What causes crooked teeth? How to prevent it? Is it caused by genetic or environment? Studying past human skulls gives us great insight about crooked teeth, is it a natural phenomenon? when did it occur and why? Orthodontists prescribe to the idea that the cause is a mix of genetics and environment like most other diseases however we are treating it as entirely genetic problem while overwhelming evidence points to the environment.
Malocclusion is misalignment of jaws and/or teeth. It has become an endemic problem affecting 80% of civilized population.
In the modern world getting braces have become right of passage to growing up. But should this be accepted as normal?
An important distinction between cause and effect: orthodontists are treating the symptoms(the effect), it is openly admitted in the profession that they don’t know what actually causes malocclusion.
Isn’t it interesting…
- Humans are 1 species out of 5,400 other species of mammals and we’re the only ones that get crooked teeth
- we have been anatomical humans for 160,000 years out of which malocclusion has only begun to show in the mass population 200 years ago
- Our ancestors had 32 perfectly aligned teeth with 10 mm of space behind their wisdom teeth. There was no need for orthodontics!
- only 5% of ancestors had malocclusion (from obvious causes like trauma or illness), in modern population only 5% have correct occlusion
Evolution Theory & Genetic Theory
–Evolution theory: “Humans are evolving to have different jaws than ancestors, hence impacted wisdom teeth becoming normal”
–Genetic theory: there is too much outbreeding (too much contrast in gene pool) or the opposite too much inbreeding.
Believing that DNA is at the cause makes logical sense to us, since we see the similarities in our faces to our parents.
- but if the common theory of teeth crowding: “you inherited teeth too big from dad and jaws too small from mom” was true, how come we don’t see the opposite where the child inherits jaws too big and teeth too small and have gaps everywhere?
- a miniature Poodle can be mixed with a Great Dane (x100 larger) with clearly contrasting teeth and jaw size, but the off spring will have perfectly matching teeth and jaws
- At the turn of 19th century when the world went through massive changes with Industrial Revolution, malocclusion went on a sudden rise. This shift reflect change in environment not the gene pool.
- Inuit population were recognized as Canadian citizen and given social housing and food stamps. They moved into modern civilization, within 1-2 generation they had the same levels of malocclusion as rest of us (similar observations are made through out the world)
The gene theory can not explain the rapid rate at which malocclusion shows up, especially when pure bred populations get affected so quickly.
One theory of malocclusion is that we are missing certain vitamins in the modern diet that is impeding proper development. This seems plausible but hard evidence is lacking.
And few points that is difficult to explain:
- Animals don’t require special vitamins to get their straight teeth
- Anthropologist, Corruccini, found that malocclusion occurred 9x more in privileged Indian kids than their relative who were poor. Similarly, many population in third world countries with appalling, nutritionally deficient diet have better occlusion than civilized population.
- Humans had great occlusion for thousands of years as hunter & gatherers, it is not plausible to believe they all had access to these specific vitamins at all the different places & different times.
Masticatory Effort Theory
Because skulls and teeth are left behind, studying past skulls and comparing to present skulls have left us clues about the story of malocclusion and its connection to human’s masticatory efforts, which become difficult to be dismissed.
Below skulls were found in Japan.
- (left) 18,000 year old hunter gather skull – wide & square structure, heavy wear on teeth
- (middle) roughly 300 B.C. – skull beginning to lengthen, more oval shape, teeth not meeting as well, less wear on teeth. Beginning of heavy rice agriculture
- (right) Edo period1600-1800 – skull further lengthened, much less wear on teeth, much more civilized society, more sophisticated diet, foreign trade established
The face is lengthening at the same time wear of teeth is reducing, the main cause must be the shift in diet from hard to soft.
Muscular Dystrophy shows that weak muscles can lead to lengthening
With ultrasound they found that people with closer to 90 degree jaws had much thicker jaw muscles while individuals with more obtuse jaw angle had thinner jaw muscle. (it makes sense when you see that the jaw muscle attaches right at this angle)
masseter muscle runs top to bottom of the skull, could it’s strength manipulate the shape of the whole skull?
