The Surprising Reason Why Human Teeth Are A Design Disaster - Cheddar Explains

you've probably had a cavity or braces and if you haven't you probably know someone who has cavities also known as tooth decay are the most common and pervasive chronic disease in the world nine out of 10 adults over the age of 20 have some degree of tooth decay and over 4 million people in the u.s have braces right now crooked and decaying teeth are so common that americans spend over 111 billion dollars a year trying to fix them and to be clear this is an almost uniquely human problem most animals are born with their pearly whites perfectly aligned even our distant hominem ancestors hadn't even an organized set of chompers so how did it get so bad for us [Music] the list of our teeth issues seems never ending first there's cavities or dental caries that happen when bacteria that live in our mouths feast on the sugars we eat and produce acids which corrode our teeth forming little holes we call cavities then there's the issue of our wisdom teeth seventy-five percent of people have wisdom teeth that don't have enough room to emerge properly causing swelling pain and infection and of course 9 out of 10 people have misaligned teeth what dentists call maloccluded to learn why we have the worst teeth ever we have to time travel back 400 million years ago to the cambrian era the first vertebraes jawless fishes were swimming around eating microbes and enjoying the relatively new sensation of being alive the descendants of these jawless fishes developed scaly head and tail armor made from tooth-like plates of calcium phosphate an interesting thing about conor dots is that we've discovered pretty much only their teeth because the rest of their body was soft tissue and doesn't fossilize very well so for a long time about 100 years paleontologists really only had the teeth and they were always sort of in search of what animal they belong to these plates had an outer surface a dentin sometimes covered by a harder mineralized cap and an interior pulp chamber housing blood vessels and nerves just like the teeth we have today most paleontologists think that these scales were eventually co-opted to form teeth even today's sharks have scales so similar to teeth that we lump them both into a category of structures called odontoeds teeth were a huge part of the early evolution of mammals because they're incredibly important for supporting warm bloodedness or endothermy endothermy required a ton of energy mammals burned 10 times more calories than reptiles of a similar size living in cooler climates and places with varying temperatures sustaining high travel speeds for long periods of time to maintain large territories stamina for foraging predator avoidance and parental care all require so much energy i'm exhausted just listing all of those things mammalian teeth couldn't skate by just tearing our food into non-chokeable pieces they had to get all the energy out of our food and to do that they had to chew while it might not seem like it at first glance chewing is a precise thing for proper chewing the top and bottom teeth need to align down to the millimeter herbivores have flat teeth for grinding plants their front teeth are also flat they don't need pointy incisors to latch on since their food isn't trying to escape all actually gorillas are vegetarians so these teeth in the front are not used for eating at all actually it's the teeth in the back that reveal how the gorillas process their food and what you see here are teeth that are very very well optimized for grinding and that's exactly what gorillas and other apes do with vegetation so they take leaves and other brush and they grind it carnivores have sharp scissor-like teeth for holding onto prey and tearing meat into pieces which are normally swallowed in whole chunks omnivores like us have a combination of sharp front teeth and molars for grinding and here is where we start to see the problem with human teeth humans have 32 teeth way fewer than most animal species and relatively small jaws this means there's a very small margin for error in the developmental stages that's a big problem because our teeth aren't genetically stable a term that means we have random teeth missing sometimes of uh human history in terms of our anthropological history um our mouth uh was much more healthy than it is now and things like overbites which are sometimes called malocclusions misaligned teeth and even cavities were actually not a big problem in our in our ancient past this is a problem that doesn't affect other mammals but the biggest problem with our teeth isn't actually our teeth let's take another little time travel trip back to the 1920s famous australian orthodontist tick beck was researching aboriginal peoples who were living traditional lifestyles when he saw that all of them had perfect dental arches their front teeth were straight their wisdom teeth were perfectly functional he hypothesized that because their diets included more abrasive food their teeth wore down more because their teeth were smaller all of the teeth could fit perfectly into the pallets beck was on the right track but he got one key part wrong in 2004 harvard evolutionary biologist daniel lieberman conducted a study on hyraxes where he fed one group of young growing critters soft cooked foods and the other tough raw foods he found that higher chewing strains resulted in more growth in the bone that anchors the teeth lieberman proved that the ultimate length of the jaw depends on the chewing stress during childhood so it's not our teeth that are too big for our mouths it's our jaws that are too small for millennia human mouths were dealing with bad teeth but not the level of malocclusion that we see today lieberman found that we can blame the industrial revolution for our painful crowded palates with the industrial revolution came more processed sugary foods instead of the tough grains and meats that we ate before and the reason why we have that problem is because we process our food before we put it in our mouth we cook our food we slice and dice our food and we eat softer foods easier to digest food without the stimulation from the tougher foods our teeth became crowded at the front and impacted at the rear so if you look at these two skulls here you can see some of the differences in how we eat in the food we eat are reflected in our skulls so this is a species known as australopithecus afarensis and if you look and you open up her mouth and you can see wide and flat those molars are and they don't really look like armors at all there's almost no depth to them and no crests partially that's because they've been been worn down over years and years of chewing but also what it indicates is that they were accustomed to eating very tough very hard vegetation and another major difference that you'll see in this skull is how big the space is for the jaw muscles that come up here and attached to the top of the skull and down here this individual is well adapted for tough foods with very low caloric intake but if you look at modern humans everything about the jaw is reduced this the mouth the teeth the space in general is much smaller the jaw itself is much simpler and smaller and you can see the space where the jaw muscle goes is much reduced as well plus the industrial revolution brought with it the sugary acidic processed foods that cause rampant cavities while there are certainly cavities in the fossil record that prove historical people did have dental caries these fossils are mainly in places with lots of fruit or honey and even then they're pretty rare basically our teeth are not tough enough to stand up to the sugar and acids we eat but our jaws aren't tough enough to stand up to our teeth it's an engineering catch-22 everything's falling apart and at this rate it's only going to get worse scientists say we should be taking cues from people who live traditional lifestyles since typically they have way better teeth than the rest of us who were fed gerber mush feeding kids tough raw foods will stimulate their jaw bones to grow more and better fit their teeth and the lack of sugar will cause less cavities unfortunately for the rest of us who've already stopped growing there's nothing we can do to fix the design disaster inside our mouths do you have lots of cavities or crooked teeth let us know in the comments make sure you click subscribe and don't forget to ring the bell for post notifications we'll see you next time

Channel: Cheddar

Views: 1,976,076

Rating: 4.9006457 out of 5

Keywords: Cheddar, cheddar explores, explainer, cheddar explains, teeth, human teeth, dentist, dentistry, mouth, human mouth, cavity, cavities, wisdom teeth, wisdom teeth removal, evolution, biology, design disaster, fillings, types of teeth, human body, rotten teeth only human, permanent teeth, structure of teeth, how many teeth do humans have, teeth functions, rotten teeth, humans, only human, arrangement of teeth, teeth types, names of teeth

Id: PzYLSPY5yFw

Length: 9min 32sec (572 seconds)

Published: Wed Sep 16 2020

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