hello today we're going to be talking about basic vocabulary that we use to describe Dental Anatomy that way next time when we talk about individual teeth um we know what words or terms to use describe the teeth and so today we're going to go over very quickly tooth numbering and surfaces then we're going to divide teeth into thirds and with those thirds we're going to be able to describe contact points and braur and Heights of Contours so I don't want to dwell on tooth ning Services too much because this was covered in oral physiology but I'm just going to go over real quick um as a quick recap so permanent human dentation has 32 teeth um you can have 16 in the Maxa and 16 in the mandible and it's divided into four quadrants with eight teeth in each quadrant and so what the universal numbering system is you get each tooth gets one number um you're going to start on the upper left right here is number one it's going to go over to 16 and then number 17 for the lower left over to lower right 32 and so for people who aren't used to the universal numbering system I think the easiest way to remember it is to just first commit to memory um the first and the last tooth in each quadrant so if you start 1 and 16 are going to be the first and the last tooth and then your centrals here are going to be eight and nine because you have eight teeth in each quadrant right and if you move on to the mandible first and last tooth it's going to be 32 and 17 and then the mandibular Cal Cals going to be 24 and 25 so now you already covered up a lot of ground area now the only problem is if I were to ask you what is the number for the upper left second premolar this tooth right here is kind of far away from number nine and it's kind of far away from 16 too so when you're not used to it and then you're on the spot it's difficult to quickly calculate what number that is so it's also good to remember what the Kines are that's going to be six 11 22 and 27 so now if I ask you what's the number for the upper left second premolar boom it's two away from Room 11 you know it's 13 so until you get used to U until it's second nature what um tooth belongs to one number um just remembering these numbers will give you a quick way to calculate um the number that you need for the tooth so moving on to surfaces when people talk about in approximal um surfaces or the proximal surfaces they're talking about the misal and the distal contacts or the surfaces sorry and meal refers to the surface that's closest to the midline so for number 13 that be right here this will be the meal surface CU it's closest to the midline as opposed to the distal which is a Surface that's further away from the midline and that's going to be right here that's going to be your distal uh next we're going to have the Buckle or facial and also lingual and the palal so buckle refers to the buxin nator so it's a surface that's closest to the cheek and that refers to posterior teeth so if I were talk about 15 right here the Buckle surface is going to be right here and facial is the same thing except it's for anterior teeth and then lingual and pal so lingual refers to the surface as closest to the tongue um so and it's for mandibular teeth whereas paleto is for the pallet and it's going to be for Max teeth but it's essentially the same thing or analogous to each other and so for number 15 the P of surface would be right here and then lastly we have the um biting surfaces so that's going to be the accusal or the incisal surface and so clusel refers to the Bing surface for posterior tee so that's going to be this right here and then for anterior teeth it's going to be the incisal surfaces so that's going to be this right over here so that's going to be tooth norming and surfaces so teeth are divided into thirds that way when we start talking about things like contact points um we can accurately describe where the contact point is or at Le more more accurately so the way it works is we divide the crown and the root separately so we'll start off with the root because it's easier so the terminology is actually pretty simple so the third that contains the apex of the root is going to be the apical third the middle one is going to be the middle third and the part closest to the CJ is going to be the cervical third and now when we divide the crown it's pretty Sim [Music] um the part closest to the CJ is going to be a cervical the part in the middle is going to the middle third and the part that contains the accusal surface is going to be the accusal third now that you have to remember that uh tooth is 3D so you can divide the tooth into thirds in several different ways um so we can also divide it this way so the middle is always going to be the middle third but now we have to figure out is this going to be the Buckle lingual or is this going to be mesial distal and I kind of gave it away because we're looking at buckly so right here is the Buckle surface so that means this has to be either misal or distal I would highly recommend that you get a typod do now or a 3D model or image of a tooth how you can Orient to exactly what we're looking at but right now what we're looking at is a mandibula first Moler if you kind of just tore away the cheek we' be looking at the Buckle surface right here so on the other side is going to be the lingual surface and so that means this side is going to be the distal and this is going to be the misal and the way the reason I know that this is distal is because the roots usually for most teeth The Roots Point dist um so that means this size is going to be the meal so now when if we rotate this 90° so now we're looking at the misal view um the Root's not going to change right if we divide the root into thirds this is still going to be the apical this still going to be the middle and this still going to be the cervical same thing I divide the crown this way it's still going to be accusal there still going to be middle and still going to be cervical now the difference is because we're looking at The misal View when we divide it this way this is going to be middle and now this is either going to be lingual or it's going to be buckle and this is going to be lingual and this side is going to be the Buckle and the reason I know that is a in terms of anatomy the Mand first Mo has a larger lingual cus and B I know that because if we're looking at this way and we turn it 90° for misal the Buckle is going to go to your left side right so don't worry too much about