Bone is quite malleable to long term forces. Evidence suggests that bone is at the effect of the soft tissues.
Research showed that individuals with stronger biting force had wider Interpupillary distance. (or wide set eyes / wider face) As if the strong masseter muscle has crushed the whole skull making it shorter and wider.
Ancient Aboriginal with shorter, wider skull with much more forward jaws with pronounced cheekbone where the jaw muscle attaches. In animals, species with larger cheekbones have stronger biting power as there is increased surface area for more muscles to attach.
Muscle tone also affects resting posture. Strong jaw muscle keeps jaw shut, while weaker muscle tone lets the jaw hang open more often.
Monkey Experiments: a piece of plastic was placed on the roof of monkey’s mouth that made it uncomfortable for them to keep their mouth closed so they adopted open mouth posture, within a relatively short period the face lengthened and malocclusion developed. Another experiment in which the nose was plugged causing oral breathing lead to the same result.
Above shows that open mouth posture alone can cause lengthening and malocclusion.
Boy was allergic to pet gerbil he received as present, blocking his nose causing him to oral breath.
Leaving the mouth open for any extended period of time results in Cranial Dystrophy.
Jaw shut, and tongue on the roof is the support for the face.
Malocclusion is symptom of Cranial Dystrophy
Orthodontist, John Mew found that faces that are short is wide with plenty of space for great occlusion while faces that are longer is more narrow and prone to malocclusion. He saw that malocclusion was simply a symptom of a face that is lengthening. Other symptoms: unattractive appearance, throat & nose problem, breathing difficulties (snoring & sleep apnea), TMD, bad body posture.
From Hunter Gatherer to start of agriculture to modern human, there is one clear shift occurring: Cranial Dystrophy
Proper facial development which is horizontal (left) is becoming so rare in the modern world where everyone is heading south (right), that we no longer have proper reference anymore for what is the ideal? We see some that resemble our idea of ideals on magazines and movie screens but even within those “modern ideals”, true ideals are few and far between.
if malocclusion is a symptom of vertical growth, then facial beauty is consequence of horizontal growth.
Cranial Dystrophy Following Industrial Revolution
Drastic changes in lifestyle occurred after Industrial Revolution. People moved from farms to cities and got wage jobs and transitioned from home grown food to processed diet.
Humans have proclivity towards maximizing gains while minimizing effort. This naturally leads to refinement of diet towards more pleasurable food which is softer and higher calorie. Overtime dramatic reduction of masticatory effort per calorie.
Machines are able to process much of the fiber out from most food, ie: whole wheat to white flour. As well as introduction of freak foods like sugar that spike effortless calorie. It is highly concentrated, man made substance that was once expensive, reserved for the rich but became available to the masses with drastic reduction in price sometime in the 1950’s with advanced mass production machines.
Malocclusion was still uncommon 200-300 years ago, when people lived more natural lifestyle on farms. Out door activity leading to healthy appetite and wholesome foods containing fiber which meant healthy amount of chewing each day, and also less allergies compared to modern times.
How much more chewing will be required by a child to meet the same calorie intake of a chocolate bar by eating apples instead?
Every time sugar is put into a tea for example, there is that much less masticatory effort per calorie done for the day.
This explains why malocclusion occurred first in the wealthy class, going back all the way to the Romans. They had money to procure these pleasurable foods, soft and calorie dense. And why less privileged children have better occlusion as they are eating poor diet that are tougher, more fiber, more grit, and way less calories, which means they must chew several times more just to get enough calorie on board to survive.
Ancestors wore their teeth down to the root by the late age, today we don’t wear away even the cusps of teeth. There has been a drastic reduction in jaw usage.
on principle of use it or lose it, we are losing it. At the same time, drastic weakening of jaw muscle is leading to change in oral posture from closed to habitually open with disastrous consequences. There is quite dramatic changes taking place in skull structure which is accelerating within the last 50 years or so. As the face lengthens, the facial dimension gets reduced and teeth run out of space. As well as the fact that teeth sit in the balance between tongue and lips, when the mouth is habitually left open and tongue lowered, this balance is lost and the teeth will begin to shift.
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