In this episode I am joined by Restorative Specialist, Dr Kushal Gadhia who is one of the educators for ACE Courses. He is one of the most passionate people about Occlusion I have met, so it was great to geek out with him.
Protrusive Dental Pearl: Have you located your local physiotherapist who has an interest in treating Temporomandibular Disorders? You can find them on the following website: ACPTMD
You can download the latest Glossary of Prosthodontic Terms from Protrusive Dental Community Facebook group alongside hundreds of other papers and downloadable resources.
What we discuss in this episode:
- We discuss our reason and love for continual study in the field of occlusion
- Definition of Centric Relation (CR) (applicable one!) and why we have to rely on teeth as references
- Why is the ‘reproducibility’ of CR useful?
- When should you NOT use CR as the position to rehabilitate? 2 Good examples given (a 3rd one I suggest at the end)
- In those situations you use an arbritary treatment position, how can you ensure success?
- We briefly discuss about Orthdodontics and the controversy of whether Orthodontists should be planning from CR
- What happens to patients rehabilitated in CR position over time
- If you restore someone in CR – can you stop their Bruxism?
- There may also be an anatomical reason not to use CR which we discuss at the end
- Remember – most of our Dentistry is Conformative and in ICP/MIP – Become a GOOD conformer first!
Glossary of Prosthodontic Terms 9th Edition
Loads more episodes to come out this month to make up for February – we had the first successful ‘THE Dental Splint Course’ hosted at Precision Dental Studio in Reading.
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If You’re Not in Centric Relation, You will Die! 😉 Protrusive Dental Pearl – how to find your local ‘TMD’ Specialist Physiotherapist: http://www.acptmd.co.uk/find-your-nearest-tmd-specialist/ What we discuss in this episode: – We discuss our reason and love for continual study in the field of Occlusion – Definition of Centric Relation (CR) (applicable one!) and why we have to rely on teeth as references – Why is the ‘reproducibility’ of CR useful? – When should you NOT use CR as the position to rehabilitate? 2 Good examples given (a 3rd one I suggest at the end) – In those situations you use an arbritary treatment position, how can you ensure success? – We briefly discuss about Orthdodontics and the controversy of whether Orthodontists should be planning from CR – What happens to patients rehabilitated in CR position over time – If you restore someone in CR – can you stop their Bruxism? – There may also be an anatomical reason not to use CR which we discuss at the end – Remember – most of our Dentistry is Conformative and in ICP/MIP – Become a GOOD conformer first! Listen on your favourite Podcast Player. Direct Download MP3 file on the blog: https://jaz.dental/centricrelation Handouts: Glossary of Prosthodontic Terms 9th Edition Link to group: https://www.facebook.com/groups/protrusive Subscribe on Apple: http://jaz.dental/apple Subscribe on Spotify: http://jaz.dental/spotify Thanks again to Dr Kushal Gadhia for sharing his knowledge with us all.
Click below for full episode transcript:Opening Snippet: Evidence tells us that centric relation is a dynamic position. We are not buildings which will then remain in those fixed positions...
