Have you ever prepared the last molar for a crown? And just when you check the occlusal reduction, the patient bites down and as if by magic, the reduction has all DISAPPEARED?! It is the phenomenon that we call ‘The Last Tooth in the Arch Syndrome’
This episode with Dr. Mahmoud Ibrahim will give you more confidence in recognizing, screening, and managing such complications in practice. But like I say in the main episode, optimistically, this phenomenon will never happen to you AGAIN if you follow these protocols for screening.
Protrusive Dental Pearl: Watch out for the patient with quite flat teeth as they are more susceptible to the last tooth in the arch syndrome / bite change. They do not have good posterior coupling/stability and therefore more likely to ‘forget’ their bite as the cuspal inclines do not guide the mandible back in to maximum intercuspation.
Highlights of this episode:
- 2:41 Protrusive Dental Pearl
- 6:09 Introduction to Dr. Mahmoud Ibrahim
- 9:34 What is Centric relation?
- 10:45 Last tooth in the arch syndrome
- 13:14 Risk assessment for Last Tooth in the Arch Syndrome
- 15:52 Screening patient’s CRCP and the degree of slide
- 17:33 Leaf Gauge protocol for screening CRCP
- 30:23 Communication with High-risk patients
- 34:35 Case Discussion
- 44:36 Management of space loss after preparation
- 46:24 Dr. Mahmoud’s top tips to prevent the ‘Last Tooth in the Arch Syndrome
- 58:47 Occlusion Basics and Beyond
Dr. Mahmoud Ibrahim and I are currently working on a huge project called OBAB, Occlusion Basics and Beyond – it will be the best occlusion resource in the Milky Way…and that’s our mission! We want to finally demystify Occlusion and make it Tangible AF!
Join the waiting list HERE!
If you loved this episode, you will like If You are Not In Centric Relation, You Will Die
Click below for full episode transcript:Opening Snippet: Because it sounds horrible, but if it's happened with all the sequelae of you losing space and bite changing, that is a big deal. I mean, this patient that might be looking at ortho might be looking at a rehab, who's paying for that? Chances are you. So for two minutes screen that you can do. And once you get good at it, it's, it's really, really quick. Just to buy yourself that peace of mind and being able to inform the patient and gain proper consent when you're restoring the terminal tooth or maybe the one in front. That two minutes is worth it in my opinion.
Have you ever prepared the second molar or the last molar of the patient’s mouth for a crown? And when you’ve checked the occlusal reduction, you get the patient to bite together. And it’s as if you NEVER DID ANY OCCLUSAL REDUCTION. You think what the hell is going on? I swear I just sunk a two millimeter bur into this tooth. And now it’s like there’s hardly any space there.
What’s going on? Has that ever happened to you? Has that problem bitten you? Have you had that dreaded phone call from the lab saying, ‘We need a bit more space here, Doc.’ If you experienced this, you probably searched it and spoke to prosthodontics and got some information about LAST TOOTH IN THE ARCH SYNDROME where that space magically disappears. What’s behind that? Why is that happened? Why, if you’re not careful, it could happen to you could happen to anyone I know some great dentists. And it’s happened to them. So no one is immune to this. However, the topics that me and Mahmoud Ibraham, my guest today will make sure that you will a be able to screen when this issue might happen. Have a conversation with your patient ahead of time and sometimes consider a change of treatment plan because you know that as soon as you prep the second molar, you’re likely to lose space and to have that knowledge and screening for assessment is just absolutely fundamental.
And of course, we will also talk about what actually, what do you do when that does happen? How do you manage that situation when you’ve lost that space? So yet again, it’s an occlusion based episode with my good buddy Mahmoud Ibrahim, we’re actually working really hard at the moment where we’re creating a huge project called OBAB. It stands for Occlusion Basics and Beyond. And the vision is like really, really bold. Like they say that when you, your dream, if your dreams don’t scare you, then what’s the point? So the dream that’s scaring me and Mahmoud and we’re working really hard behind the scenes like think 4am wake ups and late nights to you know, surrounding our clinical dentistry that we do in family lives is building OBAB. The occlusion course that will start from the very foundation, single tooth stuff think when I place a crown, what should my dots look like? How can I plan to go beyond a single crown? At what point later like modules four and five, raising the OBD. So we’ve got so much plan in terms of the most comprehensive, thorough, tangible and best occlusion course there is in the world in the universe ever. That’s the dream.
So it’s a extremely bold claim. So give us a few months as we’re kind of halfway through at the moment. We’ve got the beta testers, you’ve got people like Tif Qureshi giving us advice and coaching us as well to make sure that this course is going to be absolutely sensational. So get a bit of a flavor of that today. But we will go in depth into this. So you will feel much more confident about last tooth in the arch syndrome, recognizing, screening and managing such complications in practice. But hopefully, like I said after this episode, it’s never going to happen to you.
So that was a longer introduction. Hello, Protruserati. I’m Jaz Gulati if you’re new to the podcast, welcome. It’s great to have you, to the usual listeners get some onions get ready, it’s gonna be a good one here.
The Protrusive Dental Pearl:
The Protrusive Dental Pearl I have for you is very much related to this. Any type of dentistry that you do, including full coverage, occlusal appliances, or partial coverage, or anything that you do has a risk of changing the patient’s bite. In fact, sometimes you might have even met a patient who said, ‘You know what my front teeth used to touch together, but now they don’t touch anymore. And when my bite has changed, they didn’t have any restorative dentistry or splint or anything.’ But they had experienced this bite change. So what’s behind that? Why does that happen? Well, there’s loads of things that can be changed at the condylar level, for example.
But how do you know who’s at risk? So I always want to look at posterior stability. Now what I mean by that is imagine someone with really well defined cusps, what kind of population have a well defined cusp, young people, right? They don’t have that much wear and young people have got these lovely pre molars and very acute inclines and very cuspy teeth. So think of that term ‘cuspy’. Cuspy teeth on their molars and premolars. Therefore, when they bite together, if their bite was to keep changing, for some reason, actually as the mandible closes into the maxilla, it’s those cusps as well defined cusps that guide the lower jaw and the lower cusps in to the maximum intercuspal position which is their normal bite. So if someone has got that really nice bite ie like a classic class one Andrew’s keys with not that much wear, I’m gonna say that is a very occlusally stable patient. So you’re saying, ‘Okay Jaz where’s the tip though?’ The tip is, watch out for the opposite of that patient. Watch out for the patient that’s got quite flat teeth. And actually, they might not have a well defined bite. When they bite together, you see lots of spaces and abrasions between their back teeth. And there’s only like point contact, and there’s nothing really guiding the lower jaw into the morphology of the upper teeth. This is a population of patients who are more susceptible to the last tooth in the arch syndrome, which we’re discussing today. These are the group of patients that even if we give a full coverage tenor appliance, their bite might change for good, ie take the splint off and their bite has been changed. Because they already have this feature that the teeth don’t mesh together very well. They don’t mate together very well.
And therefore they’ve kind of got these multiple bites and because of this lack of occlusal stability, you’re at risk. So the pearl is have a look at your patient have they got good occlusal stability? Or poor occlusal stability? And if you’re carrying out let’s say an occlusal appliance, it’s even though it’s a full coverage occlusal appliance, your bite could still change. So I would go back to splintember series. So go to the podcast old episodes, splintember, around about episode 39, 40 onwards, we covered a whole series about occlusal appliances and watching out for bite changing stuff. You can go to that as well if you want to learn more about these things, but just assess your patient’s occlusal stability, make an entry in the notes. But of course it’s something that you gather from photographs as well.
Now let’s join Dr. Mahmoud Ibrahim and talk about last tooth in the arch syndrome. Mahmoud, my brother from another mother, welcome back to the Protrusive Dental Podcast yet again for occlusion. How are you?
