What Is the Curve of Spee — And Why Dentists Rarely Talk About It
Share
There's a concept called the Curve of Spee that sits at the center of everything happening in your jaw, your skull, your spine, and your long-term health — and your dentist almost certainly has never mentioned it to you.
It's not because it's obscure. It's been in the anatomical literature for over 150 years, named after the German embryologist Ferdinand Graf von Spee who first described it in 1890. It shows up in dental textbooks. Orthodontists learn about it in school.
The problem isn't that they don't know what it is. The problem is that most of them don't understand what it means — and what happens to the rest of your body when you lose it.
What the Curve of Spee Actually Is
The Curve of Spee is the arc formed by the biting surfaces of your teeth when viewed from the side.
Start at your lower front teeth and trace a line back along the tops of the premolars and molars — in a healthy mouth, that line curves upward as it moves toward the back. The back molars sit higher than the front teeth in the arc. It's a gentle, continuous curve that mirrors the natural geometry of a healthy jaw and skull.
The simplest way to visualize it: imagine holding a sphere roughly the size of a large grapefruit and placing it against the side of your teeth. In a healthy mouth, the biting surfaces of the lower teeth would rest along the curvature of that sphere. The curve isn't arbitrary — it's the natural geometry the jaw and skull evolved around.
A flat occlusal plane — where the biting surfaces of all your teeth sit on roughly the same horizontal level from front to back — is a sign that this curve has been lost. And when the curve is lost, it's not just a dental finding. It's a structural finding with consequences that run through the entire system.
Why This Curve Matters So Much
Here's the thing most people don't grasp until they've spent serious time studying these biomechanics: the Curve of Spee isn't just a feature of healthy teeth. It's a reflection of whether the entire skull and spine are structurally sound.
The skull has approximately 29 moveable bones held together by fibrous joints and covered by a layer of soft tissue — fascia, connective tissue, skin — that maintains the whole system under tension. Think of this as an inflatable structure. When everything is working correctly, the system is inflated and properly tensioned. The bones are spaced correctly. The face has good definition. The spine sits properly beneath it.
The Curve of Spee is one of the primary indicators of whether that system is inflated or deflating. A healthy curve means the system is holding up. A flat curve means it isn't.
When the curve flattens — from grinding, from orthodontic treatment, from dental work that changed how the back teeth come together — the soft tissue covering the skull begins to lose tension. The skull starts to compress. The jaw drops into a lower position. The cervical spine compensates. The whole chain of structures running down from the skull starts to twist and collapse.
This is not theoretical. It's physics working on a biological system. And the downstream effects aren't subtle — they include chronic neck and shoulder tension, postural collapse, brain fog, poor sleep, facial asymmetry, and a whole range of health issues that most people never connect back to what happened in their mouth.
How I Learned This the Hard Way
My entire journey into these biomechanics started with what a dentist in Vietnam did to my occlusal plane in 2014.
I'd been wearing a dental splint that was working — one that happened to have a relatively flat surface and wasn't locking my bite. My neck and back tension, which had bothered me for over a decade, had largely disappeared within a couple months of wearing it.
Then I switched dentists. The new one told me my contacts needed adjusting and drilled down the cusps on several of my back molars to "correct" the bite. He flattened my occlusal plane.
Within a few months, everything fell apart. I couldn't sleep. I couldn't retain information. My whole body seemed to be aging in fast-forward. My vision worsened. I became a hermit. What had been a decade of chronic tension became something far more serious, and fast.
That grinding down of my back teeth — that flattening of the occlusal plane — destroyed what remained of my Curve of Spee. And once I understood what had happened, I spent years figuring out how to rebuild it.
My experiments with a tracking splint — a flat-surfaced lower splint where I'd bite on occlusal paper to map my contacts — made the relationship undeniable. Every time I wore a flat guard and let the system decompress, the curve improved. The contacts on the tracking splint showed that I was always grinding down the front of the splint as things got healthier — developing a curve where there had been flatness. And every time the curve improved, my spine, my cognitive function, and my face followed.
You don't change your structure without changing your Curve of Spee. I am certain of this after years of tracking it.