where where the like whether is going to lingual or Buckle what you should get out of it is the fact that you can divide the crown into thirds in three different ways one that contains the accusal cervical view one that has the distal mesial and one that has the Buckle lingual um so we could do the same thing with anterior teeth I'm just going to go through quickly um not much changes the apical is still going to be the a the Apex still going to be apical it's still going to be the middle third and the still going be the cervical third CU close to the CJ now when we divide the this way same thing this still going to be the cervical because it's close to the CJ it's still the middle it's close to the it's in the middle the only difference between this and a posterior teeth is now this contains the incisal surface so this is going to be the incisal third so again other than the fact that it's switching unisal with accusal it's pretty much the same um so that means you can divide it this way too and the Max Essential is a lot easier to figure out which side is mesial which side is lingual versus which side is um facial sorry which side is meal distal and which side is facial lingual and it's pretty obvious that uh we're looking at it head on in a facial lingual view I mean if we were to draw another tooth right here right that would be the other Central so right here is the maxillary right Central and we're looking at the facial view of it so this surface right here is a facial surface that means this side right here is going to be the meal and this is going to be the distal right this is the midline so this is the misal this is distal and of course this is going to be the middle now same thing rotate this 90° now when we divide it this way this is going to be your lingual this is going to be the middle and this is going to be your facial right you just turn this 90° the reason that we divide teeth into thirds is that way when we talk about things like contact points we can describe accurately where they are or more precisely should I say so a what of contact point is is is where the misal surface of one tooth touches the disal surface of the adjacent tooth or in the case of central is going to be the misal surface of one Central touching the meal surface of the other Central so example right here this is the distal surface of the max Central right and the contact point is where the disal surface is touching the meal surface of the lateral or in the case of the centrals you're going to have the misal surface touching the meal surface of the other now right now we're looking at this from a facial lingual view right this this is the facial surface and the axis that you can see is going to be the incisal to the gingival axis um if you contrast that with the accusal view where now the axis is going to be the Buckle lingual axis do you see what I mean right here the bottom here is the enal and the top is going to be the gingival or the cervical so this is going to be the incisal gingerol contact Point whereas this side the top is the Buckle and the bottom is a lingual so this is going to be a buckle lingual contact point so when we talk about individual teeth every tooth is going to have a mesial incisal gingival contact point a distal incisal gingival contact point a misal buckle lingual or facial lingual contact point and a distal Buckle lingal contact point now because anterior teeth are much thinner um Buckle lingually or facial lingually um Buckle lingual contact points are going to be much more prominent in posterior teeth so some rules with contact points so the distal andal gingival contact point is either the same level or more gingival than the misal andal gingival contact point and I believe this is just for anterior teeth so what does that mean so when you look at the distal contact point right for the Maxi Central this is slightly more gingerol than the mesal contact it's slightly higher and the trend moves it continues as you go to the lateral inzer right the distal contact Point here is more gingival or closer to the gingera or than the misal surface and because of that as you move distantly you're going to the diag the line is diagonal pointing and getting closer to the gingiva the other way to put it is as you go Mis is going to be more inal so right so you start distal and then as you move me now you're getting closer to the incisal edge um next rule we we'll skip this for now but the next rule is going to be all teeth have a facial lingual or Buckle lingual if you're talking about posterior teeth contact point in the middle third of the crown but posterior teeth have contact points leaning toward the facial so so this facial Buckle same thing um what that means is now when we look at this Buckle lingually right the buckle lingual axis if you divide the teeth into thirds here the contact points are always in the middle thirds and that's pretty much what it's saying no matter for all teeth the Buckle lingual contact point is going to be in the middle third so that's going to be easy to remember so what you mostly going to um be remembering when you talk about conduct point is going to be the misal and distal inis ofal Ginger incisal gingival contact points so the final rule that we have here is that all posterior incisal gingerful contact points are in the middle third of the crown except the misal surface of all MERS and that's going to be the junction of the clusel and the middle thirds um so that's just something you're going to have to remember for boards um make sure you remember the exceptions because that's usually what the boards are going to test on but um for now don't dwell too much on the rules mostly just realize what is a contact point because when we talk about individual teeth we're going to be talking about the contact points for all the teeth so just an example let's talk about the left Max lay Central right here um if we were to divide this tooth into thirds um remember this is going to be the cervical third this is the middle third and this is the inal third if we were to describe the in inal ginger contact points we would say that the misal incisal ginger contact point is in the incisal third whereas the distal incisal gingerol contact point is the is in the junction between the incisal and the middle thir right so by the junction just means where the two thirds intersect so we're going to be pretty much when we talk about all the teeth we're going to be talking about the misal and