I’m good, man. Thank you very much for having me again. So- [Jaz]
We left off last time saying that we need to cover last tooth in the arch. And literally someone the other week messaged me saying, ‘Jaz, you mentioned Mahmoud is going to cover last tooth in the arch. It hasn’t happened yet.’ It was quite a bit of mess around with Mahmoud. Come on, the people out there want it. So let’s make it happen. And so just remind those who maybe for some reason have not listened to basics of occlusion part one and two, it was part two that we did it together, we covered some really cool concepts at that point. You know, just building on the foundations of that part one. Who are you? Where do you work and why do you love occlusion so much, man? [Mahmoud]
Well, okay, my name is Mahmoud Ibrahim, and I’m a general dentist, I work in Telford and in Birmingham suit. And I’ve been qualified since 2005. My journey in occlusion kind of started really about five years in once I’ve decided I actually want to stay a dentist. My gonna repeat all that, for occlusion for me really is born out of the fact that I don’t want my stuff to fail. I don’t want the patients coming in with broken restorations. And it fascinated me because of its relation to physics and forces and things like that, which is something I’ve always loved at school. So yeah, it’s it’s always attracted me and it’s a very poorly understood subject because it is a bit abstract. You know, it’s not as easy as step by step 123 bonding or whatever it is. So yeah, it’s- [Jaz]
It can get very philosophical and that it’s a double edged sword. It’s annoying thing but it’s also cool just there’s been people from different occlusal religions and camps in here, how do they approach it and how these other guys approach it? I think, me and you what we’re putting together as you have heard of the announcement of the episodes go that Mahmoud and I were putting something together quite comprehensive when it comes to occlusion starting from the very basics, occlusion basics and beyond. And there’s something we’re very excited to put together and so it’s, I’ve been spending a lot more time with you. It’s been great. And discussing these philosophies and having some was shawarma wraps and discussing, you know, canine guidance and stuff, and all that kind of stuff. So we’ve been we’ve been doing all that it’s been great. But today, let’s very much cover last tooth in the arch syndrome. So Mahmoud, just to set the scene, right? Most dentists, they probably learn about this, when it actually happens. So when they prep a second molar, it doesn’t have to be second molar, obviously. But let’s go for the classical scenario, they prep a second molar and they swore that they prepped, you know, two millimeters or whatever, right? And they get the patient to bite together for the bite reg, and wait, all that space, almost that space is now lost. And they’re like, ‘Wait, did I just dream that I prepped for like last, you know, 20,30 minutes to this tooth? Did that actually happened? And then they like, oh, there’s a such thing as a last tooth in the arch syndrome. And then they have to, like, have that very awkward and difficult conversation with the patient when they haven’t understood themselves. What’s happening? So just describe what is this phenomenon? And how did you, I want to know how did you learn about it? And it happened to you first, and then you learned about it? Well, you’re always smart about it from the start. [Mahmoud]
I’m not gonna say I was smart about it. But what does what happened to me is for a period of five or six years, I was truly obsessed with occlusion and I read absolutely everything I could. So luckily, for me, I discovered a lot of these pitfalls before actually happened to me. However, saying that I did get caught out anyway, and it will happen. I got caught out by a upper second molar. I was prepping the two teeth, six and seven. I did my screening. And according to my screen, it was on the other side. But and we’ll get to this. Some people actually have centric relation contact points or points of initial contact or prematurity is in the CR on both sides. It can happen. So luckily for me, I lost a little bit of space on the provisional. And I was able to prep a little bit more, but we’ll get to that. To sort of describe what last tooth in the arch syndrome is, I’ll just take you back a step, the loyal Protruserati, it would have listened to basics of occlusion part two. But if you haven’t, or maybe you’ve forgotten, it’s important to describe what centric relation is, because that’s how it started at the last podcast, you said, what are the uses of centric relation, and this topic came up. So this is a quick reminder centric relation, I think Jaz you and I both like the description of the condyle as snug as possible up in the fossa. And really the technical definition is, it’s a jaw relationship, it’s irrespective of the teeth. And it’s where the condyle sits up against the anterior eminence of the anterior wall, in the glenoid fossa. But practically, for me, it’s if the back teeth are out of the way, and the lateral pterygoid muscle is fully relaxed, the elevator muscles contract and they seek the condyle up into the fossa as far as they’ll go. The reason that’s important is because in 90% of the patients, or 90% of people, when that condyle is fully seated, and the patient closes, they’re only going to touch on one or two teeth. Now to get all your teeth together, which is something you need to do to swallow or as many of your teeth as possible together. Usually the lateral pterygoid contracts and it pulls the condyle down the eminence a little bit to be able to get all your teeth together. So essentially that initial contact on those one or two teeth programs the lateral pterygoid to contract and bring the condyle down so that you’re the rest of your teeth meet. Now this becomes a learned response in your lateral pterygoid to automatically. So last tooth in the arch syndrome comes in when you inadvertently not knowingly remove that initial point of contact. And in a way you lose some of that programming of lateral pterygoid. So lateral pterygoid either doesn’t feel the need to or forgets how to pull the condyle down. And essentially, the condyle seats, maybe not fully, maybe just a little bit, but it’ll seat up and back a little bit. But what happens is your condyle’s attached to the rest of your mandible. So as the condyle goes up, the rest of them will goes up a little bit, up and back. And let’s say you’re prepping a lower second molar, that’s gone up a little bit. So what’s happened to your occlusal clearance that you created, you’ve lost some of it, all of it, if you’re lucky. And that’s what this tooth in the arch syndrome is. And like you said, it doesn’t have to be the last tooth, you know, it could be a six, it could be a seven could be a five. But the important thing is there is a wait screen for it. And we’ll get to that. But that’s what it is in a nutshell. [Jaz]
Yeah. And I just want to put for those who listened so far. And they’re still you know, these terms can get really confusing. I like the fact that you started off with the definition of centric relation. But just some other terms that people may be familiar with from dental school, maybe RCP, retruded contact position. So we don’t tend to use that term anymore, even though dental schools might do, because it implies that the condyle needs to be shoved all the way back into the cliche era of dentistry, it’s not the case, we know that it’s more anterior superior. And it’s interesting how the definitions have changed over time. So again, go back to that episode, basics occlusion Part Two, to get a more of a sense of that. So RCP, you mentioned the point of initial contact, the centric relation contact point. So whenever the muscles are relaxed, and sort of the condyle, supposedly is a bit of rotation, you know, we can debate all that if you would like to. But it’s that retruded contact position, which you may have heard of before, or me and Mahmoud, like central place and contact position. And at that position where you got to start screening and when to come on to that in terms of your prevention. So we’re going to talk about how to screen for this. But maybe, well I think we should I was gonna say yeah, let’s go with that first, because someone might actually come on to this podcast when this actually has happened to them. And the bit they really want the most is, ‘Wait, crap, what I do now? Mahmoud, Jaz get to the bit where what would I tell my patient?’ Because I don’t want to prep anymore. If I prep anymore, I’m gonna see red. And so how am I going to do this, this crown restoration, if the bites changed and whatnot. So I guess the plate because of that person, maybe just wait a bit, we’ll get to that about what if you act, you know, step up, or you didn’t know about this, and you’ve joined this podcast, welcome to the podcast, by the way. I’m sorry that you’re joining us in distress scenario. But we will all cover that, don’t worry. So, Mahmoud, who is acceptable? Who is at risk? Because just like you said, 90% plus of people have a first point of contact, ie, their normal bite, the MIP, the maximum intercuspal position is when most of their teeth or lots of the teeth touch together, it’s the bite of best fit, which is going to be different to when you put their condyle into centric relation. And that’s a different bite. So 90% of people fit into this category. But who is actually at risk of this happening to? So let’s start off by the fact that you have to be preparing a tooth for this to happen, you know, to you in the context we’re talking about right? [Mahmoud]
