JAN 26TH 2024.docx

So we had a new patient. They called, they said, I need to come in. I broke something, they weren't sure what it is. Patients very often don't know what it is. Right. So they come in. This is the X-ray that was taken. I'm sorry for the way it presents. You know, I took a picture of it with my iPhone off a computer screen. So, you know, it's not great, but that's what we see right now. This obviously is going to need to be restored, right? So we look in the mouth and here's what's broken. The final tooth was a full contour zirconia crown. Right. You can see that this is either gold or full contour zirconia. It's going to present that way. You guys are probably pretty familiar with reading radiographs. But you know you can always tell by the coloration of things whether you're looking at amalgam or composite, whether you're looking at a metal post, whether you're looking at a fiber post in a canal, whether you're looking at gold PFM, you know, full contour zirconia in this case. So we know what we're about to see. So. We look in the mouth and this is what we see. Now, what do you know about full contour zirconia? Jerry spoke to you about it. It's pretty strong, right? It's basically, at the moment, the strongest thing we have other than gold in terms of something that won't break and yet it's broken. So. Question is. We cut it off. Okay. There's a little bit of resin cement there, you know, that was used to bond it on. You can semi bond them on. It's a mixed bag but it was on. So the question is do you look at it is why did it break. What's that? The occlusion is a good reason, and the occlusion is certainly a part of it. These things always break because of the occlusion. So you're right. What else? Yeah. Problem with the preparation, the problem with the preparation, and this might show it better is there's no functional cusp level. Right. So the reason I was sort of. You know, I wouldn't say thrilled, but I was kind of excited and a little bit looking at it when I cut it off is, you know, you can always learn from failures or you'd like to be able to learn from failures. Sometimes you do. Sometimes you look at things and go, I have no idea why this broke, but a lot of times, you know, looking backward, you can figure out why something went wrong. And what was great about this, is it completely validated? You know, one of our most basic things, we start the first day in fixed prosthetics, talking about you have to do proper reduction in the proper positions on a tooth to allow for the material to have proper thickness. Why did this break? There wasn't enough thickness of material right here. This prep looked, you know, kind of square. You know, the tapers on the prep are fine, right? It's, you know, it's quite retentive, but they forgot to take away some here. The material is too thin. The lab either didn't notice it or perhaps didn't want to argue with the dentist. And that's very common. You know, you may have the experience where the lab calls you some time and says, you know, I'm looking at this impression you sent. I tried pouring it. I can't really read the finish line of your prep. I don't know where the margin goes. And a lot of dentists say, you know, what do your best? Yeah. Do your best and it'll be all right. And then they stick something and it doesn't fit. Labs hate that, but a lot of times labs will do whatever you tell them because they don't want to lose you as a client. So it's possible the technician called and said this is going to be a little thin over here in the dentist may have said, I don't care, just build the crown. Or maybe the lab didn't really pay attention. Who knows? But that's why it broke. Which is kind of neat. You know, it's nice to have validation that we do things for a reason and they actually matter. Yeah. Oh, that's a great question. Thank you for asking. A very short time. Yeah. The funny thing was, the patient also showed up with a set of old physical X-rays that were only a couple of few years old, and there was an older Crown PFM that had been replaced by this. So, I don't know. I didn't ask the patient. Was this done in the last year? The last two years? But it was not a long time. So, you know, even with our strongest material there is. I may have told you this story if I did, I apologize. When full conscious zirconia was appearing in the market in the US, there was a big lab in California, and the way they tried to market it is they sent basically every dentist in America. Did I tell you this? They sent every dentist in America a crown and they said, try to break it. So my partner in practice took it out back, took a hammer and started hitting it and it didn't break. Strong, but this broke. Any other thoughts or questions? So it's nice at times to be reminded of why we do think the things we do, and that they actually matter. Okay. Let's see. So what we're going to talk about today. Is going to be a range of, um, kind of things we need to cover. Some of them are going to be very, very relevant to you. Some of them not as much, but we still cover them as basic background stuff. And I'll explain the difference as we go. This is important to us. Today we're going to talk about Pontiac design because we when we do a three unit bridge or a four unit bridge, any kind of span, there's going to be a replacement tooth, which is the Pontiac. Right? That's our term for it. Today in lab, you're going to begin an exercise doing a three unit bridge. Three by five you're going to need to make a Pontiac. Right. As we look at this I'll tell you what design we're going to ask you to make. And when we grade your temporary, we're going to look at whether you make the Pontiac design correctly. So that's going to be one of our topics today. It's talking about this notion what we're looking at here. The reason we have this is there was actually a time a few years back on the CDC exam where they demanded not just a three unit preparation, but a temporary. So they asked at the time, they asked a prospective dentist to prep 19 and 21, and they allowed for either a hygienic pontic, which is what you're looking at here, a sanitary or hygienic pontic, or to make a modified ridge lap. And so what we instructed our students to do here is probably the safer bet of those two is to make the hygienic Pontic. It's a little easier to do and and have it work out. Now you could ask why is the temporary not on the exam anymore? Because it's not. And the reason is around the country, students were failing that part of the exam at such high rates that there was, you know, all but a revolution about it. So they ultimately threw it out. People couldn't couldn't seem to make temps, which is discouraging, isn't it? So this is a hygienic Pontiac. So we're going to start out looking at some diagrams as a good way to see this. So the thing about Pontiac design let me see if this pointer will work for us a little bit. So when you're making a Pontiac, one of our goals, especially towards the front of the mouth, is always going to be if somebody looks at it well, this doesn't really work. If you're looking in, what does a tooth look like. And so looking you know at this there's going to be tissue. And then the tooth grows out of the tissue a natural tooth. So when we make a Pontiac, one of the goals dentists had all along was to figure out how could we design a Pontiac that would fool the eye, that might look. Like a tooth. So there's been different things proposed over the years, and we'll consider them. And what's good or bad about them. Where we're at at the moment is when we have a situation that will allow it, that affords itself to this type of design. What we typically like to make is called an O8 Pontiac. It has a sort of oval or overweight design. The surface of it is this kind of rounded or oval shape. And the way the oval Pontiac goes, if you're looking in cross-section, is it actually indents into the tissue. Right. And by doing that, if it's properly designed, it can fool the eye very, very well. It can really look like a tooth. And one of the first and obvious questions about the ovoid Pontiac would be, well, wait a second. If this is sitting in the tissue, isn't there a big risk that the patient traps food or other plaque or debris under it? That it could be a problem for hygiene? And the answer is actually not if the patient bothers to clean it, because it's sort of this oval shape. If the patient threads some floss, you know, under the connector and just sort of sweeps the floss under there, it should clean out very easily. Right. So the OV design actually is a very kind of healthy design to do in situations where we can do it. Another design we're going to consider is what might be called a bullet Pontiac. And that mostly has to do with how it's shaped. This is essentially, um, in practice, a design that's used to adapt to odd ridge shapes. And we'll look at a diagram of that. An old, old design was the Ridge Lab Pontiac. And this was a situation where, you know, the under surface of the Pontiac rested right on the ridge. So this, again, was created as a way to try to fool the eye. So if a patient's looking in the smiles high enough that it might sort of look like a tooth, right? The problem with the Ridge lab, though, is this is one where food can trap under it. It's not as easily cleansed, able to shape, does not afford itself to that. So this is not a great drawing. We'll look at better ones, but a design that came along later was the modified Ridge Lab. It was actually created by a dentist here in Boston who who taught at Bu in the latter part of his career. And he, um, he designed this idea wear out on the sort of buckle half it rested on the tissue on the lingual half. It opened up. So it went from a kind of con cave shape to a convex shape. And the idea was that when the patient brush their teeth, they could kind of clean under it in that way. So it was a way to try to adapt, try to figure out something that would look esthetic. And yet it was still a healthy and cleansing bowl. So to start with the Bullitt Pontiac. You know, looking from the side, it might look something like this if this was our tissue. But again, what we're trying to see in this diagram, just to illustrate it, is the light line. The smaller line right you could see would be what a tooth might look like before it's ever lost in terms of height and shape. But once the tooth lost you know that typically we're going to have some resorption of tissue and bone. And therefore there's a tendency or risk that if we have a Pontiac that starts to go down all the way to where that ridge is, it starts to look very long. So what's done in this sort of diagram is the idea of trying to make something that looks the right length, if you can see it. But we're never going to really do a bullet Pontic in the front