 Then a guy called Wool, Cole. And a guy called Cole here took monkeys, and he did a different thing. He basically disconnected the muscles, repositioned them so they were stretched further. I know poor animals. We do do this in science sometimes. It teaches it a lot. And what happened was it shortened the face. So you see, this was the lower border of the mandible pre-vis, to the experiment, ac mae'r bapwyr y ddaig yn preventing? Cymru'r bapwyr mae'n gweld... ..so'r bapwyr ystafell hwnna nes gael'r ddweud. Dwi'n digwydd y dyfodd o'r llwyffydd, mae'n dechrau. A nhw'n hefyd filed ydw i'r bobl yn dynion... ..o'r bobl yn dynion'n hefyd yn dechrau. Felly rydym yn Thankyou ac Panthafoedd. Yn ymwybodio'r bobl yn dynion dynion.. ..o cymryd gwirbwyng. Mae gael ddweud o ddim yn rhan o'r dweud, ond mae'n bwysig i'w blaidio. Mae'n bwysig i'w blaidio yn ysgrifennu, mae'n eich ddweud, mae'n leolau. Mae'n gweld bod yn cyflodd neu gweld. Dyn ni'n gweld bod yn cyflodd neu gweld, mae mae'n ymwneud bod yw'r mawr o'r ddaeth. Yn ymwneud bod yw'r mawr, mae'n ddweud ymlaen i'w gwybod, a mae'n ddweud i'w gwybod. Mae'n ddweud i'w pwysig o'r ddweud, ..that we're very nicely exhibiting for us here. He's gone from this to this. And in doing so he's completely affected... ...the pattern of his facial growth. I mean, he looks like a different person. Now, if I'm trying to try and give you two examples! Two examples with good facial growth, good horizontal facial growth... ...or we've got the vertical growth. And this is the problem I'm describing, is this vertical growth. Now this is an example here of the good horizontal facial growth. Oh... You don't have the same version of PowerPoint a I do! Ok, I'll have to describe for you. The face would normally move forwards Yes! and you get the tight muscles and the closed mouth posture restrict the facial growth. so the facial growth goes forwards Rydych chi'n gweithio y ddweud y bydd yng nghylch yn dweud a ddweud y bydd yn dweud, a y diolf yn gweithio ac mae diolf y ddweud. Ddiolf yn cyffinol, mae'r ddweud y diolf yn dweud. Dwi'n ddweud y ddweud wrth y bydd y bydd yn ddechrau. Mae'r ddiolf yn ddechrau gynhyrch. Dwi'n ddweud y bydd yn dweud y ddweud, ond rwy'n gweithio'r ddweud o'r ddweud o'r ddweud. It doesn't even matter how hard I try that, it's not going to happen, and that's quite important. Because if I fell over or I had a skiing accident or I just a running accident, that could severely damage my life and my airway is my life and that's an important thing not to happen. Now a graphic illustration of this is that these two mandibles are the same length. One of them is coming from a horizontal grower, this mandible here, and the other ones come from a vertical grower, this mandible here. And of course, in that increase in the vertical change, there's changed that shape of that mandible. And although they're the same length, the actual space for the teeth is shorter, is longer on the square mandible, than on the shallow mandible. And this explains a great deal why we're getting impacted wisdom teeth and we're getting crowding at the front of the jaw. Only a thousand years ago, all of the skulls dug up in several Danish experiments or study work, had every single wisdom tooth present working and in function in a time when you couldn't take these teeth out. So certainly our ancestors had a very different situation than we do and fairly recent ancestors and a fairly purebred population. Now, again we're not going to see this one running as well, now a guy called Markot noticed that it doesn't matter who you are, but almost all of us keep the point nasion just here and the point bagonian just here above each other. So if you have this change in facial shape that I'm describing, doesn't matter how much your face changes, but you'll move your head so the front of your face is perpendicular. I think this is probably because we're social animals and that's what we like to do. And that's described with this woman here. What she's done, she's moved her head. You see she's got, hang on, let's see if it's going to work properly. No, she's got a sloping forehead. Why's she got a sloping forehead? Very strange because it's not neanderthalic in any way. Because sloping forehead, because her face has melted down, cheekbones have disappeared, the nose looks larger because of it. And as that's melted down, she's just rotated her head upwards. Now she's rotated her head upwards, it makes the forehead look like it's sloping backwards. See people with big noses often have sloping foreheads. It's not a coincidence, it's the way they've grown. Now what I often describe this is I describe it as a bit like a waxwork model. Someone's got a little bit close to the fire and it's melted away. Now that's this increase in vertical growth. And it comes from the musculature and it comes from the tongue posture. Now we're going to ask, again when you look at something, you need to look at the epidemiology of it. It's part of making science is looking at the epidemiology. We know for something like sickle cell anemia. Sickle cell anemia started in two places in Africa and one place in India because it had an advantage in the sickle cell trait against malaria. It was passed on and you can see the spread of the populations around like contours on a map of the percentiles that have these particular feature within them. If we look at blood type here, blood type O within the population, it gives you an idea of the spread of populations, the spread of the genetics around the planet. And although you do see a pattern of types of malocclusion around the world, it's only tendencies, it's not an obvious thing. And also you think where was the first case, where did it come from? Well, it came in all races, in all members of those races, in all areas, roughly when we started becoming civilised. If you ask anthropologists and archaeologists, they say that happens when we become civilised. And about from the Neolithic period, 10,000 years ago when we got animals and crops and we got the great serial killers. And it's a little bit chicken egg. There's a definite interaction between the genes and the environment, but it's a cause and a predictor. The genes predict what type of malocclusion you'll get if the environment will cause it. For example, where are those kids growing? They're growing downwards. Where are we growing? The muscles have changed, their motor tone and their function, the tongue and the jaw has dropped. And that's what's happening. Here's an ancient skull on top of a normal modern skull. We don't have a lot of those ancient skulls, unfortunately. And I think that's part of the problem.