distal and cenal contact points for those particular teeth so moving on embur so what Embraer is is a v-shaped flare surrounding proximal contact areas of a tooth so so what that means is everywhere that you have a contact Point like right here you're going to have this vshape right here as you can to see and each of those are embra so there are different types of embrasures so right here we have an incisal embraser because it's the vshape formed at the incisal edge and here we have a cervical or Ginger Vol embraser U but you don't typically talk about that one as much because if you remember normally have your interdental pillow right here um so unless you have like a lot of gum recession you're not going to see your um Ginger V cervical Embraer as much um and then remember the tooth is 3D so we can look at it facial lingually you can also look at it um ol clusively or in sizely right so right here we're going to have a facial or lingual braer right here and for posterior teeth it's going to be the Buckle Ure and lingal Ure here so we have a incisal embraser and a facial or Buckle Embraer and then a lingal embrasure and so what Embraer is is it's a Spillway for food during mastication so what happens when you chew is um food can actually move through the embrasures and what that's going to do is it's going to reduce the pressure of mastication because now you have have um a place for food to escape and what it also does is it self cleanses the tooth because now when the food is moving through the Embraer um it's preventing the accumulation of plaque and stuff like that and what they've noticed is when you actually shave down the uh the incisal surface so you no longer have an embrasure what happens is food gets forced through the contact point and what that's going to do is going to irritate the indal pillar right here and it can actually cause gingervitis or um periodon itis so the rule to remember for embur is that facial embrasures are always thinner than lingual embur um and the exception to that are the mandibular centrals where the facial embrasure is the same as lingual embrasure and the max first molar where the facial Embraer is greater than the lingal Embraer so what that means is uh these aren going to these aren't very good pictures but pretty much what it means is normally the facial Embraer here is always going to be thinner than the lingal embrasure and by thinner it means like the V is going to be skinnier so it's going to be like a skinny V versus a fat V and so when the exceptions are mandibular centrals so mandibular centrals um if you pretend this is a mandul central the facial is going to be the angle here is going to be the same as the lingual side and then for Max Muller uh the Buckle embrasure is going to be greater than lle Embraer angle right here so those are the two exceptions for the embur again don't get too bogged down on the rules just make sure you know what an Embraer are and that you have um both incisal facial buckle and lingual embrasures and then later when we study individual teeth you'll learn a little bit more about the embur of individual teeth so last but not least we have Heights of Contour so what a height of Contour it's also known as a height of curvature and so what it basically is it's an imaginary line that encircles the tooth or the tooth surface at its greatest bulge so pretty much if you go back to the measel view of the Mand first molder if you look at the Buckle view here right this is the Buckle and this is the lingual we have a lingual cusp right here um the height of Contour on the Buckle side would be this right here and the height of Contour on the lingual side going be just about this part right here so pretty much it's just where the greatest bulge is so facial or Buckle height of Contours the rule is it's going to be in the cervical third for all teeth except mandibular mullers those are going to be in the junction of the cervical and middle third and then for lingual Heights of Contour anterior tee is going to be in the cervical third so pretty much for anterior teeth both the facial and the lingual hydr Contour is going to be the cervical third so that's going to be easy to remember posterior teeth is going to be in the middle third except for the mbula second premolar and that's going to be theusa third so remember we can divide this tooth into third so if we divide it this way right this is your accusal this your middle and that's a cervical now the Buckle um height of Contour is going to be the junction of the middle and cervical third and a lingual he of Contour is going to be in the middle third and does that yeah so you see that follows the rules right so the Buckle head of contour for mandibular molas is in the junction of the cervical and middle third which is this right here and a lingual height of Contour is in Middle third and that's right here Li third so um in terms of function of the height of Contour so there has been some debate of what it actually does so originally it was thought that um because you have a bulge now you have um a space for um food to move through similar to an embrasure and so they thought that that would um help self cleansing and stuff like that but they found that if you actually shave away the heights of Contour so you don't have that Anatomy anymore um it doesn't really do that much for um self cleansing um so the the actual functionality of the height of Contour has some debate to it but in terms of what they are you just need to know it's the greatest bulge and you just have to be able to describe where it is on every single tooth so that's going to be the end of our lecture for today um so just as a recap um don't get too BG down the details and the rules of the different things that we talked about today um for this for the purpos of this lecture U what you want to do is big picture what is a height of contour and how would you describe it um what an Embraer is and again that you know that you have both enal facial and buckle embrasures as well facial buckle and lingal embrasures and that contact points you're going to have the inal gingival axis and a buckle lingal or facial lingal axis and um you can describe where the misal and distal contact points are using division of teeth into thirds and next time when you learn again when we learn about individual teeth you'll learn about these Concepts and how they apply to each specific tooth and so we'll learn about that next time so thanks for listening