of the mouth. This is always something in the back of the mouth, and so can people see in the back of the mouth. No. Not really. The only people who see in the back of the mouth are patients. And some of them will do this. Some patients, you know, you you put something in the mouth for trying, and they grab their lip and they yank it aside. And, you know, no one's ever going to see it except, you know, you, the dentist, maybe the hygienist, the assistant and the patient when they do that and assuming the patient's not going to walk around. Every person they encounter going, hey, look this. No one will ever see it. Um, so one of the things that I find a good idea, and you may have already done this yourselves in the past, is when you're delivering something or frankly, long before you ever deliver it. When you make a temporary and put it in the mouth, you often want to sort of modify the patient's expectations, sort of get them to think, bless you, think in a real or rational way. So you might say, hey, by the way, way back here, no one's ever going to see this unless you go out of your way to show them. And get them thinking about it reasonably, because the first thing anyone does is really look at it in ways that no one does. Um, I may have said this to you before when I work in the front of the mouth. One of the things I always do with patients, besides handing them the mirror to look. But what does a patient do when you hand them a mirror? They take it and they go like this. Yeah. How often does anybody get in their face like that? And when somebody does, they're probably not looking at their teeth. Right. So they're they're doing this. So one of the things I like to say to patients all the time is, you know, after they get done doing this, they say, you know, you hand me that mirror and I'll stand a couple feet away from them and I'll say, here, I'll hold the mirror. What does it look like to the world? Right. Most of us don't interact with the rest of the world from three inches. We interact with the world from, you know, even when we have a close conversation with somebody, it's a couple feet and that's what they need to to see. So it's often useful to kind of get them thinking about what makes sense as opposed to, you know, what's crazy? So anyways, here's a couple of the diagrams of the bullet Pontiac. Um. This is and this is trying to show how essentially what the bullet point does is it's giving us a kind of rounded oval surface, something that will be cleansed able. Because as Dennis, one of our big goals is to make sure that we don't just put restorations in that are good that day, but that can last. And the way they're going to last is that the patient can clean it. So by making these kind of rounded surfaces, it's easily cleansing even the most basic efforts at flossing and water picking, things like that will clean it. What the diagram is trying to show is, you know, if you have a ridge that's a little altered in shape because of how the tooth was lost, you know, you can just make it sort of lay against the tissue however you'd like by having things sort of lay against tissue, you try to prevent things from trapping underneath too easily. By having a rounded shape, you make something cleansing. And so this is just a couple of diagrams of that notion. This is a better diagram of what a modified ridge lap Pontiac looks like in cross section. So the buckle half of it rests on the ridge. The lingual half opens up to be able. Yeah, yeah, this was designed in Boston. It was designed by a guy named Bob Stein. He's deceased now, but he. He practiced in Boston. He taught at Tufts a long time, and then he taught it, bu for a very long time. Um, uh, but he he he invented this, um, he was a, you know, terrific teacher at. I was doing prostitutes, one of our teachers. But anyways, I mentioned it mostly, you know, because. But anyways, he designed this as a way to try to manage the problems with the Ridge Lab poncho, because that's what they had before that. So, you know, that was very clever. The challenge is these do have limitations, both esthetically and functionally for cleaning them. But it was it was a good idea at the time. Um, now take a good look at this. And the reason you want to take a very good look at this is that on your final summative exam, we're going to ask you to do this. So we're going to ask you to make a modified Ridge lab because on your patient we can't really make an oval stick. So we're going to ask you to make a modified Ridge lab. So on the temp on your Pontiac, the buckle half is going to kind of rest on the tissue. You're going to open it up kind of like this on the lingual. Right. In today's demo, I'll try to show you how you shape that. It's very easy to do, you know, we'll talk about what's involved in these steps. Here's a couple other diagrams of these things. You know the idea part of it rests on the tissue. Part of it opens up. And that's the idea of the modified ridge lap. And it's still very, very commonly used. And the reason for that is that not every situation you encounter will work for innervate Pontic or, you know, may afford itself to that option now. This is the whole notion. We're always trying to make something look natural, especially in the front of the mouth. And so this goes back to that idea we were talking about before. In the thin Line, we're looking at what would have been the tissue originally the shape of the tooth originally. But when this tooth is lost, we're going to have some resorption and change in the ridge shape. If we built our Pontiac with the same contours the original tooth had, it would look too long. So the diagram is trying to show, well, you know, tuck it in a little bit. Now it looks shorter. It might fool the eye. This is something for you and your lab tech to work on. In these cases, when you find yourself doing this type of pantech. Here's another diagram trying to show the same thing. If we follow the original tooth contours, it would look too long as opposed to what would be a natural length. You're always looking at the neighboring teeth to make something that conforms to the patient's, uh, you know, normal appearance. Um, so that's our basic outline of Pontiac design. We're going to look at a bunch of clinical examples in a bit. But next, what we want to talk about for a bit are the frameworks of our bridge the substructure of our bridge. Now you might remember early in the class we talked about this stuff a little bit. We talked about flexure, how as a bridge gets, you know, every increase in length, if it doubles in length or triples in length, how that changes the relative flexure, you remember that occurred as a cube of whatever changes there were. So something twice as long flexed eight times as much, something three times as long, flexed 27 times as much at the same time. We talked about this earlier in the course. One of the things I said to you is that this becomes increasingly irrelevant. I haven't done a really long span bridge in a very, very long time. I talk patients out of those things instead to have dental implants and make either simple restorations or short span bridges, you know better to put in a couple implants and make a three unit bridge than a five unit, right? So that's changing. And the more patients are comfortable with the idea of implants, the more predictable they are, the more. I wouldn't say affordable implants are not an inexpensive treatment modality, but the more patients hopefully can afford these things, the more often you're going to do those as opposed to a long span bridge. So when we're going to make these our key thing you might recall we talked about this before is it's not just a function of how tall this is. What really is going to determine the flexor is frankly, going to be how tall are our connectors. Because the thinner the connector is, the more likely something is going to be to flex as it flexes. It puts stress on this. It puts stress. Then, you know, tension on our abutment teeth. On our actual retainer crowns. You know, everything about it is more subject to loosening up, decaying, fracturing, everything. You know, the longer it gets. And so the more we can have height in our connectors and shorter spans, the better off we're going to be. So when we make our connectors, our goal is going to be twofold. One, we want them as tall as they can be while still allowing a proper brazier form. Because if you have a connector that goes too far down, you don't have a proper embracer, which is going to be very unhealthy for the tissue. If you make it unhealthy for the tissue, it really doesn't matter how strong the bridge is. If the teeth develop periodontal problems and you lose the abutment teeth, right? So you have to make things that have proper contours to maintain proper health. You want to have as much height as you can, as much width as you can, again while maintaining proper embracer form. And in doing those things, you try to create adequate strength and that's your objective. The other thing you like to do with your connectors, and you can see this here in cross section, is you like them to be kind of rounded. You like them to be smooth. You don't want things that are shaped that are going to by their very shape and nature, trap, a lot of plaque or other debris. You want something that's going to be easily cleansing for the patient. Now here's something kind of interesting. We looked at a broken full contour zirconia crown at the start of lab. Well, here is a fractured six unit full contour zirconia bridge. Again. Do these things break? Well, obviously they do. We see one. But you don't see these break a lot. Right. And if you look at this, notice how tall these connectors are. Right. This doesn't look like something that should break. And yet the patient broke it. Um, this patient, for what it's worth. You know, as I said at the beginning of the, um, day, you learn from things that break, you know, you look at and go, alright, what happened here? I don't think there was anything wrong with the design of the bridge, per se. What happened here was a problem, um, frankly, of the patient. Which I didn't get to choose, he showed up. The problem with the patient is he is just a horrific cleanser and grinder. He I mean, you know, he puts his teeth together and he and, you know, you can just see things rocking around in his mouth. He's a monster. What's that? Oh, no, he wasn't a football player. He's not that big, but he's big enough. Yeah. Hockey player. Wrestler. Yeah. He's he's just. And he's a really nice guy. You know we love we. Well we kind of love having him come in. But not when he breaks things. You know he's fun. He's a fun he fun guy. He's a character. But he he he clenches and grinds and he broke this. So what we ended up doing actually, interestingly