Posterior Occlusal Scheme PDF

So just I wanted to let you know that I did post an announcement regarding the upcoming exams, the summative exam and the written exam and the schedule for the day and the instruments that you're going to need. I just want to also remind you that the topics on the written exam will only go through D...

So just I wanted to let you know that I did post an announcement regarding the upcoming exams, the summative exam and the written exam and the schedule for the day and the instruments that you're going to need. I just want to also remind you that the topics on the written exam will only go through Dr. Escobar's lecture on Facebook and CR. So last week's topic here and this week will not be included on the exam, will only be through Facebook and CR. Okay. So from the very beginning and then the next few lectures up until and through Facebook and CR. It's two. Legs. Okay. But as far as the summative is concerned, I have a video up there just reviewing what the expectations are for the video. Summative reminder that it is an upper occlusion Rim video against natural lower teeth and the natural lower teeth will be your fixed dental form. Okay. If now the only thing on the on the video, it says that we're going to give you a record base for practice and then you're going to use that same record base for the exam and we're not going to do that. That was recorded a couple of years ago when we didn't have enough supplies. Now you have your own supplies and your kits. So if you do want to practice, go ahead and make a record base with your stern tech material. You have tons of wax so you can practice with the wax that you have. We weren't fortunate enough to have all of those supplies because of the supply chain that wasn't available a few years ago. So you can go ahead and make your own record bases and wax rims and practice if you wish to do so. Again, I will leave out equipment needed the Triad unit, the water bath, the heat paddle, and just make sure that when you're finished with it, if you're working in the SLC proper to return it back to the table, I will if you need a couple of or a just a small amount of sticky wax, come to me sometime today and I will give you sticky wax. I find that if I leave out sticky wax, I mean it's literally gone in two minutes, so I'll just make sure that whoever needs some sticky wax and literally you need like a quarter of an inch of sticky wax, you know, just to tack your rim onto your record base. Okay. Yes. Do they have the exam you're going to provide? I will provide the cast and the record base. Okay. And the wax? Yeah. Yeah. I will provide everything that you need. But I'm just saying, until then, when you practice, you have all of the consumables necessary to practice with. Except for sticky wax. Okay. Any other questions? All right. As far as your setups for today, this is obviously going to be your final project. So I'm hoping that you spent time watching the video. So to know and understand what your next step is going to be for today, I will introduce today's lab and also give you some some conversation about the completion of the setup. And well, we're going to I'll point it out to you today during lecture, there is a video up about what the final project needs to look like between the setup and the wax up. Don't confuse it with the end of the summit of the summative video, which talks about an anatomical setup. There is a lingual eye setup video, so ignore the anatomical setup video and there is a lingual eye setup video which will go through the grading rubric of the lingual ized setup. Okay, so my suggestion is make sure that you watch the videos in order and appropriately so that you are prepared for each step along the way. Okay. Again, the videos talk about not only the how to, but the why that we do it so that you understand why it's so important and us focusing on certain important areas as we do things. Okay. Any questions before we move forward? Okay. All right. So last week we started talking about denture occlusion. But from the standpoint of what we do on the anterior teeth to make sure that they're not interfering with with the patient's function. Today, we're going to talk about the different occlusal schemes that we utilize depending on the patient's presentation and why we choose what we do. So. You have. You are fully entrenched in natural occlusion. And the one thing that I want to stress and the one thing that I want to impart upon you is that denture occlusion is nothing like natural occlusion. In fact, it is the complete opposite of natural occlusion. And we're going to see why today. So the rules of natural occlusion basically say anterior contact and centric incisal guidance and protrusion canine guidance and lateral. And for the most part there is typically a discrepancy between Co or MIP and CR. Right? And you have what is called mutually protected occlusion. That's basically a summary. Well, we don't have that term in denture occlusion at all. And let's take a look. Why? So for natural occlusion, we see anterior and posterior contact simultaneously in full occlusion, in full tooth to tooth contact in MIP. When the patient or when we go into protrusion, what happens to our posterior teeth? They disclosed Exactly. And the same thing when we go into a lateral excursion. They disclosed. Okay. Canine guidance in lateral. Okay now. Resorption begins in the anterior. We learned that in week one, the maxilla reserves up and back, the mandible resorts down and forward, and that's without any removable prosthesis whatsoever. Movement of a complete denture on these already resolving bone increases the rate of resorption. So how would a natural occlusion? Design. Incomplete dentures affect this situation. So imagine you all now with the same dentition that you have in the same occlusal scheme that you have, except that what's sitting in your mouth are a set of dentures. And now you're going to go into protrusion. And now you're edge to edge. What do you think is going to happen with your dentures? They will dislodge. And the first thing that if you did that for your patient and your patient will probably say, my dentures are loose. You may have terrific retention on those dentures, but they will pop out. The lower denture will rise up. The the upper denture will come down. It will be a mess. Okay. So the Incisal guidance causes both dentures to move. The anterior ridge acts as a fulcrum and movement like this increases pressure and increases anterior resorption. Can't have that in a denture. Okay, so this is the natural dentition which has incisal guidance in protrusion. Okay. That's a problem in a topical denture. What we try to do is when the patient moves forward or even lateral, what we try to do is create a balance so that when the jaw moves forward or even side to side, the teeth are in constant contact and the teeth contact simultaneously, not