Yeah, I mean, you have to be altering the tooth somehow. I mean, it could be that you’re, you’re filling it, it could be that you’re extracting it, you know, if the tooth is unrestorable and it’s infected and it’s got to come out. I mean, you’re gonna take it out. But yes, as long as you’re altering the surface that’s contacting in centric relation this could happen. The highest risk is when the difference between the center correlation and the maximum intercostal position is large. Okay. So, essentially, luckily for us, again, most of the people that have a centric correlation to MIP shift, that shift is a millimeter at most, okay, for most people. If you think about it, if the condyle can only really move up a millimeter, even if that’s completely vertically, which you won’t be it’s at an angle, the chances of you losing enough space for it to be a problem are very low. So in my opinion, you want to be screening, whenever you’re prepping a molar, if you want to be really extra, you can check it when it’s a pre molar as well. But last tooth in an arch, definitely check, you know, if it’s second to thin might be worth a check as well. And once you know whether or not they have a big shift, then you can figure out what to do. But I would always screen a last tooth and maybe the one in front and get on to how we do that. [Jaz]
Well, I think before we choose to restore that tooth, you know, could be the second last tooth or the last tooth in the arch. And we’re thinking, ‘Okay, I remember listen to that podcast. So I better I better do this check now to make sure it is a patient at risk or not.’ But just like you said, this might be happening to us in the population all the time. But the differences and changes so small, that, you know, we don’t notice it as much. So thankfully, our patients are kind to us. And actually, you know what? This has never happened to me, I actually got way smarter to this before it actually happened to me and I started screening before ever happened to me. So it’s never actually happened to me. And then I’ve used different techniques like the island prep and stuff, which we’ll come to later to prevent it happening. So it’s never happened to me, but I guess it might have happened to me unknowingly. But it’s happened to such a small degree that we don’t actually notice, because the seating is not significant. So let’s say we’re preparing a tooth, how would you check if that tooth is the central patient contact point, and therefore, how can you check to what degree the slide is? [Mahmoud]
Okay, so my preference is to use something called a leaf gauge, what I’ll do is I’ll just search for my screen. [Jaz]
So we’re going to make it very tangible for those listening at the moment, obviously going to describe everything we’re seeing, because the loyal Protruserati was started out. Started out on Apple and Spotify and whatnot, Stitcher, etc, we’re going to make sure we never forget you. But for those who are watching on YouTube right now, then yeah, you get to see some visuals as well as a commentary. [Mahmoud]
So essentially, a leaf gauge is a bunch of sort of plastic leaves, and you can add or take away leaves to make it thicker or thinner, or you put it in between the incisors at the front. And essentially, it creates an anterior jig that separates the back teeth. So you put in enough leaves to completely lose contact at the back. If that, if you put it between the teeth and the patient close on their back teeth and they squeeze, they cannot feel any of the back teeth touch. Now this is essential that you completely clear the posterior contacts. Because if you don’t, then that’s when you don’t really know whether or not you’ve stretched lateral pterygoid as much as possible. So if you only put in a few leaves, and the patient says yep, I only contacted the back here, you check with the paper, and yet, there’s only one tooth that contact. Now, that might be the fully seated position. But it might not be you might find that you can actually add a few more leaves. And they’re still contacting but it’s in a different position on that tooth. So you clearly the context completely, fully stretched lateral pterygoid. And then you start taking leaves down to- [Jaz]
I was gonna ask you a question, I would which I actually get a lot right for those beginning start with a leaf gauge. And they’re like, ‘How do I know how many leads to start at the beginning? Is it that second round is what should I start with 15? Should I start with 20?’ So what’s your protocol? How many leaves we’ll just start with? [Mahmoud]
I mean, to be honest, I’ll start with 10,11, something like that. If the patient looks like they’ve got a normal overjet, overbite relationship, if they’ve got an anterior open bite, I’ll use half the pack. Yeah, we’ve got a really deep bite, or use maybe five. And then you just take it from there. Once you’ve done it a few times, you’re, you start to sort of see it in your mind, you can eyeball it. But yeah, maybe- [Jaz]
And you can get very predictable and consistent results with this, I think. And then the key lesson here, guys, is to make sure that you put enough leaves in, even with just one or two extra that the back teeth cannot touch just like Mahmoud said. So make sure no back teeth can touch. [Mahmoud]
Exactly. So once you’ve ensured that none of the back teeth are touching, you’re going to have the patient go forward and back. I let them do this for maybe 30 seconds because it just helps deprogram the lateral pterygoid and I’ll get them go forward. So I learned this from you Jaz, it’s great tip. Ask him to go forward like a bulldog, and then go back as far as it’s comfortable. And I get them to squeeze. Ideally want them to squeeze off half hard as JR one calls it half hard on both sides. ‘Can you feel any of your back teeth touch?’ They say no. Then you ask, ‘Can you feel any tension or tenderness?’ The reason why I ask is because I want to make sure that the lateral pterygoid has relaxed if it hasn’t and it’s a bit tense. They’re gonna say maybe I can feel a little bit of tension. But the other thing you’re checking for is essentially you’re load testing the joint. So you’re compressing that joint a little bit and seeing if there’s any pain, if there is any pain then that joint is unhealthy? Do you really want to start messing around with someone’s occlusion potentially with an unhealthy joint? So, once you’ve done that- [Jaz]
Just before you continue Mahmoud, our talk is load testing, I mean, we can speak for an hour just on load testing. But I think it was worth just having this visual and you know, if you’re driving, if you’re chopping onions, wherever you have this visual, if you’re new to this concept, that if you’ve got these plastic leaves in between your front teeth, right, and you bite on these plastic leaves, okay, what’s happening? The central incisors are going to be intruding within their PDL. Okay, but then what about all the rest of the force, where’s that going to, right? Well, if the leaves are contacting your incisors, okay, and your muscles are going for it, the only other thing that can can now move is the condyles. So if the condyles are now going higher, and pressing in to the glenoid fossa, you have now placed load in the TMJs. And this is what load testing basically is, we’re now loading the glenoid fossa, we’re loading the temporomandibular joint. And then just like Mahmud said, if someone’s saying, ‘Whoa, what did you just do Mahmoud that really kills?’ Then maybe this is a complex patient. And you know what, thankfully, these patients are rare. I’ve never had an okay. Like once, maybe. And this is that was a TMD evaluation. So I was expecting it right? Like a severe intracapsular issue that was acute that gave us responses. Thankfully, this is rare. So I actually know some colleagues in our experience colleagues who said, you know, I stopped load testing now, because I realized that it wasn’t adding much, I still think it’s a good thing to do. And good part, the thing to do part of your notes, because you never know when you can get surprised. But definitely that, what I like about what you said, Mahmoud. And for those who might have missed it when you said it is your testing to see if they’re feeling any tension. And that’s the lateral pterygoid stretching, you want a position where when they’re pumping half hard just like Mahmoud said, they don’t feel any tension. And that tells you, okay, lateral pterygoid to stretch, it’s relaxed. It should be a nice and relaxed and comfortable position. It shouldn’t be like aching there. And what do you do Mahmoud? If they say, ‘Ya know what, I just feel strange tightness up here.’ And they’re pointing to a master and lateral pterygoid. What’s your protocol? [Mahmoud]
So, the what I’ll do next, if they say that is I’ll get a couple of cotton rolls. So I’ll take a leaf gauge, I’ve got a couple of cotton rolls, put it over the molar area, and I’ll get the patient to squeeze on it for a couple of seconds and let go. Squeeze on it for a couple of seconds and let go do this five to six times [Jaz]
Between the molars? [Mahmoud]