enough, is we remade it as porcelain fuzed metal. Now, in theory, full quantum zirconia is so strong, that might be all right. But there's a difference between metal and ceramics. What would be the big difference between metal and ceramic? Flexibility. You know, metal is going to have a little more ability to flex. And so what I was I wouldn't say gambling on, but my thinking in remaking it the other way is that if he's going to clench and grind. That the metal will handle it better. And so far that's been in his mouth a number of years, and he hasn't broken it again, as far as I'm aware. Um, but, you know, that's that's the story. Speaking of of, um, as far as I'm aware and and breaking it, this is a story you might enjoy. So it's Yankee Dental this weekend. I hope you guys have plans to go. I hope so tonight to the thing at the B reception and maybe, maybe tomorrow to to walk around or see some lectures and stuff. It's I mean it's actually kind of fun to go there. But anyways, one of the things that we used to always do and in fact, I'm doing it tonight, I'm going to meet some of my old classmates. We're gonna have dinner, right? You know, and when I say my old classmates, they are old now, so I'm going to meet them for dinner. But one of the things you guys will do when you first get out of school, you'll go to Yankee. It's sort of fun. Hopefully weather. Even if you're not in the area. Maybe you'll come back to Boston to go to Yankee, hang out with some of your old friends. So we're out of school, uh, for about a two years, and a bunch of us meet up at Yankee, we go out to dinner, and so, of course, we do what Dennis do. We start talking about dentistry, right? Um. My wife, my wife, um, probably thinks Dennis the most boring people on earth, but she's usually too kind to say that. Uh, but when Dennis get together, they start to talk dentistry. So there we are. Myself and some of my classmates, and we're talking about stuff. And some of our, um, you know, dentists like to tell, um, war stories, right? If you know the phrase you tell about things that happen in the office, stuff you experienced. So I tell a story of something really stupid I'd done. Right. And I'll share this with you because you could learn from this. I had an old, old, old guy show up in the office. He had a denture that he'd had for like 30 or 40 years. And, you know, he's sitting there saying it's kind of loose. Is there anything we can do with it? And this is a long time ago. We weren't going to put in implants at the time. And he was too old. He went to have agreed. So I was young and therefore by definition, stupid. And I said to him, well, we could make you a new one, or we could rely on the old one. Now that's stupid. If somebody has a denture, right, that's 30 or 40 years old and they ask you if you can make it tighter, you can make them a new one, but don't touch the old one. Because when the new one is uncomfortable, they can always wear the old one. But if you take their old one and you're as stupid as I was at the time, and you realign it, now, you put it in their mouth and you go, look, it fits tighter. And then the patient calls you the next day and goes, well, it kind of feels uncomfortable. So you get them in and you do adjustments, and then they call you the next day or the day after. It still feels uncomfortable, but you can't go back, right? It no longer fits the way it did because you rely on it, and now it's your problem and you own it. So this old guy was calling us constantly, and we were seeing him a couple of times a week. You know, week after week after week. And if any of you have experienced this in your practices in the past, it's pretty annoying. You can imagine. Um, I always think of these sort of patients as going through those stages of grief. If you've read about that, when people die and at first you're it's tragedy and you're angry, you go through different stages of grief, and eventually you reach that stage of acceptance that happens with these kind of patients. You see them over and over again and you're like, like you see that? Oh, they called. SPEAKER 1 You know. SPEAKER 0 And then you know, and then you're kind of angry at them. You're depressed about it, all kinds of things, and eventually you accept it. It's just a part of every day I'm going to see, you know, Mr. Smith, he's going to come in. Oh, how are you doing today? Yeah, yeah. SPEAKER 2 Oh, well. SPEAKER 0 You had yogurt for breakfast. Good for you, you know, and you have a nice conversation, and they become like a, like a part of the background noise of your life, and it's okay. So, so we're seeing a month after month. And the solution to these things that, that I've adopted, and I don't know if this is the right choice is you basically just wait them out. You just keep doing it and eventually they lose interest and move on to other things. Or maybe you get it comfortable. Finally. So we see them over and over again. I'm telling my friends about this and they're all nodding because, you know, they're learning something not to do what I had done. And one of my friends said, you know, I had a case just like that. I made some dentures for a patient. And I was seeing him, you know, like twice a week, week after week, month after month. And then he died. Said. Good case. So yeah. Like, exactly when he. Once he died. Once he died, it was a good case. So. But the problem. So the problem is they're not all going to just do that, do you? That favor and die for you. So sometimes you're stuck with them. Yeah. You guys asking about, you know, how long this had lasted made me think of that. But I'm pretty sure he's still alive anyways. But there's there are lessons in these things. You know, you learn from the things you screw up. You have to pay attention to try not to do them again. All right. So talking about zirconia and connectors right. There are recommendations for connector size. So you remember when Jerry spoke to you about this. He said there's you know like the sort of older version, the more opaque zirconia it's stronger than the newer translucent zirconia. So these recommendations came come from Norwalk. And they make one of the better or at least more predictable. Zirconia is out there. They're a great company. You may be familiar with their other stuff, the Norwalk, um, um, kind of China, you know, that you might eat on, but they make wonderful stuff. So these are their recommendations in terms of sizes. These recommendations are like a year or so old. So they may evolve over time. But this just gives you an idea. And if you look at this you can start to see you actually need fairly big connectors. You need a lot of, you know, height and width for these things, even with stuff like zirconia. So it's worth looking at it in terms of iMacs, which is another popular material, one we often use. You're familiar with that. You know, in the front of the mouth you need a pretty big connector. In the back of the mouth, they would say, don't do Emacs. There are people who do. But I would say you're looking for the risk of it breaking too easily. All right. Oops, I went backwards. Sorry. All right. Now we're going to look at a few things that are kind of older for a second and in some ways relevant more just for what they illustrate than something we're going to do at the moment. Because one of the things in the past, when we were doing everything as pawson fuzed to metal, you know, you would find ways to, to make them work better. When we get into things like full conscious zirconia, this becomes irrelevant because the material is is full contour. But when we had substructures, one of the ways we would try to make these connectors taller and therefore, um, less, you know, flexing, you know, less flexure as the patient would eat is you'd create these sort of struts, you would, you know, modify the shape. Um, it's worth looking at just to sort of see what was done, how you would manage these things. Here's another example of porcelain fuzed metal. Here's a bridge. This is on the model. And you can see it's designed to try to create proper and brazier forms, and yet also maximize the height of the connectors in metal, because that's where our strength is. Now, you guys, are you still taking partial denture design or are you done with it? Oh, you're still in it. You're still doing it. And have you learned things? Yeah. Okay, so we'll find out. We'll find out. So looking at what you see here. Do you see anything that Doctor Schnell would object to? Or do you? Or would she approve? So what kind of class do they have to put on there that would make Doctor Snell happy? Could they put an RPI in this? No. So what would you have to do here that would make her happy? Well, you could do that, right? Rebuild the thing and put the rest over here. What else could you do? What was she to the alternative? Her combo combo class. Right? With the why or arm? I don't know, you know. Is that deep enough for the wire arm? Maybe. So. Maybe they designed it, right? Over here. It looks like they're going to put a C-Class back here, doesn't it? And this. So this doesn't look like a kind of design she'd like very well. Uh, what are you going to do right now? Here. Here. What do we have for our Pontiacs? These are kind of a modified Ridge lab. Basically, because the ridge is so thin that even though this kind of sits on there, it's essentially a ridge, a modified ridge lap in terms of how it's going to function. So here's a few clinical other sort of clinical examples of things. This is a hygienic project. This is that patient we looked at when we were talking about alternative temptation. And we taken this bridge and realigned it. This is here. It's a hygienic Pontiac. It sits way up off the tissue. Do we do these very often? No. You know, it's a it seems like an odd thing. And for the most part, if you're not doing full gold like this, you might worry about the strength of it. So it might not be a good choice. And even if you're doing it in full gold, a lot of patients may not like it. It's sort of an odd design. Every time they eat, it seems sort of likely food might go under there. Now, some patients might like that they're carrying around a snack for later in the day. Other patients. Might like it because it's actually easily cleansed. It's a very easy thing to clean. Even if there's a gob of food stuck under there, they can probably just poke it with the side of their tongue and clean it out. Right? Or they could take a little toothpick or whatever. Very easy to clean. But if you're ever thinking of this sort of design, if you ever find yourself considering it, what you have to do. This is one of those things of doing smart things. You have to make sure the temporary is shaped the same as the projected pancake. Make sure they like it. Don't just make it and stick it in