only in the posterior, but in the anterior, not only in the anterior, but in the posterior. So we keep the anterior teeth apart when the patient is in centric. But when the patient moves forward, for example, to incise something. Those posterior teeth are set in such a way that they remain in contact at the point where the anterior teeth begin to contact. Okay. And that's called a balance. So we need to balance those contacts. Same thing with canine guidance. The canines causes both dentures to move. If it has mutually protected occlusion. A single anterior point acts as the fulcrum movement causes pressure. Pressure causes resorption. And so we do the same thing on an anatomical denture as the patient slides to one side, the cusp tips or whatever curves we build into the setup will contact not only on the working side, but if we take a look at the other side, which is in natural occlusion, we call it the non working side, right? But in a denture occlusion, we call it the balancing side. Okay. So on the balancing side, we also have cusps that are in contact. And that's how we balance the occlusion by setting the teeth in such a way that they will continue to touch even when we have protrusion or a lateral excursion. Okay. So that's a balance. We have bilateral posterior balance in all movements. So how do we change from natural occlusion to denture occlusion? Okay, so here are our rules in natural. Our rules and denture are no anterior contact and centric. We saw that last week when we started to set our anterior teeth. They needed to be some horizontal over jet and we needed to decrease the vertical so that we didn't have any vertical overlap. We have no incisal guidance, no canine guidance. And as far as our centric is concerned, our first contact is the only contact. In other words, patient doesn't hit and then kind of slide into centric. So it has to be that only contact. Okay, so co equals cr MIP equals CR. We have to go into that repeatable centric relation position all the time. So that there's no movement. Our fixed occlusal factors are centric relation. It's repeatable. If we can put that patient into that same position time after time after time, then we know that the at least we can come up with a stable point of reference that we can go back to every time. Our horizontal and vertical inclination are are also fixed factors. We can't change that. That's condole or eminence. What we can alter, though, is the position of our teeth. We can change the horizontal and vertical position of our anterior teeth. And what we're going to talk about today is the cusp height of our posterior teeth and the curves that we can build in to the posterior occlusal plane. Okay, So we can change and play around with these four factors in order to obtain and achieve this balance. So last week we saw this. Last week we saw natural contact. Well, we compared our incisal edges with natural contact, which is totally fine. We have a situation where if we have a flat plane, we need to make sure that the incisal edges are far enough apart, that they don't come into contact unless the patient is pretty much translating. And then there's going to be enough horizontal over jet to accommodate. We can also decrease the vertical overlap so that those teeth will not the size alleges will not contact. But if we have built into the posterior some cusps or some curves, we can also build into the anterior a little bit of vertical overlap so that the patient doesn't appear that they have an anterior open bite. Okay, so what do we do in the posterior? We have a couple of options. We have an option to have a flat plane with cusps. We have an option to have a curved plane with cusps. Okay. And that curved plane, we know it as curve of spee. In a frontal view, we are flat plane. With cusps. That is an option which actually we're going to entertain today. And then we have a curved plane with cusps, which is our curve of Wilson. Our cusps that we're entertaining working with are zero degree ten to 20 or 30 degrees. So fully flat, fully anatomical and a semi anatomical tooth. So we have three occlusal schemes, a fully anatomical occlusal scheme. We have our flat oops, sorry. We have our our flat tooth on a curved plane and then we have a flat tooth with a flat plane. Now sometimes you do want to use a flat plane, but there's not enough room to build in a curve. So we have options for that as well. So let's take a look at a number of different options. So the first option is a monoplane tooth or a lingual tooth, which is this is basically what we're going to embark on today. We're going to be setting a lingual setup with a flat plane lower, so a zero degree lower and a 20 degree upper. But we're setting it on a flat plane with one exception. And that's going to be the very last tooth in the arch. So a monoplane occlusion is an occlusal arrangement where the posterior teeth have surfaces that lack any cusp height. It's just flat. Okay. So here we have no anterior contact. And in the posterior we have a flat occlusal plane. Flat with a flat tooth and a flat plain looking at it from the anterior, it may result in group function if the canines are far enough apart. So if we take them out of the equation. And the patient slides in a lateral movement. One side may still remain in contact the working side, but the balancing side may open up. Same thing on the other side. So why do you think that is? If we take our monoplane set up and the patient goes into protrusion, it may result in incisal guidance in protrusion unless there is sufficient anterior vertical horizontal over jet or. Decreased vertical overlap. We're going to open up the posterior. Think back to what you know, in natural occlusion. Okay, let's put it on an articulator, which is supposed to simulate our patient. That type of occlusion could potentially work for patients that have zero degree consular inclination. But how many patients have that? Not many. Okay. Where the maxillary occlusal plane is parallel to the path of the condyle. But not many patients condyles are zero degree. So when the patient goes into protrusion, what happens? It opens up posteriorly because what's happening with the condyle? The condyle is is curved. Or the consular eminence is curved. And so when the eminence is curved, we have an opening in the posterior because it wants. It takes that same trajectory. Resulting in incisal contact or possibly even incisal guidance. So this is known as Christiansen's phenomenon. Looking at it both laterally and anteriorly. Or frontal view. Okay, so here's the patient in contact in centric relation. The teeth are far enough apart. But again. If the occlusal plane is flat, but the mandibular path is curved. Then what happens is the posterior teeth will disclose in excursions. The same thing happens going laterally. Okay, So the potential solution is let me back up again. The potential solution is as the