Jaz’s Introduction: Hello everyone, it’s Jaz Gulati again, welcome to Episode 20 got a really fun episode with Kushal Gadhia. Guys, It’s been a long time coming from this episode, but I do apologize. February was super busy. I was basically so busy setting up and finalizing my splintcourse that we delivered precision in studio in February. And thankfully it went really well. So that’s like a big, big sort of thing of my list I had to do and it was great fun doing it and I’m so happy and how it went. But now I can get back to focusing on some podcasting. I actually got so many episodes recorded with great guests, including today, Kushal Gadhia. I hope you like the title, bit tongue in cheek obviously. We’ve got so many more guests. In fact, I’m actually in a hotel. I’m in a Premier Inn right now in Cheshire and part of the Dawson Academy. And today I’ll be interviewing Dr. Hameet Grewal on rubberdam. So probably in about five or six episodes time it will be Harmeet, that’s why I’m recording from at the moment. So for those of you that Remember, this is gonna be the first episode that’s going to be offering enhanced CPD. So now you can actually get CPD for listening to Protrusive Dental podcasts. So the way you do it is I’ll post up a link in the next week or so and you can then visit Dentinal Tubules. So you have to be Dentinal Tubules member to get the enhanced CPD, answer few questions echnology aims and objectives and you will get your enhanced CPD now and from this episode onwards, we’ll try and do that for every episode so you can now get enhanced CPD. Protrusive Dental Pearl I have for you today is basically to find your nearest TMD based physiotherapist. The way you do that is I’m going to go to a website and I’m obviously put this in the show notes and actually on that note, the Facebook group, the Protrusive Dental community Facebook group has really taken off. I’ve got people like Richard McIndoe and Zak Kara on there who are making amazing so we custom screens on there that are really helpful. I’ve got other people sharing papers to someone asked question there will sort of help each other out. It’s basically not a replacement for you know, your usual big Facebook groups, but it’s a way for me to connect to my listeners and share my files and stuff as I promise you so this website I’m about to recommend, I’m going to be sharing on the group also on the website, jaz.dental, and basically it is the Association of Chartered Physiotherapists in Temporomandibular Disorder. So it’s basically ACP TMD. And the website is acptmd.co.uk, you go on there and you sort of look you’ll find your local chartered physiotherapist in TMD. And this is amazing guys is so important to have that sort of referral pathway. Physio is really underutilized from dentists as referrals. It’s incredibly helpful with people suffering from anything within the realm of TMD. And anyone who you know has an in depth discussion, we know how much I don’t actually like that term TMD. It’s a very broad term, but hey, let’s go with it. So my advice is find your local TMD physiotherapists do what I did and buy them out for coffee, have lunch with them and just learn about the type of treatments they offer. And so many my patients have had benefit from meeting the local physiotherapist I refer to now and it’s great for your learning and your patients ultimately, really benefit so that’s my Protrusive Dental pearl. We’re gonna just cuz I’m gonna get stuck in with the episode. So got Kushal Gadhia now. I hope you like it, and I’ll see the outro. Enjoy.
Kushal, we’re gonna dry dive right in and welcome to the Protrusive Dental podcast, Kush. Thank you so much for coming on. [Kushal]
My pleasure, Jaz. Thanks for inviting me. [Jaz]
And we’re going to talk about something really cool. But before we come on to that, and I do a crappy introduction of you, as I do for my guests nowadays, so Kush for to me, You are such a giving dentist, you’re obviously a restorative specialist, I believe in the specialist register for all the specialties, correct me if I’m wrong? [Kushal]
For perio, endo, prostho and restorative? Yes. [Jaz]
Yep. And what you know, I learned about you through Tubules you know, your two fellow tubulite as well, you probably run one of the most successful dentinal tubule study clubs in the world, let’s say, because I believe you’re one in, is it North London, or? [Kushal]
That’s right Northland and Stanmore. [Jaz]
You guys have like, you know, waiting lists here to turn people away every time. So I mean, that just speaks volumes about you and the environment that you’ve created your practice. And obviously, with the ACE courses, which I’ve been I’m part of the alumni what you guys have set up there is just phenomenal. So you are someone who is a massive inspiration to me and all dentists. So what would you like to add to that description? Please tell everyone where you work. [Kushal]
I’m just a dentist. I have a passion for dentistry. I’ve had this since I was an undergraduate. So I’m nothing exceptional, but constantly striving to do the best I can. I work part time in hospital and part time in practice, referral practices. So that’s how I split my week and a couple of days teaching every month. So that’s me in a nutshell. [Jaz]
Awesome. And are you allowed to say in public whether you prefer practice more or hospital more? [Kushal]
