 Hey everybody, Dr. O here, in this video we're going to focus on the teeth. So here you see the oral cavity and I'll show you the teeth and we'll talk about them individually. But the oral cavity, the entire oral cavity has some sort of function whether it's in the chewing or swallowing or these types of things. But primarily when you think about breaking your food down in your mouth, you think about your teeth. Now the tongue's primary job is to move food around to make sure that it is hitting the occlusal surfaces of your teeth. But the teeth are going to do most of the work. Let's go ahead and take a look at them. You do have two sets of teeth or dentition, your baby teeth or deciduous teeth or primary dentition, those are all the same thing, your first set of teeth, your baby teeth. There's going to be 20 of those and then those are going to fall out and be replaced by your secondary dentition, your adult teeth or your permanent teeth and there's 32 of them. Let's go ahead and take a look at them and talk about their unique functions. So of those 32 teeth, they're going to have eight incisors right there in the front, four on the top, four on the bottom. They're really good for biting. So yeah, I'll try to use a keyword for each type of teeth, but biting into food is going to be the primary job of your incisors. Next to them, you're going to have the cuspids or your canine teeth. So our canine teeth aren't real sharp fanged canine teeth, but they're still called canine teeth because they do have the pointy or cusp on them, which is where the name cuspid comes from. So there's four of those and they're really good at tearing into food, especially really tough or fleshy food. That's why carnivores have them. So your canines think about tearing into food, especially fleshy food. Then we're going to have, I usually call them the bicuspids, but you'll see them called the premolars as well. So the eight premolars or bicuspids, the keyword there is they like to mash your food up. So so far we've bit into and like clipped into our food. We've torn into more fleshy food. Now we're mashing up food here. And then lastly, you're going to have your 12 molars in the back. And they're really important. They kind of had these little pointy ends on the corners because their job is to crush your food up to make sure it's ready to be swallowed. So those are the different types of teeth and their basic function. So all of them work together. Obviously you take a bite of food. It's going to be moved around your mouth. It's going to be mashed up against the hard palate. It's going to be pressed between your cheek and your mouth all over the place. And your tongue's controlling where your food is sitting in your mouth, but it's the teeth that's doing the clipping and the biting and the tearing and the mashing and everything we just said there. All right. If you look at an individual tooth here, and I don't spend a bunch of time on this, but we would have covered back with the skeletal system that this individual tooth here is sitting in an alveolar process of either the maxilla, your upper jaw or the mandible, your lower jaw. And if you look at all of the alveolar processes together, that'd be called an alveolar arch. This is an example of a gomphosis joint, a tongue and groove joint. So this tooth is sitting inside your maxilla or your mandible. Different parts. The bone of the tooth is going to be the portion of the tooth that's outside of the gum line, the exposed portion. The neck of the tooth is going to be where your gingiva or your gums are. And the root of the tooth is going to be the portion of the tooth that's actually hidden or inside the socket created by the maxilla or the mandible there. So the two main parts of the tooth would be the crown, which is above the gum line, and the root, which would be below the gum line there. Let's see here. So inside you see that pulp cavity where the nerves and blood vessels are. If you get a cavity or a dental carry, you get some sort of damage to your tooth that exposes those nerves. That's why dental pain can be so excruciating, so unbelievably painful. But surrounding that pulp cavity, you're going to see dentin. So dentin is going to hopefully keep that pulp cavity encased. And then outside of dentin, you're going to have bone-like structures. So if you're below, if you're at the root there below the gum line, it's going to be called cementum, very tough bone-like material there on the outside. But more famous would be what's called the enamel. The enamel is the bone-like material that's on the outside of this dentin above the gum line. So the enamel is the tooth that you see. It's called the hardest substance in your body. And protecting your enamel is very important. So if you don't, so obviously flossing and brushing is not a dental health class, but these kind of things are critically important, mainly because of the relationship with your teeth and the microbes inside. So let's go and look at some of the things that can happen just to scare you a little bit, I guess. But so here you see, so like first when you see plaque. So we talk about plaque formation on your teeth. Plaque is actually a biofilm. So plaque is the microbes living in your mouth will form this thick coat to protect them and try to hide them from your immune system and brushing and these kind of things. If plaque is able to hide these organisms, especially strep organisms like streptococcus mutans, they're going to feed on the sugars that you eat and they're going to produce acidic byproducts. So the acidic byproducts of these bacteria will lead to tooth decay or dental caries. The tartar here you see right in the middle, that's going to be a plaque. If plaque is allowed to stay on your teeth, if you don't go to the dentist often enough for cleanings and you don't brush and floss properly, plaque can form this tartar. It actually calcifies. The plaque will mix with minerals in your saliva and form this really hard crust that needs to be removed. They scrape it off at the dentist, those kind of things. So that's what tartar is. We talked about dental caries and tooth decay. As far as protecting your teeth, clearly brushing and flossing and going to the dentist, these are all very important things. Fluoridated dental products can be helpful as well. What else? I mean obviously if you eat less sugar, right, if these bacteria are feeding on sugar, then the more sugar you consume, the more quickly this metabolism is going to occur inside your mouth. And then lastly, that is interesting. If you chew gum, you know, the four out of five dentists agree that you should be consuming sugar-free gum. And that's because the xylitol that's in many of your sugar-free gums is actually a biofilm disruptor. We talk about that more in microbiology. All right, so that is your oral cavity, your teeth, and then what an individual tooth looks like. I hope this helps. Have a wonderful day. Brush.