patient moves forward, it's fine and centric. But as the patient moves forward, we need to fill this gap in right here. Okay? And so what we're going to do is fill that gap in with one of a couple of things. We can either fill the gap in with a curved plane or we can keep the plane flat and then just take the last molar and tip it upwards so that when the patient moves forward, it's going to hit the tip tooth. So it really depends on the size of the residual ridge and how much room there is. Okay. And it's really on a case by case basis. But what's important is this compensating curve. So a compensating curve. And you must know, because the definition of the compensating curve is the same, whether you're compensating for natural or denture occlusion. A compensating curve is a curve of the occlusal plane that compensates for the curve of the articular eminence. Okay. Curved planes maintains posterior contact longer than flat planes, obviously, because when the patient moves forward, these teeth still remain in contact. Whether you have the entire plane in contact or you just have one posterior contact, as long as you have a minimum of one posterior contact at the same time, the anterior or contacting your setup still remains in balance. Okay. I see a few nods. I know this is something that you kind of need to wrap your head around a little bit, but are there any questions? Professor, this content should be retained or have. That's a very good question. Should it be with teeth or can we substitute maybe some acrylic back here? So it's either or. Sometimes you may not have room for a second molar. And if we don't have room for a second molar, then you can add some wax back here and the wax and you've seen it on the video. On the video we added wax because we didn't have room for teeth. This year we've adjusted the size of the teeth depending on where your setup ends up on your ridge and we should end up about the same place. But if we don't, I need you to show it to your faculty. You may not be able to have room for a second molar to tip. And if you don't, we're going to have you add some wax there in order to balance your movement. Great question. Thank you. Yes. And I will I will demonstrate this to you with two different setups. Right before we start doing our setups today. So the problem with the first molar is it's not necessarily the tooth is that if these two teeth, if the upper and lower first molars end at the same position, then if you do it with the first molar, you're going to potentially. Potentially offset your occlusal plane. So again, it's. I don't want you to shorten your occlusal plane. So you basically need to look at on a case by case basis. So once again, a curved occlusal plane. So here, as you can see, we have a curved occlusal plane. But with our setups today, since we're starting off at two thirds, the height of the pad, if we take our first molar and turn it upwards, there's a really good potential that we're going to be ending up with an occlusal plane that's too high. Okay. So that's why we might just keep our occlusal plane up to first molar at two thirds and then just tweak the second. The occlusal plane is curved, the mandibular path is curved posterior will the posteriors will remain in occlusion in excursions and not only in protrusion, but also in lateral. So we might want to tip it up Buckley as well. But because we set the anterior teeth with with enough over jet, we shouldn't have that problem because we can easily fix the anterior teeth. Much easier than balancing the posteriors in protrusion. So again, these are just the definitions we discussed. The compensating curve balance requires a compensating curve regardless of cusp height. So we can technically balance even a flat plane tooth by providing that extra posterior contact. Okay. So that again, when the patient goes into protrusion, that anterior, those anterior teeth will have a concurrent a simultaneous posterior contact. A balancing ramp. Is what we were talking about when a compensating curve within the occlusal scheme is not possible. We balance the anterior teeth going into protrusion by placing a second molar or wax, which will ultimately be processed into the denture and it will be part of the denture base acrylic. So a balancing curve is a curve of the occlusal plane and the curve of the teeth. A balancing ramp is either an angle tooth or wax at an angle to create that curve with one additional tooth or angulation. Okay. So this is what your setup will or similar will look like. A monoplane of flat against flat will look like your flat planes with no intercut station. You can't really tell looking at it from the front, but you can certainly tell looking at it from the side, there is sufficient horizontal over jet so that when the patient comes forward, the teeth will remain in contact. And because we have sufficient horizontal over jet, the anterior teeth will not come into contact with each other and create that movement or that pressure or that incisal guidance. Okay. Here the anteriores do appear to have overlap, but they don't. They may have a little bit of vertical, but again, because there is sufficient horizontal. So kind of the rule of thumb is for every millimeter of horizontal over jet, you can have a millimeter of vertical overlap because that will compensate for the for the overlap. The over jet will compensate for the overlap. And by the time the incisal edges will approach one another. So we've got about three millimeters out, the condyle will be translating. So again, increase horizontal decrease vertical. And then there's your increased horizontal. Advantages and disadvantages of this monoplane setup. So it's the easiest to set up the potential to be the least harmful on the ridges. So we talked about the severely reserved ridge, the patient for that who has poor neuromuscular control, best for poor quality ridges and can be used either in a class one or certainly a class 2 or 3 situation where we're not really sure where it's going to wind up on the mandible if the mandible is smaller or larger. Okay. And certainly in cross bites. Okay. So you have freedom to set these teeth wherever you need to. The only thing that you have to keep in mind is, for example, if you're going to set this tooth in cross bite, you need to have at least that 1mm to 2mm of offset so that the reason why we set the maxillary teeth one and one half to two millimeters buckle to the mandibular teeth is to prevent cheek biting. Okay. We don't want to set these teeth edge to edge. So if you're going to set the mandibular teeth and cross bite the buckle cusps, if you will, and we don't really have cusps on a monoplane tooth, the buckle of the mandibular tooth will need to be one and a half to two millimeters. Buckle to the maxillary tooth to prevent cheek biting. Okay. So never edge to edge. Disadvantages. We talked about the conflicting evidence last