What Destroys the Curve of Spee
Understanding what damages the curve is important — because a lot of it is happening to a lot of people, and almost none of them know it.
Teeth grinding. This is the most common culprit. Years of grinding wear down the cusps — especially the back molars — and progressively flatten the occlusal plane. The frustrating part is that the grinding is often itself a symptom of the compression that comes with a flattening curve, creating a feedback loop that accelerates the problem.
Orthodontic treatment. Braces and aligners routinely flatten the Curve of Spee as part of the treatment process. In conventional orthodontics, a flat occlusal plane is often considered a treatment goal — it's called "leveling and aligning." The problem is that the curve isn't a cosmetic quirk of an untreated mouth. It's a structural feature that the jaw and skull depend on. Flattening it to make teeth look straighter in photos trades short-term cosmetic appearance for long-term structural deterioration.
Dental extractions. Removing teeth — especially molars — reduces the overall structural support in the arch and contributes to collapse of the occlusal plane over time. This is one of the reasons people who had premolar extractions as part of orthodontic treatment often notice their face changing in ways that only become fully apparent years later.
Dental work that changes molar height. Drilling down cusps to "adjust contacts," replacing molars with incorrectly sized crowns, or any intervention that changes the height relationship of the back teeth can flatten the curve. This is exactly what happened to me in 2014, and it's exactly what happened to others I've spoken to who trace the beginning of serious health decline to a dental appointment they thought was routine.
What Happens When You Rebuild It
The good news is that the Curve of Spee is restorable. And the mechanism for restoring it is simpler than most people expect.
By adding vertical height between the teeth — without locking the jaw into a fixed position — you give the soft tissue of the skull a chance to decompress. The doorstop effect I've written about extensively: the guard sits between the upper and lower teeth, prevents full closure, and stretches the soft tissue covering the skull. Night after night, the tissue responds. The skull begins to re-inflate. And as it does, the Curve of Spee improves.
You can track this. On a flat plane splint used as a tracking tool, the evidence is visible: as the system improves, the contacts shift. The curve develops. The heavy spots move from the back of the splint toward the front as the arc restores itself.
This is what a flat hard mouthguard like the RevivOne is doing during the hours you sleep. It's not just protecting your teeth. It's creating the conditions for the Curve of Spee to rebuild — and for the skull, the spine, and everything downstream to follow.
Why Your Dentist Doesn't Talk About This
A few honest reasons.
Most dentists are trained to look at the teeth in isolation — whether they're clean, whether the contacts are even, whether there's crowding or wear. The broader structural picture — how the occlusal plane relates to skull mechanics, spinal alignment, and systemic health — isn't part of standard dental training.
Orthodontists specifically are trained to create a flat occlusal plane as part of treatment. "Leveling and aligning" is a core orthodontic goal. The idea that this is structurally harmful is, in the context of mainstream dentistry, a fringe position — even though the anatomical evidence for the curve's functional importance has been sitting in the literature for over a century.
There's also an uncomfortable truth about incentives. The Curve of Spee can't be billed for, managed, or treated with a product that requires ongoing professional care. Explaining it thoroughly to patients would require dentists to call into question treatments they've been performing and recommending for decades.
So they don't talk about it. And patients pay the price without ever knowing what the real issue was.
The One Thing Worth Knowing
If you take one thing from this article, let it be this:
The state of your Curve of Spee is a better predictor of your structural health than almost anything else happening in your mouth. It's more important than whether your teeth are straight. More important than whether your bite "feels balanced." More important than the shape of your jaw.
A healthy curve means the system is working. A flat curve means it's been compromised — and things will keep compressing until the curve is restored.
A flat hard mouthguard that adds vertical height without locking the jaw is the most accessible, lowest-cost way to start rebuilding it. Not overnight. Not in a month. But consistently, night after night, in a process that compounds over time.
That's what the RevivOne is designed to do.
Start rebuilding your Curve of Spee at getreviv.com
RevivOne is an occlusal guard designed to help reduce bruxism (teeth grinding) and jaw tension during sleep. Individual results vary. The observations and community patterns described in this article reflect the founder's personal experience and reports from community members, and are not intended as medical advice.