their mouth because if they don't like it, you're back to square one. So that patient. This is the same case the that was taken off because it was failing. You saw in the past how we use that to make a temporary. And then we were going to make, um, porcelain fuzed to metal. This is some years ago. We're making portions fuzed to metal. And what we're going to make is a modified Ridge Lab design. So this is the metal substructure. There's a couple of things worth talking about here. You notice we have metal collars on the buckle. It's so far back in the patient's mouth you can't see it unless you go out of your way to look. And you might have noticed on the previous image that she already has a gold inlay in front of it. So the look of it isn't going to matter. She's comfortable with this. You'll see. This is going to be designed this part to rest on the tissue and then open up here. And then there's going to be porcelain coming here. So here that's tried in in the mouth. Make sure it fits right. Um, when you're trying in things like a bridge, might as well talk about it at this very moment. We're going to talk about it more in a little bit. When we talk about soldering things you try in a bridge and you've done this in the past. But for anyone who doesn't recall or didn't do it, you see it if it's in one piece. And to make sure that it the first thing you look for, let's say maybe not everything, the first thing you look for is you press on one end and the other and you see, does it rock? And you can tell if they rock very, very easily because as long as the patient has some saliva, if it rocks, it starts to bubble along the edges. You get some percolation on the edges. You can see that you know right away that it rocks and that you're going to need. To either adjust it till it seats, which sometimes can be done, or you may end up having to cut it and solder it if its portion fuzed to metal, and if it was full conscious zirconia, you might have to remake the whole thing. But that's what we're going to look at. And we'll talk about that more in a little bit in the next chunk of material that we have to do. So then we goes back to the lab. Porcelain is applied on it. So this is PFM. We're going to bring it back to the mouth. You can see we stayed above the tissue. There's metal collars present. And it's inserted. It's a modified ridge lap on this side. It's that ridge lap portion on this side. It opens up to be somewhat cleansed. Well, the other thing to notice about it, for what it's worth, is if you look at this, just sort of the basic appearance of the porcelain. Personally, I think it's it's a very esthetic porcelain. It comes out nicely. The reason I want to mention that to you is there is that tendency we have in dentistry, where every time a new material comes, you assume that all the old ones are no good anymore. And we've tried to say there are times where Pawson fuzed to metal, you know, in terms of a patient looking in and seeing this, this is going to look very, very natural. A good technician with these materials can make beautiful, beautiful crowns. So. Conceptually, while it might be easier to work with all ceramic materials, not having a need to hide metal. You can still make. Beautiful restorations with materials like Pawson fuzed to metal. It's really up to the technician and the dentist. Here's another circumstance. This has failed. You can see there's been all kinds of things that have happened here. A bridge was done. This is a modified Ridge lab. This is an old case. Um, we looked at something like this previously. You might recall we talked about it before. Where? You know, if I was doing this now, what would I try to have done? I would, I would try to graph the tissue or bone. You know, if we were doing this now, even if we were going to do the bridge, we would probably try to improve that and maybe make something more esthetic. Fortunately, this is with the lips retracted, not the patients smile so it looks okay in the mouth, but we would probably do it a little differently. Yes. This. Why have we left the collar? Oh, yeah. I'm glad you asked. Um, thanks. Thank you. Because you know what, ump? No, no, not be sorry. It's good. It's always better to ask because there's always other people thinking the same thing and didn't ask. Um, the reason we did that is just as a reminder, the original thing had been kind of an online bridge, so it was way away from the tissue. So as we're making this, because it's not going to show we stayed away from the tissue just a bit easily cleansed. Bill. So, you know, this goes back to what we talked about early on. Where do we put our finish lines. If you can stay super gingival stay super gingival all right. Now years ago when we were doing porcelain fuzed to metal it was harder to stay super gingival because some patients you know if she didn't have this here say this is a natural tooth. And I say to her, um, we're going to make a bridge. And I'm recommending that we keep the edge of it a little away from the gums so it's healthier, easier for you to clean everything about it better from a functional perspective. But the one thing you need to know is if you take your cheek and you pull it aside and you look down there, you might see a dark line. Some patients. Most patients would say, okay, that makes sense. Nobody can see it. Who cares? But there are some patients. Who might say, oh no, no no, no, no, no, I can't have that. Just knowing just knowing that it's there is more than I can bear. I won't be able to sleep again. And you think I'm making a joke? But we've I've had patients who are like that. They go crazy over the idea that you might ever, you know, so everyone's different. You know, some people are you know, we would look, we're all we're not nuts. All of us, right? We're dentists. We're rational people. So, you know, we would say, oh, yeah, keep it away from the tissue. I just want I want a brush. Keep it healthy. I don't want to remake it too often. I don't want the the gum tissue to be inflamed. I don't want to lose bone around the tooth. I want function, especially in that part of the mouth. But patients, who knows what they're thinking? All kinds of stuff. Yeah. Uh oh in terms of easier adaptation than person. Yeah. I mean, it's a good question. The question is, would the the the, you know, would it adapt better using metal? I mean, certainly as Jerry talked to you about, you know, some of these techniques do work better. You know, he he described like to think of it in a related way. He described to you with Emacs, you know, you can mill it. Or you can press it. Now, in theory, if the milling machine is really good, it'll fit just as well. In practice if he does a lost wax technique and presses it. It's probably better, right? Same as like you make a gold crown, you know, in that technique or, you know, they make a wedding ring for you in that technique. It's the same thing. So, um, so in that respect, yeah, you know, you can make a arguably a beautifully fitted restoration. So yeah, I mean it's not it's a good reason. The biggest thing to me always with these is if you're a little above the tissue, right from the patient perspective. And I'm repeating things. The most cursory efforts at brushing their teeth, they're going to keep it clean, which is going to make it last longer. But from your perspective, is the dentist. If you're a little away from the tissue when you're visualizing the preparation, you can make a better finish line because you can actually see it. You know you're wearing your loops. You can see it's better than if it's buried away under the tissue. And you're like, well, it kind of feels okay, but I have no idea what's going on down there, right? Now you might like to fool yourself, in which case bury things deep under the tissue and you can pretend that it's all accurate, but it's harder to know. Whereas if you stay here, you can see it when the crown comes, when we, you know, when the frame came back and we tried it in, you could see it. Right. When you cement it, you can see it. When you clean the cement, you can see it. You can make sure that it all really fits. When you go to make an impression or a scan, it's easier. It works better. There's no downside for you as the dentist to do something that's going to work more easily for you to achieve an ideal result. So when you can say super gingival, I mean, that's part of why dentist so much love all ceramic materials. All of a sudden we go, yeah, I'm not worried about this. I'll do the full contour zirconia. There's no metal to show. It's not a problem. Now, you still might want to tell the patient. Even if this was, say, all ceramic, you might want to tell him if I stay slightly super gingival, you might see along the gum line the tooth which could be a little different color. So they might still see something that to them as a dark line you need to make sure they understand that. But it's a lot easier than worrying about hiding a black line of metal. All right, so we'll go. We were looking at this guy. All right. So here's the thing where, you know we're going to look at something else for a second. We don't really do much with the Maryland Bridge anymore. In our course there was years ago. We used to do designs and you'd make preps, but we kind of ran out of time for that. This is a traditional looking Maryland bridge, but we're going to make a modified bridge lab for it. Okay. So one thing I do want you to see here, if you're ever using a metal Maryland bridge, which is not really what I do anymore, but some people still do. Notice here. We brought this back and the wings on it are covering most of the lingual. And because of that, notice where the enamel is. You can see where the tooth is translucent. We see the metal. That's a problem right? But not really, because when we bring it back, you know, with all this, what we're going to do then is in the patient. Well, while the patients, they're not directly on the tooth, but we're going to take it out. We're going to reshape it, try it back in and out. Till when we look at it, we no longer see the metal. So what we're doing with this as a step by step approach is we're maximizing how much coverage we're getting and therefore how much bonding will surface. We'll have while having the esthetics we want. With this particular situation. So there it's going to go back to the lab course and applied. It's ultimately cemented. But the design, for what it's worth, was a modified Ridge Lab. Nowadays, if I'm going to do a Maryland bridge, a bonded bridge, I'm going to typically use Emacs. And this is a very common application. You know, you're all we talked about this before with that patient we looked at a few weeks ago who had been congenitally missing her laterals, and an orthodontist pulled the canines over. You