time on chewing efficiency. Patient must be coached to chew on both sides of the arch, small bites placed on the left and right of the posteriors. But, you know, when it comes down to it, it's pretty much on all denture patients. You don't really chew a solid bolus of food on just one side, regardless of the occlusal scheme that you have anesthetic compromises with a flat plane, maxillary tooth, it may be difficult for patients to accept so but if there are stronger indications to have a fully monoplane occlusion, then that kind of outweighs the esthetic issues. Now let's take a look at your setup, which is going to be the lingual setup of the flat plane lower with a 20 degree maxillary tooth. Okay. So what we're going to add on the Advantage column is that chewing efficiency may be improved due to the maxillary lingual cusp because now we have that supporting cusp, but we also have a cusp that is able to trichet the food a little bit better on the flat surface. Esthetic compromises do improve now because of the esthetic buckle cusps. So now it looks more like a natural tooth. So that's in the plus column. And as far as the negative column is concerned, again, as I mentioned, as far as chewing goes, a new denture wearer would have to be coached on how to chew their food simultaneously on both sides. You should try it once and see. Think about when you chew your food. Do you chew on one side or the other, or do you chew on both sides at the same time? But if you're going to coach your patient, you try it anyway. So. So let's take a look at again your lingual eyes, denture occlusion and how we're going to facilitate that. So this setup is used to compensate for anterior esthetic issues. This is a lingual ized setup with a curve built into the occlusal plane itself. But it's utilizing a flat plane tooth. Again, it's compensating for the curve of the articular eminence. It allows for anterior vertical overlap. So some patients do have steep overbite to begin with in their natural dentition. And if we try to unwind these teeth and if we try to reduce those steep over bites because of skeletal formations, sometimes we do have some phonetic changes and some esthetic changes. And so what we're going to need to do is build in a more significant curve, but we may not be able to completely. It might be nice to add some cusps, but we may not be able to, maybe due to the ridge height or to or to the quality of the ridge. So we're going to do it in this fashion. It introduces curves of Spee and Wilson, which gives us to the ability to produce a more balanced occlusion. It will give us bilateral posterior contact in centric bilateral posterior contact in protrusion and lateral and. But we still have to maintain no anterior contact in centric or lateral and anterior contact in protrusion only, which means anterior contact and terriers may touch with bilateral posteriors and terriers may not touch if the posteriors are not in contact. So again, we're focusing on balance. Balanced occlusion requires absence of anterior contact and absence of incisal guidance, canine guidance and the presence of a compensating curve. If it's in the occlusal plane, that's fine. If you have a balancing ramp, that's fine too. Okay. So let's take a look at what this is going to look like. Once you have your curve, it may result in balanced occlusion if the A.s are far enough apart and the posterior curves are in harmony with the A.s. Same thing holds true on lateral excursions. It may result in balanced contact on both the working and balancing side if they are in harmony with the with the working side. Okay, so now let's take a look. Advantages and disadvantages. Allows for a more esthetic, vertical and horizontal placement of mandibular interiors and posteriors allows for limited ability to incise food. It gives better support and less movement during posterior occlusion due to balance. So, you know, when a patient now has a balanced occlusion, they feel more confident. They feel like they have more stability in their denture and the denture seems to the patient to become more retentive again when a patient comes in and something is wrong with their denture, but they can't really articulate what the problem is, a lot of times they come in and say something is wrong, but I just don't know what it is. Or the denture feels loose. More times than not. It's not your impression or it's not the fit. More times than not, it's generally the occlusion. More complaints, more sore spots, more denture. Issues arise because of poor occlusion, poor occlusal schemes, poorly executed occlusion or poorly adjusted occlusion. Then any other issues involved in denture fabrication? When properly done, supports joint movement and lessens stress on the TMJ and then on the disadvantaged side may not be able to resolve very deep vertical overbite again because you're dealing with a monoplane lower. So not until you introduce cusps will you be able to really uncouple the anteriores in such a way. Okay. But it's it's, it's moving more towards being able to have a more esthetic vertical overlap. There is a procedure called a clinical remount, which is done at insertion of a set of dentures, which of course we're going to learn about in a couple of weeks that clinical remount is doing an occlusal equilibration at denture insertion, but it's done extra orally so that we can make sure that the occlusion is completely refined and perfect before we dismiss the patient. The more curves and the more cusps you introduce into a into an occlusal scheme, the more it will be necessary to do a clinical remount, the more critical it will be to occlusal equilibrate indenture. And conversely, if done incorrectly, can drastically increase denture movement and TMJ issues. Okay, this is your recommended occlusion for an implant retain mandibular over denture and all digitally fabricated dentures there. There is a there are quite a number of studies out looking at whether or not, you know, which is the best occlusal scheme to provide our patients with. And you know, the average patient, the average class one patient with a well fabricated denture will generally thrive no matter what occlusal scheme we provide for them as long as the as long as the occlusal scheme and as long as the occlusion is managed properly. Now, there are a number of exceptions, again, as we mentioned, due to resource bridges, due to neuromuscular health, due to patient coordination and things like that. But, you know, the jury is not you know, there is not strong evidence for one single occlusal scheme or another. But on the spectrum of fully flat to fully anatomical the lingual eyes, occlusal scheme seems to be the one that has provided the most benefits to the most patients and clinicians and technicians because of it being the easiest setup and the most esthetic. And has the most longest term success for our patients. So we basically go by that