I prefer both of them. Because one keeps me real, which is the practice setting, you know, time is money. And practice allows you to make sure your treatment plans are not lengthy as sometimes they can be in hospital. But on the flip side, the satisfaction of working in a hospital setting, treating some very complex cases, not as much oncology I do now, but from cleft cases, to trauma to hypodontia, to [ ? ], any congenital deformities, and to see these patients from a very young age, sometimes going all the way into adulthood and appreciating not just dental outcomes, but life in general, that keeps me real in that sense. So for me, having trained in an NHS background, giving back to the NHS, seeing those patients, treating those complex cases, and feeling that love from that is, you know, you won’t compromise any day for any value of money. [Jaz]
That’s amazing. That’s really good. No, no, it’s great that you have your sort of foot in each, you know, practice and hospital. And I think it makes you a great clinician you are and that you know, you have so much to offer. So one of the favorite things that we mean, you love discussing about I learned about how passionate you are about occlusion when I came on the three day ACE courses, which was phenomenal, by the way, if anyone’s thinking of doing it, and I want to speak to you on the podcast about the very funny title that we came up with was, which is if you’re not in centric relation, you will die. [Kushal]
Yeah, I remember you sending me that. And I love the [inaudible] one on that. So I think these [Jaz]
and it’s 100% true, right? It’s 100% true. If you’re not in CR, you will die. [Kushal]
Yeah, well, it depends on the scenario. But not every case needs to be in centric. I think there’s this myth that every case has to be in centric. If you don’t, then everything you do will fail. There are cases when we don’t treat in centric, but I am sure we’ll discuss and elaborate of this. [Jaz]
That’s exactly I want to touch on these points. So the mean, the first thing I want to say to you know, for the benefit of my listeners is as a young dentist, which obviously I’m still young, I suppose is when I qualify, newly qualified or when I was a student, I found getting my head around centric relation, very tricky. I really struggled with it. And now that I feel I know it to let you know to where I am my career now compared to where I was five years ago, let’s say. Now that I am much more confident with these definitions and the clinical application of it, I can now look back and think you know, I was really over complicating it. And I think that’s what everyone does. And I think part of the reason why everyone over complicates occlusion and definitions and centric relation is because the bloody definitions keep changing, and the terminologies keep changing. [Kushal]
Definitions keep changing. We don’t get taught occlusion in the depth we should be taught as undergraduates. And sometimes it’s taught not in the easiest ways to understand and then we sort of carry that weight with us when we become dentists, and then come across people who may have different opinions of occlusion. And it’s such a interesting topic. But it has been not that well taught that it doesn’t become of that much significance. Yet, from a clinical point, it is the most important factor for me when I assess a treatment plan my patients, and I think it’s just keep it simple, keep it real, make it applicable, you know, we can go and talk about the science and the evolution of the whole concept of occlusion. But is that necessary? What matters to us is what matters to our patients. And if we assess them well, and we execute the plans well, what I call using the logical approach, then we will be able to provide very predictable dentistry. [Jaz]
And the reason I mean you summarize it well, but the reason why I love occlusion so much, and I love studying it and I love applying it is because for me occlusion not only brings you predictability in what you’re doing, but it also makes dentistry so much more fun. You know, there’s nothing worse than single tooth dentistry, in my opinion. [Kushal]
Yep. And then from single tooth to multiple teeth, the concepts of occlusion, the more you study, the more you will start seeing. You’ve been through the course and I keep sort of saying this, that to me, when I started developing passion for occlusion, the more I kept an eye for it, the more I’ve learned about occlusion, the more I’ve then gone and read about it, the more it sort of consolidated in my mind, and it is making it applicable, which is very, very important. There’s no point one person reading the theory and then knowing the whole book about it when they can’t translate that theory into clinical world. [Jaz]
Which is exactly why not, you know, another reason why you know, as a newly qualified dentist, I struggle with it a lot, because it’s difficult at that stage to start learning so much and applying it and of course, going back to what I said earlier about the whole definitions, if you actually look at the glossary of prosthodontic terms, their previous editions and the newer editions and by the way, for listening to this, I’m gonna stick the latest link to the glossary of the Prosthodontic terms on this sort of blog page for this episode, so everyone can download it. But yeah, it’s funny the definitions of CR keep changing. And the other definitions for example, centric occlusion has also changed definitions over the last two, three sort of editions. But if we just started about with the following, which is what is the definition of centric relation that you teach, Kusahl? And you know, why do you like this definition? Isn’t it just because it’s the latest one the glossary? Or is this the one that you find is most applicable? [Kushal]