know, nowadays we'd ask the orthodontist to keep the canines where they belong. And then after the author is completed, what we might like to do is bond in a couple of Maryland bridges. The patient's too young to have implants. So we bond these in. Okay. Now the thing to notice here this is at the time of insertion. So you know how you keep the patient's mouth open for a while. The teeth are going to get chalky looking. Every patient's different. Some people they can sit there with a mouth open for an hour and you don't see anything. There are other patients where you pull their lip back and two minutes later their teeth start to look chalky. This patient showed a lot of hypo calcification. You notice the lower teeth look very different. So as soon as these rehydrate, the color is going to look fine. But it's bad at the moment. But the design we do with these things typically is just with a single wing now. Okay. The problem with the Maryland bridge that we found is that there would be that tendency to d bond on one side, and then it was kind of a disaster. You had to somehow knock it out of the mouth, clean it all up and try to re bond it. And they never worked as well the second try. So these are bonded on one wing here you know. And a Pontiac one wing and a Pontiac. The design of the underside of these is essentially a modified Ridge lab though, because we're not doing anything to the tissue to modify it. It's just how it comes back from the orthodontist. Um. And as long as the occlusion allows this little bit of a cantilever, it works fine. So this is sort of how we'll do a Maryland bridge nowadays, especially in those circumstances. Now here's going to be an example of an old Pontiac. Obviously, you can't see it in the patient's smile, but once we pull the lip back, we have an overweight Pontic up here, right? And if we look, there's more going on than just that, right? This is a you know, you can mix and match. So in this case the patient had this canine that was pretty intact. I mean obviously there's this abrasion here but the tooth is pretty intact. We don't want to crown it. The patient wanted a bridge as opposed to an implant. So what was done then was to crown this tooth. We have a Pontic here. An overweight Pontic. So it looks, you know, pretty natural in the tissue. And then we've bonded a wing there to support the other end. Now here's another example of an overweight Pontiac. To look at, there's the temporary in the mouth. And if you look at this, it really looks quite a lot like a tooth I think the temporary. When we remove the temp, you can see the tissue is formed into what looks like a fairly natural architecture. We have Pontiacs. Even I'm not. Excuse me, not Pontiacs, but we have the pillars present. Looks pretty good. This is at the moment of insertion of the regular bridge. You know, it looks quite natural. That's what the Pontiac can do for you. Here's something sort of interesting. When you look at this, it's blown up pretty big. This looks like a Pontiac, doesn't it? Trying to see that that's not growing out of the tissue. So we have we have, um, you know, like a modified Ridge lab there. Anything else we see here? Okay. You guys are very, very picky. I give you credit. But there's a there's a weird illusion. There's something very strange going on here. That's an overweight Pontiac. And when the temps out of the mouth. That looks enormously weird, doesn't it? Why would somebody. Have an overweight Pontiac next to a modified Ridge Lab. It seems bizarre, doesn't it? What kind of dentist would do something this bizarre? Well, I did it. Um, but there's a reason it's like this. The patient had had an existing six unit bridge. Right? But under that bridge, number nine failed. Eight had been a replacement tooth going back a long, long time. So it needed to be remade. So eight was extracted and innovate. Pontiac was created. And I said to the patient, well, here's what we need to do. We want to reconfigure this tissue to make two a side by side so it looks as ideal as it can. And the patient said no. You wouldn't let me. So if I can't, it isn't like you can tie the patient to the chair and and, you know, hack at their mouth despite them telling you not to. You know, that's assault. There's laws against that. So she said. I know, stupid law, right? Um, so she didn't. She said no. So we couldn't do that. So we made an overnight Pontiac here. Against the modified Ridge Lab. It's bizarre and odd, but that's but the most interesting thing about it. If you look here, you can very well see the difference. This looks like a tooth coming out of the tissue, doesn't it? This does not. So that's the difference of what a Nova Pontiac can kind of do for you. Yes. Why did you. I have no idea. It's a good question. What was asked up here is why did she refuse? And I don't know. She wouldn't. She wouldn't let us do it. Well, the opioids are easy to clean. You just, you know, the old Pontiac, you just sweep your floss in it. For whatever reason, she said no. And so we said, all right, you know, what can you do? Um, you know, there's that saying you can lead a horse to water, but you can't make him drink. So you can you can tell her all the things you can explain. You can show her. And she was happy. No. So we couldn't do it. So here's an example of creating an overweight Pontiac. So you can see how that this is done. So the patient had this tooth it fractured right. So it had to be removed. And you can see it had an old power post in there. Part of why the tooth fractured was there was a post in it. When we talk about restoring endogenously treated teeth, we're going to spend a lot of time me saying to you, don't put posts in teeth unless you have to. Only only ever put a post in if you must. And we'll talk about that a lot when the time comes, because post fracture teeth. So the tooth split in half. It's been removed. And so here is the extraction site. At the time it was removed, um, there was an old, uh, set of crowns here. And we're going to temper, you know, we're going to temper this so we start a temp. This was done in a matrix, kind of using the shape of her old crowns to work with. When you first do this, realign, obviously this doesn't look right because, you know the socket is collapsing. It makes a mess. So what you do then? As you use your salt and pepper technique as you know how to do, and you shape this into what you want the underside of your ovoid pontic to look like, you polish it real well, as you can see, and then you cement it. So this is put in at the time of the extraction and insertion of this temporary. And you can see the occlusions a little weird. Her occlusal plane is strange. It's just how it is in her mouth. So here it is. This is at the time of insertion. This is chipped in the past. It's been patched. She's happy with it. Um, one of those rules is if the patient is happy with it, you know, I think as a smart thing, as you don't force them to to do things they don't want. Because as soon as you force her to redo this, if she's not happy now, you know you are a bad guy. So that's at the time of insertion. All right. We wait two months and it's healed. What else do we see? Like everybody, she doesn't brush your teeth, right? You know, if if brushing your teeth, if caring for your mouth was sort of the measure of a person. There's a lot of horrible people out there. This is if this if if if how dentists judged people with strictly whether they brush their teeth. We would think all our patients were were like the worst people in the world because they don't brush their teeth, you know, why would they? So here she comes back, all this plaque. But you can see this is healed up when we pull this out. This is what it looks like, right. What you'll find under these is that if if she brushed better, this little red spot wouldn't even be there. It would be healed beautifully. So these heal up beautifully. They're very maintainable. They work great. So then here's the bridge at the time of insertion. All right. This looks pretty natural. Over look. Pretty natural. Yes. Right. You just the lab copies what you had. Well, they just just floss. You thread a piece of floss here, and you slide it under that and it'll slide right over it. Right. And and in theory, it'll clean right out. I'm not doing a modified build up. I set up an overweight. You see, as soon as we did this, the day of extraction, as soon as we made this shape, and you see this and this is pushed into that space. Now, the other nice thing about doing this, this sort of way is it's like sticking a bandage in the extraction site. Right. So whatever bleeding was going to happen now I've kind of plugged it. The bleeding stops and it heals. You have to wait a couple of months. It takes time to heal. But a couple months later you bring them back and you have this. And now you can see she don't brush your teeth. But we're going to, you know, prep these and, you know, finalize the preps, get a final impression. We'll capture this in the final impression. The lab will copy the shape you put it in, and you have a nice restoration. So that now you can see she has a weird kind of bite and all that in her partials, but that's what she looked like at insertion. All right. Here's just another example of a kind of this is more or less functioning as a modified Ridge lab, using some pink porcelain to substitute for a lot of lost tissue. So as it goes in the mouth, it can, you know, work pretty well for this bridge. Now, uh, quickly, um, here's a couple other things that we'll go look at. This is using some of the things we've looked at and adapting a little bit to other things. This patient presents like this. She's not happy with this restoration. Is she right to be unhappy? Yeah. She's not wrong. She had an implant placed. Dentist restored it, and it looked like this. She wasn't happy. What's that? No. Nice work. Right? Yeah. Hopefully he wasn't too proud of it. Um, here's what happened. So? So then what happened is the periodontist who had placed the implant. The patient goes back to the periodontist and says, I'm really unhappy. The dentist did this, and I asked the dentist about it, and the dentist said, no, this is how it's supposed to be. Now the patient's unhappy. So then the periodontist, you know, refers to, in this case to me to deal with it. So what we did is we looked at it and I said, the problem is that the implant and this was done a while ago. The implant is located here a little bit to the lingual. Right. That's what happened. And so the dentist restored it there. But that isn't what the tooth should look like. So then the question is how do we make something that looks like a tooth here. So I had the periodontist re contour this tissue and made room. So I could create a temporary that look like this. I needed space for the