and move forward and teach this on a pre doctoral level. Now, as we look into the anatomical denture occlusion, which is. The closest resemblance to those of a natural, healthy dentition. They have some require much more detailed in terms of setup and maintenance in in a denture. So again, this is a side view of an anatomical setup. But as you can see or and as you can see, it still must abide by the rules of no anterior contact. It will incorporate curves of spee and Wilson. And as you can see now, we have a fully faded tooth. When the patient goes into protrusion, the teeth continue to maintain contact in protrusion as well as in lateral excursions. It will result in balanced occlusion if the anterior are far enough apart and the posterior cusps and curves must be in harmony with the anterior. Same thing again in lateral excursions, we have a bilateral posterior balance cross, arch and cross tooth. Both left and right. Due to the absence of canine guidance. Let's take a look at some advantages and some disadvantages of the anatomic denture occlusion. It does give a nice esthetic result. It keeps the posterior teeth in contact the longest. Okay. Because of the inclines. As you can see, this protrusion of movement here and best for balanced occlusion, best for the ability to incise food. But sometimes it is when you there's an expression enter bolus exit balance. So if you're going to put something between the incisal edges that still disclose the posterior teeth and sometimes that can be an issue as well. It is the most difficult of all denture setups to do well. It requires additional records before articulating. It requires protrusion and lateral check bites. It requires a semi, at least a semi adjustable articulator. You can't get away with a rat trap and of course, face bow and centric relation mounting. If done incorrectly, it causes the most lateral and rotational forces and the most bone resorption. That's if the patient can tolerate this setup. If the occlusion is not balanced, if the occlusion is slightly off, if the patient winds up hitting on an incline and not cusp fossa, you know, patients usually have very low tolerance to poor occlusions. Again, when they come in and they say something is wrong. And I but I just can't explain it. Most of the time they'll just take their dentures out and not wear them or wear their old dentures, which are their old comfortable slippers. Right. The posterior setups are typically shifted, slightly lingual just to stabilize that mandibular denture. And we do lingual eyes those setups basically to resist lateral forces. If you think about the the lower ridge, think about the wall that the residual ridge will create. And we looked we talked a little bit last week about the vertical walls of the mandibular ridge. And so if you have a higher vertical wall, it will have a tendency to resist lateral forces as opposed to a lower vertical wall or even a flat residual ridge. It has no resistance to lateral forces. So just imagine an anatomical setup that is maybe just slightly off in the patient goes into lateral and instead of resisting that, I mean, literally the denture will just slide right off the ridge. So again, that's why we say things like the flatter the ridge, the flatter the tooth, because it just can't hold up to those lateral shear forces of both buckle and lingual cusps. It absolutely requires a clinical remount to do a proper occlusal equilibration. And as bone resorts and changes occur to the denture based foundation, the occlusion will change. And so annual recalls are critical for our completely edentulous patients with I mean, annual recalls are very recommended for our denture patients in in general. But for anatomical denture patients, we need to make sure that we evaluate their occlusion because occlusion can result easily with our anatomical denture patients. More frequent recalls and adjustments are recommended and are usually necessary objectives. Let's say. Let's take a break. Yeah, ten of nine. Come back at nine. Please be. Careful again. I was. I didn't have it up yet. Oh, okay. I'm sorry. That's okay. All right, let's. Let's get started. So comparing monoplane on a flat plane are incisal edges. Once again, we can't and shouldn't go past that occlusal plane for an anatomical tooth with a curved plane. We can because we have the posterior cusps that will enable the anterior teeth to rise. And then by the time the incisal edges go edge to edge, it will be balanced by the cusp tips in the posterior. Okay, So here basically what we've what we've been talking about, no vertical overlap unless we have that posterior curve or compensating horizontal over jet in here, we can have a millimeter vertical overlap with 1 to 2mm of horizontal over jet will that will help compensate for any of the the vertical overlap that we have. Okay. Now I had a question as far as why we're using the two thirds, the height of the pad and why we're starting at two thirds and why anatomical and so basically on when we're using a flat plane and we start at two thirds, we're ending at two thirds. Okay. In this case, if we start at two thirds and we end at two thirds, we can't really add on an additional curve. We can't build it in if we're already starting at two thirds. So if we need to build in a compensating curve, a balancing ramp, we're going to have to do it with either wax or tilting a tooth, because otherwise we're going to end up with a curve that's too high. So therefore, when we do an occlusal scheme that has a compensating curve built in, we need to make that decision before we actually create our occlusion rims. Because if we decide that we're going to start on occlusal scheme with compensating curves, we're going to build our occlusion Rim beginning at one half the height of the pad. Our wax rims are going to be at one half the height of the pad so that by the time we end, whether it's a flat tooth on a curve or an anatomical tooth on a curve, by the time the curve of spee is finished. It's going to be at no higher than two thirds the height of the pad. Okay. So that's the difference between when we're fabricating our occlusion rims. We need to know in advance what we're thinking of for an occlusal scheme. And that's not too difficult to do because you've already examined your patient, you've already diagnosed your patient, and you're going to be pretty certain where or how you're going to build the patient's occlusion in terms of the resort bridges and things like that. And if you find that you're going to change your mind from two thirds to one half or from a flat plane to a curve plane, once you have your case mounted on an articulator or even if we're scanning it and going the digital route, you can always change that occlusal plane. You can always change your wax, You can always change your virtual occlusal plane before you go ahead and start setting your teeth. So again just looking