I find this definition that I use most applicable. Before I tell you the definition of what I use. I want everyone who’s listening to this to understand that centric relation, by all the definitions, we have non looks at the position of the condyle within the glenoid fossa, yet clinically, we can’t visually see that position. So we use teeth as references, because that’s what we’re trying to see and trying to look at. So for me the definition that I’ve read and seen in Mike Weiss’ textbook, and the definition being it’s the relationship of the mandible to the maxilla, when our condyles are in its most superior position within the glenoid fossa, and when their anterior surfaces are against the posterior surfaces of the eminence. Now, I know there is variations to this, I’m fully aware of it. [Jaz]
Yeah, I like what you just said there about, you know, it’s difficult to clinically verify. And that’s why I use teeth as references. I mean, one of my mentors, Michael Melkers, obviously, coming in May, and you’re you guys, ACE crews are also coming along to us, I’m really looking forward to being a massive sort of geeky convention of occlusion if you like, but one of the things that he told me was unless you get a scalpel and actually peel back the sort of and actually visually look at the condyle in the glenoid fossa, there’s no way of actually 100% knowing for sure, and the hence why the you know, the references of the teeth coming in comes into play. [Kushal]
Absolutely. We as dentists use teeth as references, and therefore when we talk about and I’m jumping a little bit, but I’ll put this in context in that when we tell people every case needs to be restored in car or car is the most reproducible position we need to restore patients tooth. We are using teeth as references, we are not like Michael Melkers said and like I said earlier on, we don’t visually go and inspect the condyle by dissecting somebody’s mandible. And this then boils down to if you do choose to restore somebody to CR. You want those candles to be in a position that are reproducible, that are comfortable for the patient. And when you start doing the restorative work, you have to test and verify either initially using your splint therapies, your temporaries your wax up, your mock ups, whatever stages you take, but at the end of the day, we use teeth as references to ensure those condyles are in the position they should be. [Jaz]
Absolutely. So first off, first thing someone would wonder is okay, so why do we need to use CR and then the whole thing about being reproducible I think every single person listening and every single person who’s you know, final year student at dental school can you know, if an exam paper comes up, why use centric relation? Everyone always write, it’s reproducible. It was never actually made tangible to me because the way I think about it is my own bite at the moment, my MIP, my maximum intercuspation is reproducible for me because I can reproduce it right? Because my muscles have memory. So to me, I was I never really got that. And what actually made me learn the definition and learn appreciate it better was actually when you appreciate what happens when you don’t use CR in a rehab. And that gives the scope for posterior interferences, ie if you’re an MRP, and you can slide back a few millimeters to you know, where your condyle in central relation, then you can be in for example, in bruxism, you could be doing a lot of damage on that sort of back movement, if you like. And to me that made it right, Oh, now I get it in the sense that if you have a reproducible position in all head postures, then people can only brux and function or parafunction ahead of that position. So that was what were you know, and I hope that made sense to everyone. I hope you can make it clearer as well. But that was to me when the penny dropped. [Kushal]
Absolutely, it is both ways you and I assuming we both have full sets of teeth, we are able to go into a very reproducible intercuspal position and reasons behind this is we have this proprioception from periodontal ligaments cells, we’ve got muscles that are used to being in that position. But you and I don’t need rehabilitating. For patients who do need rehabilitating extreme examples being those with severe tooth wear, or the completely edentulous patients where there are no teeth to give you stable intercuspal positions or patients have worn their teeth away enough that they are habitually now beginning to posture the mandible in different directions without a stable intercuspal position then during your restorative phase of work, you have no reference points. And it is those type of cases where we start thinking we need to take patients to centric relation because it’s a reference point for me as a clinician or my technician to work to a point that everything we then construct is following the position of a mandible in such a way that things don’t change, smash or break. And then obviously the cases that do have teeth, which is me and you again, it won’t matter too much unless you go into the territory of para function. [Jaz]
So Kush I think you summarized really well there about the cases when you would want to use centric relation point, ie in those rehabilitation cases. So most cases, day to day will be confirmative and not in centric relation. But can you think of any cases? And can you tell us about those cases where you specifically definitely want to avoid using centric relation for whatever reason? So which situations would you not use centric relation on purpose? [Kushal]