Between the molars on both sides. The idea there being is you’re getting the elevated muscles to really contract and what they’re doing is they’re trying to seek the condyles up and forward. Because if you consider the vectors of the muscles, that’s the direction they’re gonna pull the condyle in, and they’re just trying to gently stretch that lateral pterygoid. You know, if you get a cramp in your leg and you’re trying to stretch it out, you pull, pull your foot up, same sort of thing. Once you’ve done it a few times, put leaf gauge back in, get them to go forward, back as far as is comfortable squeezed half hard on both sides. Can you feel a tension attendance? Most of the time it’s gone. [Jaz]
Yes. Agreed my experience as well. And I just want to say Mahmoud, I’m sorry for interrupting. But really important to mention that when Mahmoud is taking out that leaf gauge, and putting in the cotton roll, and taking out the cotton roll and putting the leaf gauge at no point is a patient able or should be able to bite together make sure the patient does not bite together. Because then the neuro musculature just remembers again and they go into MIP or whatever. And then you have to deprogram all over again. So really important point we haven’t mentioned yet is that make sure their teeth don’t touch together. [Mahmoud]
Yeah, so the two keys, really in terms of deprogramming is don’t let theback teeth touch. And make sure that when you are dialing the leaves in, you fully clear the contacts of the back. Don’t get complacent, think out there only touching one. Just get some more leaves in there. Make sure it’s open, get them to deprogram a little bit and then do your load test. Then if you’re happy, then we do the screen. [Jaz]
Carry on. I’m liking others going. So yeah, what next? [Mahmoud]
‘Cause we are load tested with deprogrammed relatively. And now we feel comfortable that the condyle is seated. Now we’re going to start taking leaves out. So again, patient opens, you stick your finger in there, so close, take one leaf out, put leaf gauge back in, go forwards like a bulldog, back as far as it’s comfortable. Squeeze half hard on both sides. Can you feel any back teeth touch? Now you’ll get to a point where they will say yes. And what I’ll do at that point is I’ll put my articulating paper in with the leaf gauge, again, open up please put the articulating paper in on the side. They said they could feel it. Leaf gauge back in, forward and back and squeeze. Can I feel it sort of grabbing? If I can, I’ll actually now check it on the other side as well. Why? Because I got caught out that time. So it took on the other side. Often, if they can feel it on both sides, I will actually add a leaf back in because it could be that they were touching before but they just needed a little bit more pressure on the PDL at the back there to actually register. So add one more leaf and do it again. And ideally I want to be able to get one tooth to grab shim stock with the leaf gauge in, so leaf gauge in. You know I’ve identified where the contact is with my articulating paper, put the shim stock over there, forward back and squeeze tug. If it’s catching that shim stock where everywhere else isn’t. I know that I’m pretty comfortable that that is their actual centric relation contact point. And the question then becomes is that the tooth that you’re going to prep? [Jaz]
If it is? [Mahmoud]
Then you need to be careful, then you need to take into account everything we’re going to say next. If it isn’t, fine, you know, document your notes. And you’ll know for next time, you know, you have to do the screening again. So once you found out that it is, then you need to start collecting maybe a little bit more information. [Jaz]
So the next thing is probably to see, okay, now you’ve figured out that the upper left second molar is the first point of contact, and hey, guess what you were going to do a cuspal covers restoration for that tooth, and you’ll be altering that contact. And now what your going to be doing is figuring out okay, what am I up against here? Am I up against a patient here? Who the loss of space is gonna be so minimal that I don’t even need to sway anything? Or are we really at risk here of losing everything? And then I better tell the patient upfront, and maybe even this disagreement isn’t even viable. But we’ll come to that those extreme ends, right. One is, it doesn’t matter, I’ll be fine. And the other one is, whoa, you need ortho. You need surgery? We can’t even do this. So we’ll talk about that – yes. [Mahmoud]
Yeah. All right. So most of the time, you’re going to find that if the tooth that is centric relation contact point or point of initial contact is the tooth that you’re prepping. Usually, you’ll find that either A) it is the point of initial contact, along with maybe another tooth that puts you in a low risk category, because you know, the other tooth is going to provide the programming for the lateral pterygoid or- [Jaz]
For example, a tooth in front or a tooth on the other side? Is that we mean? [Mahmoud]
Usually it’s on the other side. Yeah, usually, because if you think about it, when there are leakages in at the front, and both condyles are seated, the condyles are sort of the other two legs of the tripod if you like. And you can imagine that if it’s close enough, there’s actually a little bit of bend in the mandible. So it’s actually possible to get two contacts. In fact, if you think about it, logically, it’s, it may be even more more likely to have to, unless one is really quite far ahead of the other, does that make sense? There’s probably two, or at least close enough to being two. So if it’s one of two contacts in centric relation, then it’s a very low risk. The other thing I like to look at is, you know, if you look at the picture, you can see if the tooth is holding up, you know, the bite, so you’re in centric relation, and that tooth is the only contact in centric relation, but the teeth next door look like they’re almost touching. And they’ve got good sort of Cusp fossa interdigitation. Again, chances are, you’re not going to lose that much space, because those bottom teeth only need to move a tiny bit for them to hit the upper teeth. So really, how much space can you lose? Not a ton. But also, they’re probably close enough together, that that programming for the lateral pterygoid is still going to happen. [Jaz]
Okay. And the last thing I look at is the sort of how big the slide is, there’s a few ways of measuring it if you like. Maybe the easiest way is just see how many leaves you’ve had to put in. That gives you an idea, we know that on the leaf gauge are mostly gauges, each leaf is about 0.1, a 10th of a millimeter. So 10 of them is a millimeter. Now, if you remember from middle school, sort of opening the vertical anteriorly three millimeters gives you about one millimeter opening at the back, that three to one ratio you can use. So if you’ve opened them three millimeters at the front, and chances are they’ve only opened a millimeter at the back, which means to close them back to MIP, you need to lose a millimeter off of whatever is holding them up, which are the front of the leaf gauge but the back is your central relation contact point. The other way to do it is you can actually put leakage in, get them into centric relation, get them at the point of initial contact and measure the overjet, then you take a leaf gauge out, get them to bite into MIP, measured the object again. Subtract one from the other, you’ve got the difference between the two. And that’s actually the horizontal component of the shift. So for me, anything that sort of less than two millimeters, or you know, anything less than one and a half, I’m probably not too worried, because it usually means that the shift at the back is actually quite small. [Jaz]
Okay, so- [Jaz]
But Mahmoud, that means something about that perhaps should have answered earlier. But all these things we’re assessing, like, if the rest of their teeth have got such a good mechanical interlocking, that they fits so well into a jigsaw, even though they have that first point of contact, which you may be altering. Do you subscribe to the theory that actually when they just go searching for their bite of best fit, they will just find it because the rest of it, they just interlock so well. And that perhaps it is because what I believe in please tell me if you don’t is that you’re more susceptible. If you’ve got general tattered occlusion, wear, lots of MOD, flat amalgams and you really don’t have much of a bite to grasp onto. Would you agree that perhaps that patient will be more susceptible? [Mahmoud]
Absolutely. I mean, it’s the same things when we discuss to people with a risk of an anterior open bite when you give them an anterior only appliance it’s the same thing. So if they’ve gotten good cusp to fossa contacts at the back, chances are they’re not going to lose MIP when you get rid of one centric correlation compound contact point where they’ll find something that is close enough. So yeah, the risk is pretty low. So really, it’s people with big shifts, or people where when they’re hitting that one contact in centric relation, you know, so what I like to do is I’ve got leaf gauge in there sitting on their centric relation contact point, I’ll, you know things back a little bit, I’ll put my mirror in there, I’ll have a look. If the teeth are really far apart, you know, in front of my tooth that I’m gonna prep this is like a two millimeter gap. And then I’m thinking, okay, I might be in trouble here. And because for those teeth to come back together, again, I know the mandible has to move up about two millimeters. Now chances are, it’s not going to move a full two millimeters up. But if it moves one and a half, and I’ve prepped one and a half, I’ve lost all my clearance. And now I’ve got another one and a half, which means I’ve prepped a total of three, you know, with my eyes, probably four millimeters off the occlusal surface of the stoop. So I hope it’s- [Jaz]