at this our monoplane. Starts at two thirds. End of two thirds anatomical starts at one half ends at two thirds. So arrangements of the posteriors. We look at the crest of ridge, we look at the retro molar pad and of course we adjust the overlap. Our posterior crustacean can be anywhere from 0 to 30 degrees. We're going to be using our zero for the mandibular teeth, 20 degrees for the maxillary teeth. And let me explain to you what that lingual eyes means. Basically, the concept of a lingual ized occlusal scheme means on the lower arch, we're going to be selecting a either a flat plane tooth, a zero degree tooth, or maybe a ten degree tooth, whereas on the maxillary arch it could be anything, any type of semi cusp or fully cusp tooth. So there's just going to be a difference, a gradient between the maxillary tooth and the mandibular tooth, a lower cusp on the mandibular arch, a higher cusp on the maxillary, the average, the typical difference is. Usually it's 20 degrees on the maxillary arch and it's 0 or 10 degrees on the mandibular arch. When all of our digital cases, when we start learning about it. And of course, as we send our cases off to the lab that works with us, all of our digital cases will be 20 on the maxillary, ten degrees on the mandible. We're going to be working with zero and 20. Okay? So this is monoplane posteriors that require the lowers or area C which are set next. So this is basically what your setup is going to look like. The monoplane lower posteriors are going to be centered to the ridge. So this is what it would look like if you didn't have a record base. Make sure that your lines are visible on the land With your record base on you will not be able to see the residual ridge. So transfer the line, make sure it is visible on the land, and then you can go ahead and maybe even scribe your line on the wax rim itself. And then we're going to go ahead and make sure that the tooth central fossa goes right through the scribed line. Okay. You may find that when you remove the bits of wax that you're going to need to remove to set the tooth, you may wind up hitting the record base if you do. And you need to adjust the record base so that your tooth sits upright. Remove the record base off the cast. Don't adjust your record base sitting on the cast because if you do and you're perforate the record base, you'll wind up grinding the cast. So I don't think the record bases that were made for you are pretty thin. So I don't think that you're going to have to grind the cast, grind the record base. But if you do bang into the record base, it's usually backed by the molar because that is the most or the least amount of space that we have. And why is that so important? Well, we're going to see that in just a minute. So, again, transfer the ridgelines onto your wax and begin setting your teeth. You can use the occlusal plane. Now, the the image that you saw of setting the lingual lowers on a curve was you have this zero or flat occlusal plane. The image that you saw a number of slides ago was actually on a curved plane. So it's actually pretty easy to set it on a curved plane. But we were not sure if you were going to get your the curved plane in time. So we made the decision to set everything on a flat plane, set one tooth at a time if and set one side at a time. And the reason why we want you to set one side at a time is so that you don't lose control over the case. If you have your wax rim on the other side, at least that is going to help you orient your occlusal plane. Okay. If you do one tooth like first pre molars on both sides and second pre molars on and the wax is still warm, you can wind up losing that occlusal plane. So I want to set one side at a time to maintain vertical and your occlusal plane. The entire surface of the tooth must touch the plane. Remember, we don't have cusps Now. This is a flat plane. So look at this from the lingual side. And you see how it is perfectly flat coming straight across. So if you put this occlusal plane across the tooth, both buckle and lingual sides of the tooth or the entire occlusal plane is going to touch the cookie, the metal occlusal plane, or we call it the cookie. Okay. So that is going to be completely flat. Now, what I mentioned before, if you find that the buckle ridge lap of your molar is going to hit your record base, it is likely that that molar is going to tip. If the molar tips only the buckle cusp tip or there's no custard but the buckle surface of that tooth is going to touch the plane. You need to upright it if you can't upright it because it's hitting the record base, that's where you have to grind, not the tooth, but the record base. Okay. Make sense. Okay. So lower Central Forces Center to the posterior crest of Ridgeline. And we're going to set as many posteriors as can fit on the mean occlusal plane, which is, for your case, potentially one molar. It could potentially be a second molar. This case is a little arch is a little bit smaller than yours. And these teeth are a little bit larger than yours. So if we have enough room, we may go ahead and set a second molar. We may actually wind up taking our second molar and cutting it, cutting off the distal just a bit so that we can set it. We don't want to set any teeth once the ramus begins to rise. So once we get here, what I would suggest is I'm going to have you set both sides without a second molar first. Okay. I want to get first centric on both sides. Then we're going to see how the maxillary and mandibular teeth line up and see where the maxillary mandibular first molars line up and then we'll make the decision whether or not to add a second molar and tip it or add wax for the compensating curve. And I will give I will show you two different setups that I have in the lab, whether your setup looks like one or the other. Okay. On a flat tooth, flat plane. All lower teeth must be centered to the residual ridge. So what I want you to do before you actually start setting your posterior teeth today is make sure you get your anteriores very closely inspected, not just to get a signature, but really to make sure those lower anterior teeth are over the ridge. Because if I can't see this land, then your teeth are too far forward. If your teeth are too far forward, you're going to start your setup too far forward. Okay. And that's going to be an issue. It's going to be an issue for your setup. But if this went into a patient's mouth, it would be an issue for the lower lip. Okay. So I want to be able to see this land and you want to see the land lines and you want to make sure that the line goes right through the singular and onto the anterior Ridgecrest line. Okay. If you're really being. Compulsive about it. You can line up the buckle surfaces posteriorly. That's fine. It doesn't have to line up. But if you want to be my guests, because ideally that's what should happen. Okay? From the height of contour of the cusp