That’s right. So the two big types of situations where I don’t use centric relation is from an incisal relationship position. For example, if you have a class two division one incisor patient, and you don’t take them into you’re not pursuing any orthodontic treatment on these patients, you taking them into centric relation and pushing them mandible backwards and upwards will only make the class two div one worse by doing so you’re losing more of the anterior guidance and relying on your posterior teeth for the lateral and protrusive movements. We all know that posterior teeth aren’t great for natural forces. So for dive one type occlusion not to be restored in centric relation. [Jaz]
Fine. So class two division one large overjet. If you take them back into centric relation, it will actually effectively increase that overjet make them more class two. So this is a situation where Kushal saying that don’t rehabilitate that patient in CR so you for them, we would call it an arbitrary position, right? We’d call it as an arbitrary treatment position. [Kushal]
Arbitrary treatment position. And you have to realize that if you take a class two div one into further class two div one, by increasing the overjet, you have you will not have you will have to use so much restorative material on the palatal surfaces of the upper or the incisal edges of the lower or combination of both. And yet, you will not be able to achieve anterior guidance when you create lots of overhangs. So for this class two div one time patients, of course, ideally, you want to do orthodontic treatment on them. But this is not always an option, both from an orthodontic point but also from a patient point, because there could be a skeletal discrepancy, and so on so forth. With this sort of cases where you’re making the overjet worse to what it is now, you would use an arbitrary position or habitual position that the patient is quite comfortable with, you have to also remember two things number one test, test test or you whatever you do allow time for you to test before you start jumping into bigger, indirect, irreversible procedures. But also think about the posterior teeth and incorporating long centrix movements in the mandible, which will be even on both surfaces, avoiding interferences on lateral excursions and protecting them from damage in the future. [Jaz]
My only question now to make this tangible for everyone is okay, so we decided that for for most of the cases where we will be reorganizing, we’re going to use centric relation for the reasons that we mentioned. And also it forms like a reference point. But we’re in these cases of class two div one when we’re choosing not to use CR, we’re using an arbitrary treatment position where the mandible is a little bit further or the condyle is a bit further ahead, then how can we you know, make this reproducible for that patient? ie as a reference? It becomes very tricky to manage this in terms of communication with a lab. [Kushal]
It does and then you’re then relying on what am I trying to restore? Is it for example, a tooth wear case where you’ve got worn incisal edges? Can we build these to protect the tooth structure? Think of it a patient who is in class two div one, how are they functioning? They clearly functioning because, they’re clearly eating and drinking and functioning as normal, except they have this slightly higher risk of posterior teeth being at risk of more breakages and having interferences and so on, so forth. So if we try and restore these patients, our primary objective is two things protect the tooth structure. And obviously secondary is to ensure that the aesthetic parameters are met. Functionality, aesthetics, and then it all goes down to the habitual adaptation of that patient. Now, for example, if I was doing a class two div one type case, I would choose my restorative materials to be of conservative nature. So I will use composite over ceramics as my first line of treatment, because I want to make sure if I do composites, I’m doing more additive work, as opposed to destructive or preparatory work. I’m not having to drill these down fit crowns, only to realize that in time, which could be in a short period of time for the patient smashing and breaking them. [Jaz]
It’s like you said, yeah, it makes 100%. Like, it’s like you said, you know, he said test test test. These sorts of rehabilitations where you’re using an arbitrary treatment position, you want to ensure that patients come toward, you want to ensure that occlusion is working for that patient. So whereas you probably always want to put your patient in provisionals in a, in a bigger case, in this particular type of patient where you’re not using centric relation, it’s even you know, just as crucial to test test and test to make to make sure that it’s working for them. So that’s great and which is the other time that you perhaps would not use centric relation, I think you’re gonna mention another one. [Kushal]
That’s right. So the second one is, which confuses everybody a lot, which is a large horizontal and small vertical slide when you go from your CRCP to ICP. Now with that, the key thing is as your mandible moves from your centric relation contact position, by definition being the first tooth contact position you make in your centric relation. That couldn’t be one tooth or multiple teeth. So going from that CRCP to ICP, the mandible moves in a certain direction usually tends to go a bit forward and a bit upward. The proportion of that forward and upward movement, the horizontal and vertical component could be either large, horizontal, small, vertical, or large, vertical and small horizontal. [Jaz]
Would it be forward and down? Right? [Kushal]
I think you’re talking about the condyle. I’m talking about the cusp tip fossa, [Jaz]
Okay. Sure. [Kushal]