And the second molars tend to have small clinical crowns, because you’ve got that, you know, not Gingival overgrowth, but they’re, they quite often they are small, clinical crowns anywhere from either wear or they have altered passive eruption of some sort for the gums. So you’re already dealing with smaller clinical grounds. [Mahmoud]
Yeah. So you don’t really want to be adding millimeters to your prep, or at least you need to know about it in advance. So you- [Jaz]
So you’ve found this high risk patient, I’m always fascinated by how do you actually seat them up and say, ‘Hey, you have this issue.’ I mean, it’s such a complex thing to explain to dentists, how do you explain to a patient? [Mahmoud]
Yeah, so I mean, I think this is so key. And it’s the fact that it’s their problem. So all you need to do really is just sit them up and explain what you see, tell them nobody has ever put a leaf gauge in their mouth. No one’s ever checked this in any way. And they will probably already be feeling by others get really cares, or this guy knows what he’s doing. So I seat them up. And I’ll say, ‘Sorry, Mrs. Jones, my screening has shown that your bite is in such a way that if we do the treatment we’re discussing, and I try and put a crown on that your bite might irreversibly change, to possibly a degree where you can’t find your bite anymore. And in that new bite, there’s no space for the crown.’ Okay, so the crown- [Jaz]
And that’s a, you’ve explained that beautifully, but you know, for patients to actually grasp that, it’s tough. [Mahmoud]
It is. And, you know, if you’ve got some diagrams, or if you’ve got, you know, a skull, or, you know, I use the diagrams I’m showing on the screen now. Because it shows a series of me prepping the tooth off of the models and showing them that might come back together again, and it is a complex thing to explain. But usually I’ll try your best to explain it in my opinion. And, yeah, I found patients do understand, bite changing. So you know, the fact that it’s just one tooth, and it’s gonna change everything, obviously sounds a bit. Really, that sounds like, that sounds ridiculous. But you just have to have conviction in your, what you’re saying, because it’s true. [Jaz]
Yeah, I just like to add the way, the way I would say, the way I do say to patients, is we’re preparing preparing this tooth, which is right next to your joint, it’s like the furthers back tooth, right. And so if you change anything, this tooth actually is so close to a joint, you actually change the joint a bit. And then if you change the hinges of the door, the entire position of the door actually might change, you know, change the hinge of the door, you completed all the angles go off. So basically what this means for you, Mrs. Smith, is that this is just a little bit more complex. And you could have a bite change. And I love the fact that you also agree that bite change, is that is main thing, because that’s what they perceive. And then so therefore, we need to take more care and how we treat you. And then instead of boring them with a whole plethora of further information, just tell them, here’s what I’m gonna do differently to prevent this from happening. But just know that it could happen, that’s essential. You don’t want to over complicate it and you make it a half an hour discussion. [Mahmoud]
No, you don’t want to bore the patient to death. But they need to understand that this is something to do with their bite. It’s not something you have done or will do. You know, as the saying goes, if you tell them before it’s a reason you tell them afterwards, it’s an excuse. [Jaz]
So this is a patient probably I’ll describe it to our listeners, she’s got a massive CR to MIP shift. So her first point of contact is on an upper left seven, you can see the palatal cusp sort of dangling, you’ll see this on a lot of patients. The upper palatal cusp on seven sort of the tooth rotates a little bit buckling, and that palatal cusp hanging down, and it’s hitting against the distal marginal ridge of the opposing six. [Jaz]
Hey guys, hope you enjoyed the episode so far. Remember that you can claim CPD for this episode, and all the other 99% or so episodes are eligible to claiming your CPE or CPD certificate. As well as that on the app. You can download it on iOS and Android. There’s a whole load of exclusive content has a lot more plan. Like my biggest thing that I want to do early in 2023 is to Verti Preps for plonkers, right? So it’d be like a complete definitive guide to Verti Preps, I’m not going to post on YouTube. This is like gonna take a lot of extra hard work. It’ll be like a full online course except I’m gonna just make it an extremely good value and just make it available to premium members of the app, so whether it’s just getting CPD, finding the app in one place with all its content, being able to download the episodes and the videos to your device, being able to access the notes that come alongside the new episodes, or you want to get access to exclusive content, my commentary, please do subscribe to the app downloaded on iOS and Android, the download is free, you can actually use Apple free as well, it’s really functional really good. But to get the real juice, if you’re a true onion chopper, then check out Protrusive premium. And I look forward to helping you in your journey of dentistry. [Mahmoud]
So yeah, I’ve got this patient here. And when you look at the cast, you’ve got the upper left second molar. And it’s sort of rotated a little bit buckling, which you often see which means the palatal cusp is hanging down quite a bit. That is the centric relation contact point or point of initial contact in centric relation when the patient closes. And it’s the upper second molar palatal cusp against the lower first molar distal marginal ridge. And if you can see the photo, you’ll see that actually, when they are at that CRCP, the space between the other teeth is almost two millimeters. Now, this kind of patient scares me, if I see this, I’m automatically thinking. Worst case scenario is I’m going to lose all of that space, I’m going to lose a hole two millimeters. Now, I usually take about a millimeter and a half off of the occlusal. So, if I do that, and I lose two millimeters, I’m still going to have another sort of two and a half millimeters I need to take off to actually get the clearance I want. So if we cycle through the images, what I’ve got here is, this is how the patient would present to you. So this is her in her MIP. This is the bite she knows. Okay, so she comes in all her teeth touch. Yeah, upper seven is sort of in midair a little bit and it’s fractured. We’re thinking about putting an implant in the bottom where we think I’ll go crown this tooth for now, you do your screening. And I had to put a ton of leaves in at the front because she’s got a little bit of an anterior open bite. And lo and behold, that upper second molar is my centric relation contact point. And if you could look all around the arch, that is the only tooth touching by a mile. None of the other teeth are even close to touching. So that’s why I get these models because I want to know what’s going to happen when I prep that tooth. [Jaz]
And so do you get this you know, do your face bow and get this mounted on a semi adjustable articulator? [Mahmoud]
Yep, upper and lower impressions, face bow because you want the upper cast related as closely as possible to where the condyle is, and centric relation bite records. And then so once I’ve got the casts, I’ll prep the upper second molar on the cast. So I’ve taken two millimeters off the occlusal. Okay, but these casts are still being held in centric relation. So once I undo the pin, and I close the cast together, you can see the teeth close back into MIP. And look at my clearance, I have zero. So in fact, in fact, the only tooth touching is still that upper second molar. So really the condyle might not see it fully. But even if it goes most of the way there, I’m going to lose all of my clearance. [Jaz]
For those listening right now, I mean, Mahmoud’s shown very beautifully here, he’s chopped that molar good to three millimeters, and the patient’s now able to bite together as before, but also still pretty much biting on that mesial of that second molar still. And classic is a great way to show on the models, what you may have experienced. And that’s why you’re listening watching his podcasts. And that’s what happened. That’s a great visual. [Mahmoud]
Yeah, so there’s two consequences to the last tooth in the arch syndrome and possibly A) you lose the clearance, which will look something like this. But worst case scenario and patient with big shift is you end up destabilizing MIP, meaning the lateral pterygoid no longer knows what to do, and the patient cannot find their habitual bite anymore. And in this case, once I’ve removed enough off of the second molar, so I had to remove another two millimeters to simulate getting enough occlusal clearance. The patient is only occluding on their first premolar on the other side. [Jaz]
But that will be the new centric relation contact point, righr? That new point of contact is now that, yeah, yeah. [Mahmoud]