all the way back to the first molar. All the lower teeth must touch the plane. The monoplane posteriors must include the entire occlusal table, not just the buckle tips of the monoplane posterior. So they should not be tipped. They should be upright and flat. Plane against flat plane. I can't stress that enough. Okay. Flat plane against flat plane. Lastly, and you're not going to be having a flat plane upper. You're going to have a lingual upper. But I'm just going to finish this setup and a lot of it will be similar to what you're going to do once the maxillary posterior teeth go in, all these teeth are going to be in wax. Okay. Once they're in wax. And I know that last week I didn't see any articulator pin on the articulator. And I understand why because you are setting anterior teeth. But this week all pins must be on the articulator. Okay. Because the second you start removing posterior wax. What's holding vertical. The pin and the pin only. Okay. You have to be really careful, especially if you're holding that metal cookie on the occlusal table and you're squeezing it. You can intrude those teeth just like that. So you want to be sure that you've got that pin on and you're checking vertical every single second. Because if it's not 36 and you've lost vertical, no amount of crying is going to get that 36 back. We're not going to say, Oh, okay, you can do 35, right? It has to be 36. So keep the pin on. Keep the pin on when you have your lingual ised teeth on, you still need to see a reveal of one and a half to two millimeters and that reveal is to offset one arch over the other. And why are we offsetting the teeth? To prevent chik biting. Okay. So one and one half to two millimeters horizontal over jet of the posterior teeth to prevent chik biting the patients in cross bite. We do the same thing. Check the alignment of the buckle heights of contour of the cusp through the molar. Because they should align as well. Lingual views should show, well, not on yours. But again, notice how flat these teeth are. The Anteriores do appear to have a vertical overlap, but in fact they don't. Now this is your your setup, except it's not on a curve. It's going to be flat, but it's going to be very similar. You have a flat or a monoplane tooth. Again, all. Of the mandibular teeth are set over the ridge. The maxillary lingual cusps only will now be in contact with the mandibular central fossa and cr. The anterior teeth will have a horizontal jet. Zero to none vertical overlap, if at all. The buckle cusps will be again. You can kind of see that there's no contact on the buckle cusps, but because of the way this is filmed or photographed, it looks like there's contact, but there is not from the lingual. So this is working and balancing side. You want to be sure that you have only one contact and that's the maxillary lingual cusp. Right balancing, buckle and lingual. So you have your lingual contact and you have right balancing with the lingual and in protrusion, you have your contact. And here is your posterior contact and on. You can see one posterior contact with the second molar, one second molar contact, which will balance the anterior contact. Okay. Any questions on the lingual I set up? Okay for an anatomical setup. The anatomical posteriors are set in a slightly different order. I'm missing a slide. Okay, So if we have a second molar, you know, we're talking about aligning the buckle cusps on on the on the maxillary arch. The second molar aligns the height of contour with the first molar, and that's called the facial curve. And this is our occlusal view. Okay. Then we have so we have three curves. We've got the facial curve, we've got the curve of Wilson and the curve of Spee and our anatomical setup on the maxillary arch to begin to create that curve of Wilson and curve of spee. We have basically our lingual cusps, most of the lingual cusps, with the exception of the second molar on touching the occlusal plane. So our first premolar, we have both cusps touching the plane, second premolar. We only have the lingual cusp, touching the occlusal plane, the first molar. We have the medial lingual cusp touching the plane, and then the second molar is proportionally raised up, both on the medial and distal lingual and then, of course, on the buckle. So now if we look at the buckle side, we have the first molar buckle touching first pre molar buckle, touching second bicuspid a little bit raised up first molar, little higher than that and higher than that. And then the second molar. Okay. So each one has a step upwards as the teeth are set in the arch. So by setting the teeth precisely, it's easy to establish centric and excursions. If we look at this in profile, we can see the step upwards. So again, here's our two premolars, the buckle cusp of the first premolars touching here. We raise it up about a half a millimeter. Here is maybe a half a millimeter higher than that. Half a millimeter higher than that half a meter. Amelia Higher than that. So we're establishing our kind of our two curves of spee with our buckle cusps and our lingual cusps and. The space between the. Two. Is our curve of Wilson. Okay, so. As we have these gradual rise, the gradual rise creates the curve of our occlusal plane. On the lower. When we look at where we're setting the teeth. We talk about setting the teeth over the residual ridge, okay. Or in this area from the distal of the cusp. We take a line and we draw a line all the way back to the lingual portion of the retro molar pad. We go back to the distal of the cusp and we take a line and we draw it all the way back to the buckle portion of the retro molar pad within this area. We call that pound triangle and pound triangle. Basically is where our mandibular teeth should be placed. So the posterior teeth or. All of our teeth need to be placed where our natural teeth originally or originated. Okay. The retro molar pads should always be taken into consideration. We're emphasizing center to the residual ridge. We're also asking you to take a look at what we call pounds triangle. So you're somewhere within this region. The other thing that we're asking you to do is when you go ahead and mount your teeth, either on an analog articulator or a virtual articulator before you actually set the teeth, what you want to do is remove your record bases and evaluate the residual ridges that appear without the record bases and you want to evaluate them with its relationship to one another. Okay. Many of your patients will, of course, will be in Class one ridge relationship, but some of your patients won't be. And if they're not, you don't want to make them or place the teeth where they don't belong. For example, patients who are skeletal class two, skeletal class three, or perhaps need to be in Cross Bight. So what we want to do is we want to evaluate these for the presence of the soft tissue and for the relationship between the two ridges. So