..using teeth as references, so where you make your CRCP,` contact position, let’s say take a hypothetical situation, the cusp of the upper seven touching the lower seven, when that cusp blows and goes into from CRCP to ICP, because we use teeth as references the movement of the tooth, which involves a horizontal and vertical component, the condyle in itself also has a movement in it, where you have a large horizontal slide from CRCP to ICP, you want to try and avoid using centric relation as a reference point. [Jaz]
Because obviously,the same issues that you know, you have the same issues as having you making someone more class two, again, you’re technically increasing the overjet. Again, right. So that’s the way to think about it. Essentially, you’re ending up in the same scenario with the class two division one patient to make them more class two, or a patient who has that very large horizontal slide, you’re technically making them more class two by the mandible going back such a back way, and you’re having the same restorative, tough challenges, right? [Kushal]
When you go from CRCP to ICP in that slide, and you’re right, it’s where you’ve got a very large movement of that condyle, in a horizontal plane. This is very hard to visualize, or sort of hard to say, verbally without slides on the side. But I don’t want to confuse your audience too much. If we want to use somebody in centric relation as a reference, but going from centric relation to the ICP involves a large horizontal slide you will suddenly lose that reference point. So it is advisable in such cases not to use CR as a reference in these cases. [Jaz]
An interesting thought imagine that patient now would large slide and imagine that they receive orthodontics, okay? And the orthodontics was planned in their normal starting malocclusion wherever it may be maybe some minor crowding whatever right?Now let’s say that during orthodontics this patient and this this may be happening all over the world all the time you know in orthodontics, now this patient undergoing orthodontics suddenly deprograms right? And now their mandible drops back and now they’re gonna appear more class two, they’re gonna have more of an overjet That’s right. So this to me always was very interesting something my diploma in orthodontics never really touched on I always use thing you know, Surely this is important when when orthodontists are about to put these bite ramps posteriorly, right? And completely disclude everything else and now they’ll put brackets on and move everything around. There’s a chance that a lot of patients are going to deprogram and become usually always more class two than they always start out with. But that’s very few orthodontists actually planning that and doing articulate work and checking for slides. But you know, it’s an interesting thought. [Kushal]
It’s an interesting thought. Because there are two types of orthodontic patients. I’m not saying orthodontic patients per se. But there are two reasons why we have to look at orthodontics in a restorative treatment plan. So one is the patient that usually turns up to say, I just want my teeth straightened. But then there are the second type of patients are those patients were treating not only for straightening, but because they’ve got tooth wear associated with them. And this was a classic case that you may have seen in the alumni group recently. Patient is coming to the end of the orthodontic treatment, but also have associated tooth surface loss. If the orthodontist leaves them in a very in a class one perfect complete bite, canine guided relationship, which is what you would hope for you suddenly start deprogramming these patients and they’re going to class two dive one. What are you going to do to them? So we have to plan orthodontic restorative interface very cleverly. In such cases, this is not for every patient. These are patients that have got tooth wear that need orthodontic treatment before you start managing the tooth surface loss. Does that make sense? [Jaz]
Yeah, absolutely. And yes, we plan jointly when you’re treating you know, cases like this where I carry a lot of baggage and need a lot of restorative work as well. Absolutely. [Kushal]
On the flip side, I’ve seen where these tooth wear orthodontist will a very cautiously say I’ve left an incomplete bite so you’ve got enough room to restore that one edges with composite but actually, by the time I start deprogramming patients, which was an incomplete bites in a class one relationship turns into a class two div one. [Jaz]
Yep, absolutely. [Kushal]
And how do I know without going through further orthodontic work? So key point from this is.. [Jaz]
This is exactly what I meant. You know, I don’t think orthodontists in my experience and please, anyone listen to this as a different experience reach out to us but I don’t think orthodontists screen for this routinely [inaudible] [Kushal]
And I think it’s how we communicate from a restorative points. So prior to any deep bond of tooth wear cases. So by timeline view, I’ve seen a patient who has tooth wear I’ll put them to orthodontic treatment. I will plan my CR record Before orthodontic treatment starts, so I know where the patients’ condyle, and therefore the teeth are going to end up and I then have an indication of how much overjet is existing and how much of that I need to close, I will need to retest that before the debond stage because if I need the occlusion tightened up a little further, now’s the time to do it. Once you’ve debonded a patient and put them on retainers of some sort. Having to put the brackets on again is always never a pleasant conversation with the patient. [Jaz]