temporary to go for the tooth to go. All right. This is actually using the same thing you've done the last couple of weeks. This is a polycarbonate crown form. It's easy. It's quick. Right. It's realign there. And then we made a crown. And what we did actually in making the crown is this is where it sits on the abutment that the previous dentist had used. And it essentially is a little bit of a ridge lap hanging down over the tissue. Ceramic. Now. The patient can, you know, slide a little floss under here and sweep it out. And she's had it for decades now. It's worked perfectly well. Okay. And that's it in the mouth. And ultimately, we made a new crown here eventually. Yeah. I'm sorry, I. Well that's what. Well what was? Yes and no. I mean, it depends what you're asking about when you say UCLA abutment. So, um. I believe I don't I don't recall whether it was a stock abutment or whether they used a UCLA that they waxed into a custom abutment, but it was a cemented restoration that had been made for the patient. When you ask about UCLA, you're talking about the idea of a screw retained restoration or something that's waxed to. A custom about me. That's what you're asking? Yeah, yeah. In this case, what happened is the implant was located because that's where the the bone was. You know, there was bone a little bit to the lingual aspect and that's where the dentist placed the implant. Now, in theory, in 2024, the dentist might have tried to graft some bone wide in the ridge so they could more ideally place the implant. But when this was done some years ago, and this was a long time ago, it's probably 20 years ago, maybe more. When the dentist did this, he this is where there was bone. So that's where he put the implant. And the dentist restoring it didn't really look at and go, all right, what do I need to do here to make something that looks like a tooth? Um, I don't it may have been using a UCLA abutment that they waxed into a custom abutment. I just don't recall what it was under there. I mean, we might be able to see. Yeah. We just used the old one. Yeah. So this is the old abutment. And looking at it, I. I just don't recall. It could have been a stock abutment, but I think it might have been a custom abutment they'd made. So essentially what I, what I did there was just to try to make room in the tissue for, you know, like a tooth to go. That's what we did. It was just a way to manage it. The reason I'm showing you this isn't it's really just to sort of see the idea of adapting a ridge lap as a design to get length and shape as needed. You know. So, uh, the final thing with, with this set of slides, let's look at this for a second. Here's another thing that comes along. Here's a patient, uh, an interesting kind of patient. He, um, he has what we might describe as a long term provisional restoration. This is plastic. It's sitting on a bunch of implants. He's had a couple of new implants added. Let me explain what's going on here. Because you might say, why would somebody have a long term plastic restoration on their implants? The reason this was the way it was is he had a series of implants placed, and a dentist restored him in person fuzed to metal. This was quite a lot of years ago. And then what happened is. The implants sort of died. He destroyed them. And the way he did this is, um, he's he's not huge, but he's solid. So, you know, there's these kind of middle aged men that are just really solid, right? Because we have one. So they're the kind of guy where a lot of people, you walk up and you tap them on the shoulder and they and they, they feel like a human being. Then there's other people, and you walk up and you say, you tap on the shoulder and it's like hitting a wall right there. Just this guy is was a really solid guy. And what he did is he clenched and ground. And when you talk about occlusion and how forces people apply, this guy applied a lot of force. So he destroyed this restoration the dentist had made. And then. So the periodontist placed a bunch of new implants. And then the dentist did something really smart. She moved out of the area. So you. So the dentist is gone. She's left the area. So now it's not her problem. And then the periodontist, we needed to come up with something. And what we tried is we put in a temporary plastic, you know, acrylic provisional. And we found that he didn't destroy the implants as quickly, that it seemed as if the plastic being softer. He didn't apply quite the same force slamming his teeth together to destroy, you know, loosen up and kill implants as he did with the PFM. So what happened over many years is every now and again, implants would die and the periodontist would add new ones. But we were able to kind of keep him in a fixed restoration that was plastic. So that's what happened with this guy. So here we are with this here's a couple new implants. And what I want you to see here is we're going to make a couple of custom abutments, UCLA, uh, custom abutments. And, um, we're going to adapt the idea of a little bit of a ridge lab. Frankly, this cantilevers a little bit as a way to continue using his provisional. You know, this isn't a spot where the the periodontist could graft and get the enough bone out here to place an implant. So they placed it where they could. This is just a little suck down shell that the technician could use to figure out how to contour the custom abutment, and this is what it looks like. This is all polished. This is under surfaces polished, so it's easy for the patient to clean when he Flosses bless you. He can floss very easily and clean that so that goes put in the mouth a couple new custom abutments. They're realigned and he's able to go on functioning. So that's that. Um, any questions before we do something else for a moment? All right. Let's do this. Let's do attendance. Huh? What's that? No, you can ask. SPEAKER 3 No, I just want to know why. SPEAKER 0 Oh the CDK. Um, basically, the failure rate on the temporary part of it was unbelievably high. Everyone failed on the temporary. Yeah. So we actually, for what it's worth, at Bu, we came up with a workaround and our students were passing it. It wasn't a problem for us, but what we did is something very artificial. It had nothing to do with what you would do in a real clinical situation. We use this kind of instant dye material, uh, polyvinyl material. So we'd have our students make a quick alginate of their, uh, preps. Squirt this in there, you know, and like two minutes later you'd have this, like, kind of instant dye. And then you could take your matrix and build your temp on that outside the mouth and then go back to the mouth and adjust your occlusion. So we had a we this was I don't know if you guys knew Doctor Kong. You know Doctor Noah, he was involved. No, actually he wasn't. It wasn't Doctor Noah. It was, uh, Doctor Kong and Doctor um, Hashem. Did you know Doctor Hashem? And presto! So the two of them came up with this sort of workaround, and we. So we taught the students how to do something you would never, ever do clinically. It was stupid. I mean, it was it was just education for no reason, you know, like learn a technique that was irrelevant, but it was a way to pass the exam. It was teaching the exam. So we did all right. But at other schools where they didn't come up with this clever workaround, their students like, you know, they'd have like 75% failed attempt. So it was a problem. So ultimately, after all the complaining, the board threw it out because if nobody could pass it, it was a you know, it was a problem. Everybody set with this? Okay. You guys get this now. A little forward. SPEAKER 3 Yeah. SPEAKER 0 Well, it wasn't what you want to do, but it was kind of a no choice. So will he really kill the implant? Eventually? He probably will. Yeah, because you don't really want to cantilever off, especially in his case. But there's no choice. It was either you do that or he has no tooth there. So it was sort of a compromise. You do a lot of stuff in dentistry. That's a compromise. Yeah. For. In terms of like whether the teeth are too long or something when you're. Well, I guess you, I guess like where you saw the pink porcelain on that one case real quick. You do stuff like that at times if you have to. You know, ultimately you want the teeth to look right in the smile. And if there's just too much space, you use stuff like, uh, tissue colored ceramics. SPEAKER 3 Uh. The area. SPEAKER 0 I yeah, I do the over whenever I can if, if I'm doing that because it's more esthetic and it's easily to cleanse the bowl. But you can't always do it because if somebody has an old bridge and the ridge is a normal ridge, you can say, is it alright if I take a burr or a, um, or a laser and cut away the tissue and make a new thing? Some say yes, some say no. SPEAKER 3 Yeah. SPEAKER 0 Or you can essentially do a surgery where you reshape the ridge and then you modify the temp to fit. That's what you have to do. All right guys, everyone set with this. We're going to move on. All right. All right. Okay. All right, everybody. SPEAKER 3 Let's cut. Guys. SPEAKER 0 We're going to go on because we got to get this done today. We only have so much time. All right. Now this material. Now. In theory. Um. All right. So some of this stuff we're covering this stuff sort of relationship, some of this, you're not going to do a lot of this. Who knows if you'll ever do this. And the reason is that, you know, we're not doing so much porcelain fuzed to metal anymore. We're not doing full gold bridges anymore. Or at least, you know, less than we ever did. At the same time, in considering some of the material you need to be aware of in dentistry, some of this is stuff you kind of need to know. So we're covering it still, even though personally it's a little bit old. Okay. So I apologize for that. So we're going to talk about next is what we call solder relationships. This is a situation where you bring a bridge back. Or as we talked about I was showing you that little metal framework for that of the bridge. You bring it back, you try it in the mouth and it rocks. If you're doing something like porcelain fuzed to metal or some other metal, a material that you can solder, you have the ability to then cut it, create a relationship in the mouth, and then have it reconnected in the lab into one piece to solder it back into one piece. So the way we typically are going to do these things here at Bu, if you ever have to do it is we're going to do a salt and pepper technique. So these are some old slides showing it. You're just going to salt and pepper the way you do this in a spot like this where we have a gap between here is you're going to take a little liquid first on your brush. Place it. The liquid fills the space. Then you dip your brush in the liquid again, pick up a little powder, place it, and