In this presentation Dr. William Hang, an orthodontist, argues that modern orthodontic practice must adopt an airway‑centric paradigm. He begins by showing a photograph of a patient with a narrow dental arch and predicts sleep apnea, a suspicion later confirmed by a New York Times article. Citing leading sleep‑medicine experts (John Remord) and evolutionary anthropologists (Daniel Lieberman), he explains that retruded maxillary and mandibular positions—common in industrialized societies—cause the soft palate and tongue to fall back, narrowing the pharyngeal airway and precipitating obstructive sleep apnea (OSA). He compares contemporary cephalometric analyses (Steiner, McNamara) with a Paleolithic norm (John Mew) to illustrate how forward jaw positioning would enlarge the airway. Using lateral head X‑rays, he demonstrates that airway cross‑sectional areas below 52 mm² indicate high OSA risk, referencing David Hatcher’s thresholds. He cites Michael Gelb’s “Airway‑Centric TMJ Philosophy,” which places the airway as the primary factor, followed by the joint/muscle, and finally occlusion. Hang presents case studies: a child with a narrow airway and high OSA risk, and a young adult whose orthodontic treatment without addressing airway resulted in persistent mouth‑breathing and OSA, despite CPAP therapy that, per a 2016 NEJM study, offers no cardiovascular benefit. The talk concludes that dentists routinely encounter patients whose health depends on airway‑focused assessment and treatment, and that fixing the airway is prerequisite to successful orthodontic outcomes.
Chapters
Hello, my name is Dr. William Hang, an orthodontist from Agoura Hills, California. Here's a nice-looking family with Fabiola, the wife, and the mother. Unfortunately, Fabiola's not going to be home tonight, or any other night, because she was in this train station in Hoboken, New Jersey, when this train came through, driven by this gentleman. Now, when I looked at this picture of Thomas Gallagher, I saw a very narrow dental arch, with the teeth set far back in his face, and I said to myself, this person has sleep apnea. My suspicion was confirmed when the New York Times published this article in November of 2016. And you say, that's unusual and uncommon, but no, it really isn't. John Remords, a Harvard-trained physician, one of the most famous sleep physicians in the world, states that sleep apnea will become the most common chronic disease in all industrialized countries. He further states that a structural narrowing of the pharynx plays a critical role in most, if not all, cases of sleep apnea. Finally, he states that OSA would not exist if the jaws were placed properly forward in the face. What we have in our society is faces that aren't coming forward the way they used to. It's not uncommon now for both of our upper jaws to be back substantially. The upper jaw can fall back, the lower The lower jaw can fall back. As that happens, the soft palate and tongue fall back, and this causes an airway obstruction back in the back of the pharynx where the soft palate and the tongue meet. Many of us look like this. Further evidence of this comes from Daniel Lieberman, who teaches anthropology at Harvard University. If you read his book on the evolution of the human head, you'll find that we have our jaws back substantially from those of our ancestors. Further evidence from this, or of this, comes from a book by John Mew. And he, here he has a proposed Paleolithic norm. The red line here is a Steiner analysis, which is something that's used in orthodontics. It shows what the ideal position of the maxilla might be. Here, the blue line shows the McNamara analysis, also commonly used in orthodontics today, shows where the maxilla might be. But finally, the green line shows where the maxilla might be in a Paleolithic norm. When you think of the significance of this, if our jaws were forward like this in the Paleolithic case, the soft palate would be forward, and the tongue would be forward as well. Here we see a child today who doesn't look that different than any other child. We have the Bolton norm superimposed on her face, and you can see how far back from a more ideal profile she is. But again, she's very common. Kids like this are quite common in schools throughout all industrialized countries. This is her lateral head x-ray, which shows a minimal cross-section of 65.2 square millimeters. If we now go to the refereed literature and look at David Hatcher's article and talk about the likelihood of someone having sleep apnea, he says that anyone with less than a 52 square millimeter cross-section— cross-section is at a high risk for sleep apnea. Someone with 52 to 110 is at moderate risk, and above 110, there's a low probability. The bottom line here is that girl has a high probability of having sleep apnea. Dr. Michael Gelb published a very important article several years ago in the California Dental Association Journal entitled Airway-Centric TMJ Philosophy. What he said was that the airway governs our ability to breathe and to achieve a restful, oxygenated, restorative night's sleep, as well as to perform optimally during the day. He further states that the teeth are the last piece of the airway-centric paradigm. The airway is the first, then the joint and muscle, and lastly the occlusion. The bottom line is, essentially what he's saying is, if you don't fix the airway, nothing else gets fixed. He and I then collaborated on a further article published in Cranio earlier this year. The title of that is Airway-Centric TMJ Philosophy: Airway Orthodontics Ushers in the Post-Retraction World of Orthodontics. I invite you to read this article to learn more. Let's take this information and look at a young man here who's proposed to have 4 bicuspid teeth removed. I happened to not remove his teeth. He came to me for a second opinion. We treated him without removing teeth. And we referred him for myofunctional therapy and breathing exercises in hopes that he would become a nasal breather and have his face grow forward. We delivered and straightened his teeth for him, but that's not the point. He's still a mouth breather, and his face fell down and back as a consequence of that. When he was finished with treatment, this is what his lateral head x-ray looked like, and he had an OSA diagnosis as a child in his mid-teenage years. Well, you say, no problem, he can wear a CPAP machine for the rest of his life and have a normal life. Unfortunately, that's not really the case. Even if he did wear the CPAP machine for the rest of his life, this study from the New England Journal of Medicine, August of 2016, states that there is no cardiovascular benefit of decreasing his chance of heart attack or stroke. But the important thing for you to note is every dentist has patients like this in their practice who need help.
