharyngeal airway.” 

Yellow arrows show the varying size of tonsils and how they affect the airway space
in five different patients.

In other words, expansion opened air ways and improved tongue posturing in children.  Of course it also increases the arch length and regains space for future teeth thereby reducing crowding and risks of impactions.

A more recent study published this month in the AJODO, ( was undertaken to clarify the relationships between upper airway factors (nasal resistance, adenoids, tonsils and tongue posture) and certain facial patterns seen when treating patients with Orthodontics, specifically patients with small lower jaws (Class II) v. those with excessive growth of the lower jaw or underbite tendencies (Class III).  The findings revealed that the relationship of upper airway factors are different between different facial types.  The data suggested that patients with small lower jaws (Class II) had significantly more nasal obstruction/resistance and that decreased width of the upper jaw measured at the molars related to an increase in nasal airway resistance/obstruction and a less favorable tongue position.

Imaging showing molar widths, measured and compared to obstructive airways.
Combining the results of these two papers, Orthodontists can now show definitively that not only does a narrow upper jaw cause crowding and increased risks of impaction of teeth, but it also is correlated with reduced airflow, poor tongue posturing and an increased risk of sleep apnea.
What does this mean to parents?
First, it means all kids should be screened early by someone who is knowledgeable (Certified Orthodontist) and can see the signs of airway obstructions before problems become too severe; General Dentists are not trained to specifically identify this problem in developing children.
Second, Orthodontists must not only treat the symptoms of airway obstructions but they should also include their ENT colleagues in consultation to determine if soft tissue removal may be necessary either before or after palatal expansion.
Third, expansion is not just about the teeth.  If an upper jaw is narrow, it can lead to a smaller lower jaw, it can lead to further airway resistance and can even contribute to Sleep Apnea later in life. Expansion, when necessary, increases airway space and improves airflow in children.
In summary, only an expert in development (i.e. a Certified Orthodontist) is going to be able to determine when expansion may be necessary for restoring restricted airways.  Even without crossbite, an upper jaw can be significantly narrow as the lower jaw is pushed backward or the lower teeth fold inward to stay within the upper jaw arch form.  Waiting on a referral from someone who is not fully trained or experienced can lead to severe crowding, impactions and even Sleep Apnea.

If you have questions or comments concerning this or any orthodontic question, please feel free to make a complimentary new-patient appointment at either my Steiner Ranch location or my North-central Austin location on West 35th street and MoPac.


Dr. James R. Waters is a 1996 graduate from UTHSC Dental School in San Antonio, 1997 graduate of Advanced Dentistry from the UNMC in Nebraska and the 2001 Valedictorian graduate from the prestigious Saint Louis University Orthodontic Program receiving the J.P. Marshall award for clinical excellence in 2001.  He holds a Bachelor’s Degree in Science, Doctorate in Dental Surgery, a post-doctorate certificate in Advanced Dentistry, post-doctorate Degree in Orthodontics & Dentofacial Orthopedics and a Master of Science Degree in Orthodontics and is a Diplomate of the American Board of Orthodontics.  Dr. Waters and his wife of 21 years live in Austin, TX with their 4 children where he has a thriving, multi-faceted Specialist practice with locations in Steiner Ranch and North-Central Austin.  You can learn more about Dr. Waters at 




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