it'll kind of suck right through there in a kind of capillary action. And then you're just going to build up some extra around it to make plenty. So it's strong enough. And then you check that it's not rocking. If everything's solid you lift it out and you take it to the lab to be soldered. So you just remove it. It's going to go to besotted. Now if you want to get an extra index to be certain that it's not going to fail. And the reason you do this is you're probably all familiar with the idea that you have some lab thing you have, you're walking around with your models, and what do you do with models when you're carrying them in your hands? Exactly. You trip and drop them, or you just drop them, or one of your friends says, oh, that's an interesting case. And they pick it up and immediately drop it and break it, right. When we were in school, they used to tell us at all costs, never touch anyone else's models, because the first thing you do when you pick up somebody, bless you. The first thing you do when you pick up a model is you drop it and break their stuff. So. If you're afraid you'll drop the sort of relationship you can do an index. This is just a quick impression. Plaster index. It takes just a few minutes. And if you were to drop this and it fell apart, you could put these pieces back in place and solder off of that because it would be accurate. But that's the point of that. Here's a clinical example of an eight unit bridge. All right. So here we have this on the model. It comes back from the lab. We're going to try it in the patient's mouth. So we tried in the mouth and it rocks. So what do you do? You cut it. So here's a cut. We try this in. This fits nicely. We seat the other segment and it still rocks. So we cut it again, right? Right here. These cuts are made right through the middle of these Pontiacs, so that the solder joint that's created is going to be big and solid. You could also cut like this if you wanted. It would certainly be strong enough. But that was the choice I made. So we've cut it and now we're going to have to get a solder relationship. What you saw before is how we would do it here at school, where we do a solder relationship using either pattern resin or dually we use an acrylic. What I like to do, which you're not allowed to do here at Bu. But you can do on your own once you're away. Is I like to take a different material. What I have here is Krazy Glue. Right. And I'm using it with something called zap it liquid. Right. Zap! It is a product that's made for. I'm familiar with it. For dental technicians, it's it's essentially a two part Krazy Glue. There's a gel and there's an accelerator. So when a technician is using it, they can put the gel and get something the way they want, and then they can either spray it or dab some of the accelerator on it and it sets instantly. I'm just using the accelerator. So what I'm doing is I'm painting on some Krazy Glue, then I'm going to dab on some of the accelerator and it sets instantly. Yeah, yeah, but when I was a kid, didn't everyone? That's Dennis all have. SPEAKER 3 To do it. SPEAKER 0 There you go. Yeah, well, Dennis, Dennis, all make models, don't they, when they're little. You all have to play with stuff with your hands. Um, so I like this because it's really fast. It's like instant. You paint it on. Hit it with the zap it. It's set. That's it. The reason we don't let you do this sort of thing here at school is we don't want you to glue your patient's lip to the bridge with the Krazy Glue. If if as a dentist in practice with a license, you want to take that risk on your own, feel free. I do. I wouldn't tell you not to, but here at school, we won't let you. Okay, but that's what you're seeing. It's just, uh, Krazy Glue, you know, cyanoacrylate cement and, uh, zap it so it's lifted out of the mouth. I add a little extra stuff, it goes back to the lab to be soldered, comes back, we try it in, make sure it all doesn't rock, and we're ready to go on. Now, if you're going to solder in a traditional way and there's all kinds of ways to solder, but you can use a soldering investment. You take the bridge you want to solder, you mix up the investment, you stuff it inside anywhere. You don't want the solder to risk going, you essentially place it, you cede it, you let it set up right, so you seed it there, you clean away any of the excess and you put it into an oven. And if you're using something like drill or pattern resin, it goes into the oven and it burns out. It just, you know, burns away, vaporizes, and then it's going to be ready to be soldered. You can solder, in this case with a gas oxygen torch. You basically get the heat going. You put your little bit of solder and it heats and sucks right through there. And you create your solder joint. So. Honestly, you're probably never going to do this here at school. You may never do this the rest of your careers because the materials are evolving away from it, but we still believe you kind of need to be aware of it, right? Here's a couple examples of solder bridges. This is the solder. This stuff you see up here is the residue of an anti flux. So in this case because this was full metal we didn't want to risk solder getting on the occlusal. So we painted anti flux there. Wherever the anti flux is the solder won't go okay. The simplest anti flux that most of us are aware of is a lead pencil. But there's other products we could use where you might use a lead pencil if you were doing something like a gold crown. And this is one of the examples where gold crowns are great. And you go to try it in, in the contacts light, well, you take it to the lab or you might do this yourself because it's so easy. You draw a little circle where you want the contact to go. You put a little dab of the solder, you hold it over a Bunsen burner for a bit because the solder you're using is very low heat. It melts. It's contained within that pencil spot. You polish it a little bit, bring it back to the mouth, adjust your contact and you're all set. All right. So here's the relationship. Here we see this is the anti flux it's been painted on here. These are the solder joints polished you know very routine. You go back to the mouth. You try it in make sure it doesn't rock. And you're ready to go to the next step. Okay, now you can see I didn't want to spend a lot of time on that, but I want you to see it. We need you to see it. This is something you might do in school. Say you're doing, um, an all. Uh, zirconia bridge. But it's being built with porcelain facings, right? So Jerry described that kind of thing to you. You might do that. So what you could conceivably do is bring the patient in, try in the bridge. You verify that it seats right. You make sure it doesn't rock. You use your fit checker. You make sure that's good. Right. Get your radiograph. Everything's good. Uh, if it has occlusal zirconia, which we would typically use in the back of the mouth, you check the occlusion, polish it as needed. But say you wanted to give the lab a little more information of what the tissue contours look like. Because the model you have was with working dies. It's been cut. Right. Things have happened there. And there's no tissue anymore. So you might say, I'm going to do what's called a pick up impression. So you take that bridge, you see it in the mouth, and you simply make an impression of the arch and pull it. And that's what you're seeing here. Right. And then that's used to make what's called a master cast. And we'll look at that in a moment. So here's an example from our clinic at blue. Uh, this was student work. Um. Patient comes back. The bridge was tried in. The substructure. It rocked. It was cut. A solder relationship made. And it was soldered together. This is the point where I saw the case, so we took a couple pictures. And you can see the solder. It's a little different color. Now looking at that, there's something worth mentioning to you because this is actually important and a distinction about soldering. There's different kinds of solder. There's low heat solder and high heat solder, and you would choose according to the circumstances and what was needed. In this case, we're building a portion fuzed to metal bridge. So if we're going to be applying porcelain on here. Do we need a low heat solder or a high heat solder? High heat because we're going to be baking porcelain on here. That solder has to have a higher melting temperature than the porcelain oven, right? Otherwise it'll dissolve if we were in a circumstance. And I'll talk about that a moment where we might be doing what's called post soldering. We could use a low heat solder. Here it be you. If you're ever in a circumstance where you need to solder, you're going to do what's called pre soldering. That means that if you're doing something that can be sorted like a porcelain fuzed metal bridge, you would try the metal in. If it had to be cut and soldered, you would pre solder it. You would solder it before any ceramic was applied to it. That's pre soldering before any person goes on post. Soldering is done after the porcelain is completed, after it's even been glazed, it's completely done. The advantage of pre soldering is it gives you a chance to do these tri ends and verify that everything seats the way you want. The other advantage of pre soldering is once you solder you can drop it in water to quench it. And that creates a more ductile solder joint which is less likely to fracture later. Um. So those are the advantages of pre sorting. We like to do that here at school if you're ever doing these sort of circumstances. Post soldering is something that um in my case I've only ever done as a way to solve a problem at the last moment. So if I'm doing, say I was doing this bridge and everything seems right, I well actually go back to that. When we looked at before that, that eight unit case with the Anteriores say I do everything, I have the portion done, I do my trains, it's glazed. I bring the patient back to insert, and for some reason that day it's rocking. Not seating. Now there's different reasons that could occur. Where I've seen it clinically, most typically would be with a patient who has some periodontal issues. And somehow or another, we've had some movement in a tooth that we were unable to control, and now we have to deal with it in a circumstance like that, if I don't want to go back all the way to stripping off the porcelain, cutting it, pre soldering again and I want to just get it done, what I could do is cut it carefully where, you know, right between a couple teeth hopefully where it won't show and have it post soldered after the fact. And there's ways you can solve a problem. To me it's a very rare thing. It's something in my years and years in practice I've only done a couple of times, but there's been reasons. So this is pre