Correct. Now, I’m not saying that’s definitely going to happen. But in order to properly inform the patient, I need to be able to tell them that A) this might happen, meaning I need to take more off the tooth and B) if your bite changes, it could end up looking a bit like this. And they’ll be like, ‘Well, I don’t, I can’t chew on just one tooth.’ Like I know, which means you might require more treatment. What that treatment entails, we’ll discuss. But the important thing is it’s not, you know, it’s not up to us to really decide what to do. It’s up to us to inform the patient of what their teeth and their jaw relationship are presenting us with. And for them to choose what option best suits them. [Jaz]
And so what options did you give to this patient? The tooth you know, it’s desirable to restore that tooth, but there’s a higher risk for this last tooth in the art syndrome and you’ve been wise and you’ve done your screening up ahead and even informed the patient and you’ve gone to the trouble of you know, mounted cast and to actually create these beautiful visuals. So in the level of informed consent here is amazing. So how did you actually manage her? [Mahmoud]
So with this too, you know, the options in this case are, you know, that tooth itself, luckily, is endo treated. So we don’t, aren’t worried about pulp but we’re going to need to prep more. Now, in this case, I’ve got space, if I didn’t, what are the other options? So I could reduce the opposing? Or I can- [Jaz]
So you said you meet, you got space? You mean enough height of tooth? [Mahmoud]
Yes. She also by prepping even more for if it’s an old lady, you’ve got enough. [Jaz]
Still going up retention form? [Mahmoud]
Yeah. And if you’re onlaying it, you’re relying on your adhesion. It depends what you’re doing. [Jaz]
So it’s still restorable? Still restore. But despite three millimeters of adjustment, the tooth it was still restorable. [Mahmoud]
in this case, because it’s an upper and it’s maybe slightly overreacted. [Jaz]
That’s not always going to be the case, if it’s a lower might be a different story. And then you’re having the discussion with the patient of, is this even viable? But ultimately, once you’ve got this information, you need to present the patient with options, and the options are going to be do nothing. Or how can we gain more space for, because you’ve got two problems, remember, you got the losing occlusal clearance, and you’ve got the bite changing. So the options for losing occlusal clearance is prep the tooth more, prep the opposing, do ortho and move the teeth, create more space, or open the vertical and restore more teeth. Those are really the only options. Yeah, apart from- [Jaz]
But even then Mahmoud, like just just discussing with you like it’s not written and we’re talking about risks here, it’s not written that it’s not guaranteed that the bite will change. So you know, you do that, you know, your initial 1.5 millimeters, right? And, you know, let’s say you get the patient bite together, you might find that the muscles are able to go back to their usual MIP. And then in this case, you got lucky. But it’s all what this episode is about is identifying that high risk patient, and then having this exactly as conversation and knowing your options ahead of time, and hope that they won’t happen. And then that, you know, just won’t put it out there that okay, it’s not guaranteed that this will happen. It just could happen. [Mahmoud]
Yeah. And that’s, even if it does happen, it didn’t happen all the way. So I don’t think that most of the time, you will lose all of that space, the condyle, let’s just see a little bit until it gets to the next point of initial contact, right? And that’s going to procline lateral pterygoid. So the condyles might see a little bit, but not all the way and you haven’t lost all the space. In which case, it’s fine. But the question is, what if it does? So, you prepped. Now, once we discuss the options for the space, or the lack of, then again, you got to just mention the fact that the bite might be completely different. What are the options there? Well, like you said, already, most of the time, the patient will adapt, and most of the time, it will be fine. But if it isn’t, you need to be able to explain to them that I might need to adjust your bite. So you’re looking at equilibration. Alright, so you’re looking at adjusting the contacts until more teeth meet in that centric relation position. [Jaz]
And please don’t do this if you have no experienced, you know, don’t go around chasing blue dots, please. Right? Basically, as you listen to two guys on a podcast, telling that there’s an option, okay, this is something that you need some sort of training and experience with. So, Mahmoud, you’re stating, calibration is an option to manage the funky bite that the patient may have. [Mahmoud]
Yeah. The other two options being ortho, or again, opening the vertical and reorganizing occlusion. Now, we have a few things working in our favor, that usually mean this. This is why we don’t see this every day, you don’t see it every month is A) like we said 90% of people that have a shift, that shift is under a millimeter. The other people that have maybe a slightly more elevated risk, still have enough context around where that centric relation contact point is to pick up the slack, essentially, and re-establish a new MIP or the same MIP just with a slightly different slide. But also, I haven’t really sort of you know, I don’t have any proof of this. But in my head, I’m thinking, especially us here, we tend to do indirect restorations on teeth that have broken quite severely in a way. Now we generally don’t tend to, you know, put indirect restorations on teeth that haven’t had a cuspal fracture. Now, what are the chances that the cusp has fractured because it used to be the centric relation contact point? And that patient whenever they hit and slide have overloaded that cusp and then that cusp fractured. So in fact, what’s happened is that patient has lost that central relation contact point before they even walked in. And you pick up leaf gauge, you put it in centric relation somewhere else because well, they broke the cuspal used to be the centric relation contact point then you’re going to crown the tooth, and you haven’t changed anything because it all happened once that tooth broke. So I think that’s partly why we maybe don’t see this as often as we do. So this sounds like okay, well, this is not really going to happen to me or maybe it’ll happen once or twice in my career. [Jaz]
But when it does happen, it’s a big deal. It’s a big deal because usually you haven’t preempted it. Yeah. [Mahmoud]
Yeah. And that’s why it’s called Last Tooth in the Arch Syndrome like making it sound like really dramatic. It sounds horrible, but if it’s happened with all this sequelae of you losing space and bite changing it’s, that is a big deal. I mean, this patient that might be looking at ortho might be looking at a rehab, who’s paying for that? Chances are you. So for two minutes screen that you can do. And once you get good at it, it’s really, really quick, just by yourself that peace of mind and being able to inform the patient and gain proper consent, when you’re restoring the terminal tooth, or maybe the one in front, that two minutes is worth it, in my opinion. [Jaz]
Well, before we talk about some strategies of prevention of this happening in those high risk patients, let’s address that poor guy or gal who’s joined this podcast now and then thinking, ‘Oh my god, I just discovered this thing called Last Tooth in the Arch Syndrome.’ Mrs. Smith is like totally pissed off at me, what the hell do I do now? And they send the patient home, they just put some composite on like, some bond or something just to seal the tubules maybe. And they’re like, ‘Okay, I have no idea what to do now.’ You, I know you went over the options, but any advice you can give to that dentists has joined us? [Mahmoud]
Okay, so if you’ve already had the condyle seat, and as long as when you put your whatever it is you put on your bone, your composite, you haven’t re-established a new centric relation contact point. So you haven’t put it in high, I would wait and see if that patient develops or, you know, adapts to the existing new occlusion if you like, all right? And then assess from there. If I would do the screening again, once they come back after a few weeks, do the screening again. Chances are you’ll find that their centric relation contact point is on a different tooth now, because you’ve prepped the old one off. And if it is on a different tooth, and they are comfortable, and they have a stable MIP, then you’re back to square one. They need to assess whether you can still prep the tooth or not. Is there enough space? If there isn’t? What are you gonna do about it? Again, it’s a discussion with the patient, explain what’s happened. You tell them what the situation is. And then the options are kind of like what we discussed, because you need space. So either you’re going to prep the tooth more, you get to prep the opposing, or it’s ortho. [Jaz]
Or I mean theoretically speaking, Crown Lengthening to actually give yourself more retention form, whatever, but it’s very difficult to cram everything and applications and stuff. So may not be a real world option. So yeah, fine, that’s good. But let’s say we have found the high risk patient, but in the real world, we’re not all as meticulous as you Mahmoud. We’re not going to get our face bow out and do bounded cards and stuff. You’re too good with that. So what are the strategies, the top hacks, the sort of top secret hacks that we’re going to share with everyone, watching, listening to prevent this being an issue, even those high risk scenarios? [Mahmoud]