in this case, we have a maxilla that may or may not be average size. This maxilla perhaps is when compared to here, a little bit smaller, the mandible might be a little bit bigger. And in this case. The if we set the teeth where they belong over the ridge and we go ahead and set the maxillary tooth to articulate with the mandibular tooth in a class one ridge relationship, what we have is we're going to be forcing this denture flange way out into the vestibule where the tooth really doesn't belong. So if you place a tooth in that position and you realize that this doesn't look right, it probably isn't. So before you go ahead and just make everyone a class one, you've got to you've got to make this these evaluations and look at your mounting and say, all right, is this what I really have with my patient? Does my patient really exhibit these tendencies of being a class three, of being a cross bite? Or is my mounting correct or incorrect? So again, what what we're saying is look for expected anatomy. Look to make sure that your mountings correct before you proceed. Okay. So in this case, the Ridge relationship on the left side of this patient is probably correct. The Ridge relationship is also potentially correct on this side, but maybe we need to reverse the two setup and place this patient into a cross bite. And if we do, maybe the teeth that we've selected for this patient is not the right occlusal scheme. So these are all things that will affect our decision making process. In order to compensate for increased lateral forces. As I mentioned earlier, during excursions, the anatomical setup is legalized slightly. So within Pound's triangle, we get those teeth a little bit more lingual again, because of the the two supporting cusps that are now available to us within the anatomical tooth. So let's take a look at what an anatomical tooth setup is. This setting of the maxillary centrals are the two really most important. There's two pairs of teeth in an anatomical setup that are two very important pairs of teeth. But the maxillary centrals are central to the placement and ultimate position of the rest of the setup. Followed by. Again, we go to the posteriors where we see the axial inclinations of the premolars first completely upright and perpendicular to the occlusal plane. And remember how we said we had a gradual increase to begin to create the occlusal plane as well as the curves of spee sorry, the curves of Wilson. So as we begin to raise both the buckle cusps and a little bit of the lingual cusps, we're beginning to introduce the curves of Spee and Wilson. The maxillary setup is complete and now the lower first molar is the key tooth in the lower arch. In order to basically complete the setup so that the medial buckle cusp of the maxillary first molar aligns with the buckle groove of the mandibular first molar. If we can get these pairs of first molars to line up, literally be in occlusion and go through excursions and it works well, you can safely begin to set up the rest of the setup. Okay, so we've got that those two lined up. Second molars and second premolars go through excursions. And then finally, the rest of the teeth. We need to make sure that the posteriors are in precise intercalation and in excursions. Before we set up the rest of the teeth, we leave the lower anteriores for last. Because again, we have to make sure that the posteriors are set in such a way that will balance out the anterior tooth position. The mantra mandibular anteriores will contact in protrusion but not in centric and will contact based on the amount of curvature that we build in the posterior and the steepness of the cusps. So we literally put the case in protrusion. Take a look at the position of the cusp to cusp contact in the posterior and then set the mandibular anteriores according to that so that when we go back into centric, it will naturally appear how much horizontal and vertical will be present in the case. Vertical overlap is created by going into protrusion. And finally that first premolar is added and everything is adjusted out. We look from the posterior and we make sure that there is no daylight and no contact in the anterior either. So you can see that we have significantly more vertical overlap than we would if our cusps were flatter or our curves were flatter. Always check from the buckle and lingual as you set teeth. Here we have a comparison of our fully anatomical setup, our lingual eyes setup. This is a lingual ized 20 with a ten degree lower. And then this is a monoplane 0 to 0. So as I mentioned before, this just a couple of systematic reviews and I didn't remember whether or not I put this evidence or literature in here. But again, as I mentioned before, the average patient does well on an on an excellent denture fabrication in pretty much any occlusal scheme that you will provide for your patient as long as it's appropriate for the denture patients, what the denture patient presents with. And so things that we select for the patient, we're looking at the patient's ridges and other factors of things like coordination and angles, classification and cross bites. So how does two selection affect occlusion? Cusp teeth deliver greater lateral forces than flat teeth. As you can see, the mandible moves to one side and things are very much locked in. So the balance is the only thing that is going to help support those dentures, but it will go out of balance. Or out. Of contact quicker. Anatomical delivers more lateral force. On the ridges, but it maintains balance or the contact longer. So how to decide which to use? Check your residual ridges and your ABC's the angles classification and cross bites patients para functional habits or neuromuscular reproducibility. As far as bone loss and denture occlusion go. Again, no anterior contact to decrease the pressure, no incisal guidance or canine guidance to decrease movement. And first contact is the only contact, no hit and slide. To decrease movement, we need to decrease. Pressure. Decrease movement, decrease resorption, which is our silent enemy. We need to prevent anterior occlusion by increasing our horizontal over jet and decreasing our vertical overlap. We need to maintain our posterior occlusion by increasing our cusps and curves. If it is available to us and the patient, it's appropriate for our patient and that is it for us today. I'm going to reserve. I don't think that you have the wax up in your PDF Hold on. Attendance. And so make sure you get your anterior set up. Looked at not for the signature, but make sure it's right. That's just okay. Just make sure it's correct. If you don't feel comfortable with your anterior setup, just make sure it's correct. Ask somebody. You have a question. Do we have a quiz next week? Next week is the exam. Oh, no. Are everybody? Yeah. No, because you have an exam next week. I'm not going to give you a quiz next week. Thank you. You're welcome.