soldered right. So you know it goes back to the mouth. We try it in. We make sure it doesn't rock. At this point we're going to be ready then to do what's called our pickup impression and make ourselves a master cast. The reason we're going to do that is let's go back a step and think about it. This bridge was made on our working model. When we came to the mouth, it rocked. Could we take it back to that model to do the rest of the case? No, because we know the model doesn't match the mouth. So we need a new model, right? We need a new model to work on. So we're going to pull this. In our pickup impressions. So you see this in the mouth. And then this raises a different question. We didn't go over this yet. Next week we're going to talk about occlusal registrations right. If you look at that and we're going to have a new model up here and we're going to want to mount that to the, you know, the lower model. As you guys look at it, you think we're going to want a registration? Yes, absolutely. Because we have no occlusion on this side. We need something. To put on this to orient the casts. This is a very good illustration of why you need a registration in certain spots, and we'll go over this stuff next week. So we're going to get a registration. In this case we're using acrylic. It's just a pattern resin. Um and we'll talk next week I think it is about a whole range of different materials you can use for registrations and how you use them. But this is one example of something you can use. You only use acrylics like this. When you are working with metal, you don't want to put an acrylic like this on a stone dye because it will abrade the dye and ruin it. But we have metal here, so that's fine. The nice thing about metal is it's very, very solid. So you know when it's seated just right. Yes. Clearance in terms of the bite and. SPEAKER 3 Yes. Well. SPEAKER 0 In a case like this. If it's so much that it's going to be a problem, then the truth is really moved. Our problem with these things is, you know, we're always working to tolerances of of microns, right. So if that tooth had and actually to go into it further, the reason I think I've seen it a time or two is teeth are a little compromised. And, you know, you go to cement to temp back in, right. You excuse me, you mix up your temporary cement. Now, in theory, if it flows properly, you're seated. It's all very even. What if your cement was a little thick on one of these teeth, or had begun to firm a little on one tooth? So now you push it in, the tooth depresses, you know, called a 10th of a millimeter into the socket, but now it's sitting there in the temp for a number of weeks. Bring them back, pull it out, go to seat your bridge. And all of a sudden it's not quite right there because that tooth is in a different position. It's probably something you did at that point. And it's so hard to get everything exactly perfect all the time. Then you might say, well, why are we even doing a bridge on a patient with any periodontal compromise? But there could be reasons patients age what they can afford their own desires. Um, you know, they might not be appropriate for implants. You know, there's all kinds of reasons things happen. So in terms of occlusion and clearances, it shouldn't matter, at least when I've ever seen it. Because if it's so far off like that, then you really have to go back and start over. So it's a good it's a good question. I've never seen it that extreme because and if you're working in something like that, you probably shouldn't be doing it. You know, you probably made a bad choice. Good. So here we have this. We're going to take our registration. We're going to set it aside so we have it for mounting the case later. Okay. We do our pickup impression. This is just improv game. We pull the whole thing. And now we're going to make what's called a master cast. Now there's a couple steps in making the master cast that are really important. The first one involves wax. You have to protect your margins, right? You've tried in the bridge, you made sure it fits just right. And you'll see in a moment. In making the master cast, we're going to add materials here. We're going to add materials out here. If you have that metal margin sticking up. And somehow in making the master cast in handling things, you in any way distort that margin. You've ruined everything which you really don't want to do. So what we're going to do first is we're going to just take a little wax and cover these margins with it, okay? We're protecting them. You don't need a lot and it's not going to affect the fit. Then we're going to take in this case Dall-E. You could use pattern resin the same way we're going to lubricate the inside of these. And what we're going to be doing is using an acrylic to make our analog of the prepared tooth right. And the reason we're going to put acrylic in here is if we just poured stone into it, it wouldn't hold up. The stone doesn't have enough strength. So when we separated it it would break. So we're going to use a salt and pepper technique. And we're going to fill these with acrylic. And then we're going to stick something in there to get a little extra retention. In this case they're just paper clips that we've cut and bent. It doesn't have to be anything elaborate. So we seat those in there. We do the other tooth. We let it set. So now we've got an acrylic analog and we're going to pour stone just yellow stone for our model. Okay, so we're just poor. The Yellowstone model. We're going to let that set and then separate it. When you separate this it may come out in one of two ways. Sometimes you'll pull it apart and you'll have these sort of acrylic analogs on your stone cast. And your bridge stayed in the impression. Sometimes the bridge stays on the cast. It doesn't matter if it stays on the cast. It's just, you know, maybe you didn't have enough lubrication, but assuming it is lubricated, you just grab this with something like a hemostat, give it a pull and it'll come apart. Okay. And then the laboratory can use this master cast to build their porcelain after you've remounted the case. In terms of remounting, it's just a couple of views. You're going to take your registration, right? Your bike registration you've made, you can adjust it a little bit, make sure everything seats the way you'd like and remount the case. All right. The laboratory then, as you could imagine here, now they have the contours of the tissue. This is all quite ideal. They can actually get a better contact when they build the porcelain. They can make a perfect contact for you and they can build the rest of the case. Right now, here's a kind of interesting thing I think. Interesting. This is a case involving a patient with some natural teeth and some implants. This. These units and these are on implants. Now, have you studied implants yet? You started a little bit. All right. And you may already know this from the past. With implants, you know that they're held in the bone. And unlike an actual tooth that has a PDL around them, implants don't move. There's not any wiggle room. Right. So when we go to try and say a a framework for a bridge, you know, three units here, natural teeth have a little wiggle. So sometimes you go to see them and it's pretty close. There's times you say, well here's a cotton roll bite on this. And you wait a few minutes and you go, hey, look it seated. You know, you get enough play that it works. Frankly, Dennis, depend on that all the time. It helps us that little play that teeth have. But implants don't have that. So anytime in this case we're combining these implants natural teeth. And we're going to be splinting the two implant restorations on either side. We want to try in this part and this part before we start dealing with that. Because we want to make sure that those two splinted implant units do seat properly, because the chances of needing to cut and solder this or that are going to be higher. So what we did is we had these made up. Tried them in, and in fact, they seated and fit perfectly the first time, which was lucky. That's nice. So then we made a final impression of the natural teeth, and at the same time pulled these in a kind of pickup in the back of the impression model was poured. So this is kind of a master cast bit here. This is a working model. This goes to the lab. All this is made up. Go to the mouth. And it rocked. It has to be cut and soldered, so it's cut. You can see this is an overweight Pontiac that was designed right. You see the shape of it. Our cyanoacrylate cement and Zappa saw the relationship made. And we'll go on. So we bring the patient back in. We try that in again after it's cut and soldered. It fits now and we can go on and finish the case. So the final thing we're going to look at here, this is just another master class. This is an older one. And with this master class, what I want you to see basically is we've made a soft tissue model. So if you get into a master class, one of the things that could be nice for the technician is the ability to make a soft tissue model. Have you seen that in the implant class yet? Yeah. No. All right. With implants we do soft tissue models essentially all the time. And the reason we do that is because the implant is buried deep under the tissue. And, you know, the implant has a little thin, round shape and a natural tooth typically has a big oval shape or some different shape than the shape of an implant. Right. So between the head of the implant and where you see the natural tooth in the mouth, if you're doing a single unit or even multiple units, you want it to transition into something that looks like a natural tooth growing out of the gums. By making a soft tissue model, it allows the laboratory to build that contour. They can reconquer the soft tissue, model more easily and manage it. So this is a soft tissue model, which in the master class is going to allow the technician a better ability to sort of look at and manage everything here without getting into all the details. Here we have our various occlusal, you know, registrations. The case can get remanded and ultimately the person applied and it can go into the patient's mouth and the patient's happy, so it's all fine. This is, you know, essentially using all the different things we've looked at. Any questions at all before we stop for today. Okay, so in that case, we're all done with this for the moment. Um, uh, it's about quarter of. 20 minutes, ten minutes. Five minutes. Not five. Not ten. SPEAKER 3 15 seconds. All right. SPEAKER 0 1005. 1005. 1010. Try not to be late because we have a big, not a big, but we have a demo to do which I'd like to get out of the way for you so you can get to work. SPEAKER 3 Just the. SPEAKER 4 Case of temporary bridge.

JAN 26TH 2024.docx

Document Details

Related

Full Transcript