Okay, so I’ll come to this bur, just caveat that a little bit, I want to differentiate between sort of the low to medium and the medium to high risk, I think someone with the scenario we saw were, when they were sitting on the centric relation contact point that the vertical changes almost two millimeters. I don’t know that I would use a hack because I would still be scared. I think it’s the ones that are sort of in between where the you know, you can see a little bit of space you know, millimeter and you know, a millimeter between the teeth and you think okay, there is a good risk, they might, you know, shift a little bit. There’s two things I would you know, consider my personal favorite is before I numb the patient before I do anything, I’ll get a triple tray. For people that don’t know, a triple tray is like a quarter inch tray and it’s flattened, it’s got a metal handle and like a mesh on it. And the idea is you put your putty on the top and bottom of it, then you squirt your wash over the prep and you actually put it in the patient bites on it. So there is a called triple trace because you’re capturing your prep the opposing and the bite all in one go. Now what I do with it is I put bite registration material on both sides, put it in I get the patient to bite together in MIP. Right? And it’s critical that once you’ve done that, let it set, take it out, and put it up to the light. And you want to see pinpoint holes where the light is coming through where the patient bites into MIP. The reason is if there aren’t there then they haven’t bitten improperly and maybe the bit of metal going around the back is in the way or something like that. [Jaz]
Okay, but Mahmoud, why use a triple tray, why not just squirt in bite reg material on its own? Because essentially just capturing half side bite. [Mahmoud]
It’s just easier to handle because I’m going to be taken in and out just fine like just a piece of bite reg is maybe a little bit more. [Jaz]
Easy to hold. A bit more nurse proof, I get it. [Mahmoud]
So once I’ve done that, and I’ve got this bite. The key with that is that bite needs to stay in the mouth at any point that the patient might bring their teeth together. So it’s in while I’m prepping and it only comes out when I’m doing my, so, it’s in when I checked my clearance. Alright, it comes out when I’m doing my scan or my impression because one point I think we haven’t mentioned, if when you’re dealing with last teeth in the arch, always take full arch impression. I know in scanning you might get away with it a little bit more but you know paranoid so full arch scan or full arch impression. The bite goes back in afterwards. The bite is there. One, I’m doing my temporary the I want I’m checking the conclusion on the temporary. And the reason this can work is basically it’s preserving or trying to preserve the programming of the lateral pterygoid. So those engrams that are telling us to ptreygoid to pull the condyles down a little bit, that to be able to get into that bite that programming has to remain. But also, all centric relation shifts into MIP. While at least most of them are not like straightforward, okay, there’s usually a lateral component to it as well, meaning that bite can hold the mandible for and stop it moving laterally, which again, hopefully means you don’t lose the shift. Yes, I learned this trick from lino chi a while ago, he’s got a very interesting name for it, if you if you look it up, [Jaz]
You could say girlfriends. [Mahmoud]
And he calls it you save your ass bite. [Jaz]
I told my nurses, ‘Can I get an SYA, please? And they know that, they know I need my bite reg for one side. So that’s, that’s a good way of doing it. The other way, which I do digitally is in that in that low to medium risk patient is you scan the both arches in a preprep. So you do the preprep scan, so you get the unprepped teeth, both opposing and the working. And then you scan the bite from the beginning and said, and then that way the lab get the pre-operative anatomy and that anatomy is okay. It’s acceptable, Then they can copy the features into the final crown and hopefully not disturb the balance. But also we’re getting the bite array. So at no point will the patient be encouraged to bite onto their prepared tooth, you can actually just get them to bite when they got the temporary in place. And hopefully you’ve minimized the risk. And so the more primitive version of that, you know, 10 years ago would have been just make sure the patient doesn’t bite together, just make sure the patient doesn’t bite together at all, keep the patient’s mouth apart at all times, basically. And then that was the other way of doing that. What do you think about those ways? [Mahmoud]
Yeah, I mean, it does come down to whether or not you sort of want to preserve MIP, or are you trying to preserve the slide? So the island prep the, you know, scan the tooth prior and sort of copy the anatomy, or things that are trying to copy the or reincorporate the slide. And, you know, in a patient who doesn’t show a ton of wear, or you know, as well, we’ll cover certain things in hopefully on the course, in terms of identifying patterns of wear. You know, someone who shows excessive wear on the second molars, but virtually nowhere else may be someone who slides into their centric relation, and grinds. Now, if they do that, and you see evidence of that, and then you replicate what was there before, you might find that your restorations are being overloaded. And whatever broke the tooth, might well break a restoration. So I haven’t been brave enough to try the island prep, which is, I believe you’ve tried it. [Jaz]
Yeah. And so just to briefly describe it, you mock up that contact, the slide, the centric relation contact point or point of initial contact. And then because when you wash the tooth, you prep the tooth, that red marker, blue mark is going to go wash away. So you put a tiny bit of bond on it to preserve that marking the colored mark, you prep the tooth as normal, but you preserve that contact area on the tooth. And then you do your impressions and bite reg as normal and it’s over to a lab. And what the lab will do is a lab will actually prep it away. And they’ll make a little Duralay coping, and then they’ll send the crown the properly made crown and the coping to you. And so then I just put the coping back on the tooth, I prep away that little sticky outy bit which was the slide if you’d like and then my crown is now going to seat. The interesting thing that happened, Mahmoud, when I did this technique is the patient came back a few weeks later, with a hole in their zirconia crown. I’ve never seen this. Can you imagine a hole in the middle? There’s a chronograph. So what had happened is that I must have prepped a little bit too much on the island. Okay? So now where the crown was had the, you know, 40 microns of cement space everywhere, in that one area, there was maybe, let’s say arbitrarily 120 microns of cement space in that one area, right? And then I didn’t put enough cement either. So, you know, when mistakes happen is compounding of errors, not just one error, right? So I must have not put enough cement. So there was cement, cement cement everywhere. And underneath that a Zirconia where the island was, was air. So it was Zirconia-Air-Prep wherever else was Zirconia-Cement-Prep. And so that’s what how my technician and I came up with a conclusion. So you had to hear again and make her a new crown. Interestingly. So that was my experience. So just thought I’d share that with you. [Mahmoud]
Oh, that’s, it happens right? That’s the thing you know, you try your best and stuff will still come back to bite you. [Jaz]
The last tooth in the arch did not bite me at that time. So yeah, that’s the another way of doing it. Anything we’ve missed you think? [Mahmoud]
I think the most important takeaway messages are screen for it. It takes two minutes. Have the conversation with your patient. And, you know, this may have sounded like a really depressing lecture where, okay, I’m never going to put up second molars again, because your bite’s gonna change the patient’s gonna sue me 95% of the patients are 95% of time, this is not a problem You’ve probably been in this situation and just crap the next half of the it because he thought, okay, maybe that bur fit or thought or, or whatever. And chances are this is, you know, this has happened time and time again, you haven’t noticed. So I wouldn’t be too worried about it. But now that you know, it’s easier to describe and then have the conversation with the patient. Because if you don’t, and then you do get caught out, you’re going to be feeling really silly that you listen to podcasts and certain do it. [Jaz]
