Dental Space
Why crowded teeth are a symptom of insufficient jaw growth — not a cosmetic problem to be fixed with extractions.
Observation
“Are the adult teeth coming in "crowded"? Is the palate narrow or the smile "tight"?”
Impact
Crooked teeth are a symptom, not the disease. They signal that the jaw didn't grow forward enough to house the human "32-tooth blueprint." The face is literally losing its space.
Source: Kahn et al., BioScience, 2020
Evidence & Quick Guides
6 resourcesThe Jaw Epidemic: Recognition, Origins, Cures, and Prevention
Researchers from Stanford make a compelling case in this paper: human jaws are shrinking, and it's not because of our genes. The change has happened far too quickly — over centuries, not millennia — to be driven by evolution. Something about how we live is causing it. The culprits they identify are surprisingly everyday: soft, processed diets that don't require much chewing, bottle-feeding instead of breastfeeding, and chronic mouth breathing. All of these reduce the physical forces that help a child's jaw grow to its full size. Humans are designed to have room for 32 teeth. Most of us don't. The consequences aren't just cosmetic. A jaw that's too small means crowded teeth, impacted wisdom teeth, and a narrower airway — all connected, all stemming from the same problem. The good news is that the authors believe early intervention — helping children develop proper tongue posture, nasal breathing, and chewing habits — could prevent much of this epidemic before it starts.
Rapid Maxillary Expansion as Treatment for Resistant Otitis Media with Effusion
Any parent who has dealt with chronic ear infections knows the drill: antibiotics, then more antibiotics, then the ENT suggests ear tubes. But this study tried something different — widening the palate instead. The children in the study all had two things in common: a narrow upper jaw and persistent fluid behind the eardrums that wouldn't go away. At the start, 73% of their ears weren't draining properly. After having their palate expanded with a dental device, nearly 70% of those ears recovered normal function — without surgery, without tubes. The connection? A narrow jaw affects the shape of the tubes that drain the middle ear. When you widen the jaw, you restore the geometry those tubes need to work properly. The researchers went as far as recommending palatal expansion as a first-line treatment before ear tubes for children with narrow jaws — a recommendation that could spare many children an unnecessary surgery.
The Effect of Teeth Extraction for Orthodontic Treatment on the Upper Airway
When an orthodontist pulls teeth to make room for the rest to line up, what happens to the airway behind those teeth? This review looked at seven studies to find out. The answer depends on why the teeth were extracted. In children whose teeth stuck out significantly, pulling four premolars and pushing the remaining teeth back narrowed the airway. That makes intuitive sense — moving teeth backward pushes the tongue backward too, leaving less room for air to flow. But in children with simple crowding (teeth that are crooked but don't stick out), extractions actually increased airway space, because the remaining teeth shifted in a way that gave the tongue more room. The honest takeaway: we don't yet know for sure whether these changes actually affect a child's breathing in practice. None of the studies measured real breathing function. But the anatomical concern is real, and it's a question every parent should feel comfortable asking their orthodontist: "Will this treatment affect my child's airway?"
Effects of Mouth Breathing on Facial Skeletal Development in Children
Researchers reviewed 10 studies comparing the faces of children who breathe through their mouths to those who breathe through their noses. The differences were consistent and significant. Children who mouth-breathe tend to develop longer, narrower faces — sometimes called "long face syndrome." Their jaws grow downward and backward instead of forward, their upper teeth push outward, and their airways get narrower. It creates a vicious cycle: the narrow airway makes mouth breathing worse, which makes the face grow even more in the wrong direction. This matters because it shows that mouth breathing in childhood isn't just a habit — it physically changes the shape of a child's face. The earlier it's identified and addressed, the better the chance of guiding the face back toward healthy development. Left alone, these changes become permanent.
Paediatric Maxillary Expansion and Nasal Breathing: A Systematic Review
This review looked at 12 studies involving over 300 children who had their palate widened using an expander — a dental device that gradually pushes the upper jaw wider. The question was simple: does widening the palate help a child breathe through their nose? The answer was unanimous. Every single study found that children breathed better through their nose after palatal expansion. Air resistance dropped, and airflow increased by a meaningful amount. Why does this work? Because the roof of the mouth is also the floor of the nose. When you widen the palate, you're physically opening up the nasal passages at the same time. It's one of the clearest examples of how dental treatment and breathing are connected — and why treating the structure of the face can solve problems that nasal sprays and allergy medications never will.
Does Ankyloglossia Surgery Promote Normal Facial Development?
"Tongue-tie" is when the strip of tissue under a baby's tongue is too short or tight, restricting the tongue's movement. Most parents hear about it in the context of breastfeeding difficulties. But this review of 7 studies and over 1,400 people reveals a bigger picture: tongue-tie can affect how the entire face develops. Children with tongue-tie consistently showed narrower jaws — both top and bottom — compared to children without it. They were also more likely to have bite problems and crowded lower teeth. The reason comes down to physics. The tongue is supposed to rest against the roof of the mouth, and that gentle upward pressure helps the palate grow wide and flat. A tied tongue can't get into position, so the palate stays narrow and high — leading to a cascade of problems with breathing, dental alignment, and speech. About 8% of babies are born with tongue-tie. The implication is clear: early assessment isn't just about feeding — it's about giving the face the best chance to grow properly during the years when it matters most.
The Difficult Question
Why do we pull healthy teeth out to "fit" a small jaw, rather than helping the jaw grow to fit the teeth?