Orthodontics and the Airway: Is there really no evidence?

Today we are following up on the debate about the airway.  This post is by Padhraig Fleming and I spotted it on the excellent Orthodontic Fundamentals Facebook Group and Ortho Reads Instagram. I thought that I should share this on my blog.  It is a great summary of useful research.

Introduction

Many of you who peruse Orthodontic Facebook groups will be aware of a recent debate surrounding the airway chaired by Kyle Fagala. This has become an increasingly emotive topic. I must admit that I sit firmly on one side of this fence having read and assimilated the evidence (something that I firmly believe should be a prerequisite to any claims made in either direction). Kevin O’Brien did a typically clear and incisive summary of the discussion on his Blog last week.

Lack of evidence?

I note that one thing that those on opposing sides of the ‘aisle’ could agree upon was a lack of evidence. Without wishing to present a contrarian view, I think this is sometimes a slightly lazy assumption that we make. As we know, evidence is often inaccessible for a range of reasons. Many of you will know that we have tried to remedy this by producing a simple Instagram resource involving potted summaries either of high-quality research or pivotal topics (@OrthoReads) driven by the inimitable Chong Jun Ai. We have been fortunate that Carlos Flores-Mir agreed to summarise four papers on the airway this month. I have summarised these below and would encourage you to have a read of these.

Paper 1

The first paper is an excellent crossover clinical trial – the highest possible level of evidence which suggests that even in children both with tonsillar enlargement and a narrow palate removing the adenoids/tonsils first is the most effective way to reduce obstructive sleep apnea events and improve oxygenation. Any benefit of palatal expansion was marginal to none even in this cohort with transverse maxillary constriction.  Kevin has previously posted about this trial.

In this study, a group of 32 non-obese children (mean age 8.8 years) with a Class I skeletal relationship but significant tonsil enlargement (Grade III/IV) and maxillary constriction were treated in a crossover randomized trial with adenotonsillectomy (AT) and palatal expansion (PE). One group received AT first, while the other had PE first. If a child still had OSA (AHI > 1) after 6 months, they crossed over to receive the second treatment. The primary outcomes were changes in the Apnea-Hypopnea Index (AHI) and Minimum Oxygen Saturation (MinSaO2).

Most of the improvement in breathing (AHI reduction) and oxygen levels (MinSaO2) was attributable to AT rather than the PE. Improvements in the lowest oxygen levels during sleep were primarily driven by the initial severity of the condition. Those receiving AT first showed much better overall outcomes. The combination of initial AHI severity and AT as the first intervention explained 95% of AHI improvement. PE had only a marginal effect on sleep apnea parameters when adjusted for other factors. The degree of improvement in AHI or oxygen levels when used as a standalone or follow-up treatment was not comparable to the impact of AT.

Key clinical take-home message: If a child has both enlarged adenoids/tonsils and a narrow palate, removing the adenoids/tonsils first is the most effective way to reduce obstructive sleep apnea events and improve oxygenation.

Paper 2:

Ther next paper challenges myopic ‘magic bullet’ approaches to OSA management (such as the putative benefits of orthodontic treatments). The authors argue for a transition from the “one-size-fits-all” application of Continuous Positive Airway Pressure (CPAP) toward a patient-specific approach for Obstructive Sleep Apnea (OSA). OSA is a chronic, systemic, inflammatory, heterogeneous disorder driven by diverse physiological mechanisms.

They propose three non-anatomical (ineffective upper-airway muscle responsiveness, a low arousal threshold, and high loop gain (instability in ventilatory control)) and one anatomical (upper airway narrowness) factor involved in adult OSA. The applicability of this concept in children is unknown. Any given patient has one or more of these factors. By identifying these specific underlying causes, clinicians can move beyond CPAP to multiple consecutive or simultaneous targeted therapies such as oral appliances, upper-airway surgery, oxygen therapy, or pharmacotherapy.

Take-home message: Integrating subtype profiling into clinical practice is essential to successful OSA management.

Paper 3:

This is a clinical practice guideline from the American Thoracic Society (2024).

The authors explore the lack of consensus on the management of persistent OSA in children following adenotonsillectomy (AT) (the accepted first line treatment). This accounts for 40% of those having AT for OSA. Recognizing the limitations of a universal approach, the multidisciplinary panel provided evidence-based recommendations for six targeted interventions, one of which falls within dentists’ scope of practice. The guideline suggests that children with persistent OSA and site-specific airway obstructions concomitant to relevant craniofacial features may be considered candidates for dento-facial orthopedic treatment.

Take-home message: Although dentists may play a role in managing children with OSA, due to very low evidence certainty, the authors emphasize shared decision-making to optimize interdisciplinary pediatric outcomes.

Paper 4:

The final article selected by Carlos Flores-Mir is a meta-analysis evaluating the diagnostic accuracy of questionnaires and clinical examinations for pediatric sleep-disordered breathing (SDB) compared to the gold standard, polysomnography (PSG). This is an important question given the challenges of diagnosing genuine OSA.

Most clinical tools lack sufficient evidence to replace PSG lacking both diagnostic sensitivity and specificity. Only one tool (the Pediatric Sleep Questionnaire, or PSQ) showed diagnostic accuracy high enough to be considered acceptable as a screening tool.

Take-home message: While dentists may be well placed to identify anatomical risk factors, the use of validated tools, such as the PSQ, is essential. Specifically, these may help for triage and to make appropriate referrals. It is important to not simply assume that a child has OSA based on specific craniofacial characteristics or breathing pattern. Identifying high-risk children through these screenings enables more efficient prioritization of limited PSG resources within the health system as part of an interdisciplinary approach

We hope that you find this information useful.