That very true. And I think just want to wrap up by saying that even those, you know, we start screening and get start getting good at the leaf gauges, you know, gives you it opens up so much in the world of occlusion and treating more teeth and moving out of single tooth dentistry makes you think whole mouth, right, and then that’s when dentistry becomes more fun. So, you know, start screening your patients anyway, every time you’re doing suspect restorations where you know, this, this could be a phenomenon, even though it’s gonna be rare, it gets you into good habits of screening. And then you know, sometimes it’ll be like a low risk or medium risk. And you know that, ‘Hey, from my risk assessment, I might lose a half a millimeter space here.’ So you know that the worst case scenario here is you can just prep half a millimeter more, and if your tooth can can take it, then you’re at peace. But if you find a really challenging dental scenario, but more importantly, that dental scenario is on a not challenging tooth, but a challenging person, a challenging human, that having come in or just you dread conversating with this patient, then the best thing about being a GDP is the ability to cherry pick. Now, because you’ve been smart, and you’ve done your assessment, and you know that, okay, there’s gonna be a full mouth case here, I don’t want to just deal with this angst with this patient, I can’t be bothered with this, say that you’re really complex pace, your bite is really screwed up. Here’s a prosthodontist I don’t like and ship them there. Right? So, you know, I’m just saying screening is a wonderful thing. So if there’s anything you take away from this episode is screen. And then you can choose way on treat that case, and most of the time, things will just sort out. [Mahmoud]
Absolutely. The flip side of that is if you are comfortable treating more complex cases. And now you’ve discovered how to screen for this. This also opens up the area of you having the discussion with the patient of you know the other way to do this, because you’ve got plenty of other teeth that need restoration, should we start thinking about maybe long term comprehensive treatment? So that opens the door to have that discussion. And maybe you’re able to stabilize that patient, and treat more teeth, do more comprehensive fun denstistry on someone who needs it. And it’s all come about because of this one broken molar. And you’re doing your best, you know, to try and treat the patient, you know, as best as you can. And you’ve discovered this issue and it just opens the door for a natural conversation to flow. [Jaz]
Very well said and that patient who you are treating that compromised upper left second molar to use that example again. And you’re right, they’ve got like these MOD amalgams and leaking composites for mouth they got significant wear, multiple cracks, and they will actually benefit from cuspal coverage. And by maybe increasing the OED you can actually do quite conservative restorations that you don’t have to even drill so much, and give them a really aesthetic result as well, then it really opens up a lot of opportunities for you to start, you know, to do comprehensive dentistry. To do it, you first need to think it and communicate it. So by doing this, the more you practice communicating, it might be your 30th or 40th patient that you can you get slick at talking about it. And then you say actually, ‘Miss Smith, you know, your crown on this side was done in 1970, your crown, your MOD amalgam here was done in 1980, the dispelling was done five years ago, and you just got like a patchwork one tooth at a time. And your bites not very stable. And so you told me Miss Smith that, you know, your main thing for you is that you want to smile, you want to improve your smile, you want the teeth to look withstand time and minimize how much dental care you’ll need in the future.’ And therefore this might be a good time, if it fits in your life to consider something a bit more comprehensive, just like you said, Mahmoud, would you like me to assess you with those eyes? And if they give you permission, then do your full occlusal examination and give them some options. [Mahmoud]
Exactly. And, you know, once it comes from them presenting with an issue and you relating everything to their long term goals. It’s a very natural, comfortable conversation. That’s exactly the kind of conversation I like to have in order to progress on to complex denstistry. [Jaz]
Okay, so Mahmoud, thanks for giving up your time to talk about this very geeky topic. I know I mean, you’re super into it. Not everyone’s into it. But I think what me and you are on a mission is to make occlusion really practical. And one of the things that we’re setting up in our course is one of my aims is not to say the word McKenna receptor even once. That’s my aim, okay, because I want to show people videos and photos of teeth of dots and lines and say ‘Hey, do this, do that don’t do this, prep this and refer that.’ And that’s really the angle that we’re coming from. But who is the ideal dentist out there that are course OBAB occlusion basics and beyond is gonna benefit? [Mahmoud]
I know it’s such a cheesy answer but really we are aiming for it to appeal or serve as many that’s it for but if you are interested in sort of taking on more what are you’re interested and taking on more complex cases or whether you choose to do the simple cases, but do them really well and really predictably. And you’ve always thought that the occlusion just sounds a bit too confusing. It sounds a bit too abstract. It’s, you know, it’s not, it’s not something I can visualize, it’s not something I can, I can really see in my mind. My aim, even though I’ve said my kind of receptors, maybe twice, sorry, lectures, but it comes with pictures. And, genuinely, for me, personally, I’m a very visual person, I need to see how things work. And once I can see them, I can extrapolate. So that’s the idea behind how I’ve sort of we’ve structured the courses, making it really tangible making it really something you can see how it works and understand it and then apply it to all the different situations. [Jaz]
Because Mahmoud’s made some really cool videos and photos series of you know, articulators step by step by step by step. And if for those of you join us for the video part of this, if you actually saw when he prepped that tooth and how it seated, we look on YouTube stuff, you will only find cartoons of that, you know, he’s actually done models, and this kind of visuals that Mahmoud’s got throughout the entire course. So we kind of split it in half, I’ve covered half, Mahmoud covered half. Mahmoud you’re into more your tools and stuff in terms of articulaters and vice versa stuff you love that I try and do as much as I can, without relying on articulates faceless I try and just eyeball it. And so we’ve got two different approaches, but we marry it together in terms of okay, fine, this is how we do it. But what we cover is why, when, okay, and when not. And that’s why I’m super excited to launch this. So guys, when we’re ready for OBAB, I will email you and you’ll hear about in the podcast. But if you haven’t listened already to basics of collusion, part one and two check it out to get a little flavor, but very exciting times ahead. And we look forward to getting this out to you. [Mahmoud]
Yeah, really, really excited about it. I think it’s gonna be something that’s really, really different to what’s out there. I really think so. And it will take you from the basics. Although it’s beyond, you know, talking about, like, you know, pictures and series and stuff like that, I’ll take you through a rare case that shows every type of wear you can imagine, and I’m waxing in the contacts one by one and you’ll see step by step and I’ll give you the reasoning of why we do certain things and how were, is all about force management. Then once you see it, and once it’s there in your head, you will you will understand the concepts and then you’ll be able to apply it to whether you’re doing you know you got just a class four or you’re doing for composite veneers or you’re doing it full mouth rehab, the concepts are the same. That’s that’s the aim really is for you to be able to do from A to Z, knowing that you ticked all the all the boxes, knowing that you understand why certain things need to be done, and not just blindly following an occlusal religion as we like to call them. [Jaz]
Yeah, I think me and you, I wouldn’t say we’re atheists, I think we’ve had lots of influences in different religions. And I don’t want to say we’re starting our own religion or anything. We’re just we’re gonna pick okay, we like this from Kois. And we like this from Dawson. And and here’s how we do is with a mishmash, and you know, why don’t you try implementing this and seeing that actually, we found that this works better in our hands in day to day, general care, me and you busy practitioners, and when the real world weapon dentistry, so that’s what we hope to share. So thanks so much, guys for for listening all the way to the end here. And we look forward to see you on OBAB. [Mahmoud]
Thank you very much, Jaz. And thanks, everyone for listening.
Well, there we have it guys, for those who are listening and some of the visuals that were amazing. Honestly, that second molar visuals that Mahmoud created, I will just go back to YouTube or the app ideally, and go back to those points. Those are absolutely golden. So hope you enjoy that. I just want to say thank you to April Whitlock and Narni Fulford. These two ladies, lovely ladies and fantastic dentists who on the app, the protrusive app in the community section actually asked for this episode. This episode was supposed to come out much later, but because I couldn’t say no to them, and they posted it in the community section of the app. I was like okay, we’re gonna do it for you. This does this episode was dedicated to you, April Whitlock and Narni Fulford.. For thank you so much for supporting the podcast in the way you do. I’ll catch you guys in the next episode, same time, same place.