Absolutely. It’s a plan B begin with the end in mind and keep checking as you’re going along as you do, you know got very good communication with your orthodontist obviously. The next question want to ask, Kush is, what happens with these patients where you rehabilitated in centric relation as you’re sort of reference point as you’re where you’re going to build your teeth into over the years? What is the what is the evidence say these a know when you look back at these cases five years later, 10 years later? Because I think from what I’ve read, and what I gather is an actually do we you know, we adapt and when we’re no longer, we may no longer be in centric, ie we may introduce or develop into posture interferences as he has go by after rehab. So have you got an experience or read any good papers about that? [Kushal]
Evidence tells us that centric relation is a dynamic position, we are not buildings, which will then remain in those fixed positions. The joint, the TMJ joint is not like a door hinge. Once it’s crude, it doesn’t stay there. It’s controlled by a number of factors. Evidence tells us it is we know not even evidence but we know the neurovascular connections which will influence the joint. It is a bony component, the bone remodels and then obviously, patients’ stress, state of mind, posture, all these points will come into play and that joint will not stay in its position. We know in five years time on average, what you restored in CR will not be in CR take a classic example of the last denture you made four years ago where you did your best to take the patient into CR even if you got a gothic arch tracing. At the time of taking the jaw registration, it is very likely in 3, 4, 5 years time those dentures are not in CR and that’s a removable full mouth reconstruction by definition, the same or a fixed full mouth rehab that we do, but we’re using it as a reference and it doesn’t change on a daily basis or we hope it doesn’t because we’ve taken necessary measures pre treatment to keep it stable. And we undertake our treatments in small stages, including anteriors, posteriors, temporaries, before we move the temporaries into our provisionals and provisionals into definitives. But the key thing here is over time, four or five years down the line, the joint changes, and when it changes, you will have a new CRCP, ICP slide in a number of cases. And yes, you will develop interferences of breakages and chipping all the ceramic work or whatever restoration you’ve done especially on those patients who start parafunctioning and don’t protect those restorations with some form of a splint post treatment. [Jaz]
This is why part of my philosophy and I know you have as well is that you know what patients do to their teeth when they batter them. And then when you restore them, they’re likely to do that again. So an appliance is just make sense, you know, as an insurance, because, as you say, evidence suggests and we know their joint position is dynamic, and the occlusion will not be the same five years later. And then to have a piece of plastic to protect them. It just makes sense. [Kushal]
It does. And we have to remember, the average force on a molar tooth posterior is about 70 to 80 kilos. It is higher in paraunction. [Jaz]
Higher in parafunction, higher at nocturnally when we’re sort of not conscious not with it, then what we can achieve in the day. [Kushal]
Now that 70, 80 kilo is the average weight of an adult human being. Try and sit human being on a molar tooth every day for prolonged periods of time. What’s gonna happen? [Jaz]
It’s crazy when you think about it actually. The next question I have Kush for you. And where we’re coming up to the last few is an interesting theory, you know, that used to be popularized by certain dentists and whatnot, is that when you restore someone into a CR, that you might actually be able to stop their bruxism, because actually the only reason they’re bruxing is because they’re trying to rub away that interference. Okay? So I don’t know if you’ve ever heard this theory before I heard it when I was a student from certain dentists and certain sort of things are I’d read, I now know what the answer is to that. But please, can you enlighten our listeners about this theory? [Kushal]
So it’s interesting you say this, I don’t believe that taking somebody to CR will stop bruxism. And if I had to give an answer in one sentence, I would say that I can stretch to the other end and when I see my four year old niece clenching her teeth at nighttime and I she’s in the room next door and I’m unable to sleep and I see the same pattern in my sister and the same pattern in my mother. Is there a genetic component involved in this? I always say this in my occlusion lectures when we do parafunction, and we go through bruxism, why is it the masseter muscle? Why don’t I wake up with my abs muscle worked out and have a six pack to think about these factors on a logical level. It’d be great if my abs were working out I would never complain about it. Here we are in a situation where if anyone thinks that taking somebody to CR will stop their parafunction, I think they need to probably update their knowledge on this topic. [Jaz]
Some historical Institute’s are used to teach this. And this used to be part of you know the program from what I read in history that this was the understanding that people had actually. I went to a lecture at the BDA, when I was a student, I was a third year student, and a guy from the States came over. And he talked about the success rate that he had in patients who had chronic temporomandibular disorder. And it’s a terrible term, because TMD is a made up of several things. But that’s the term he used, he had chronic TMD. And they were bruxism. And they’re really suffering in life. And they tried everything that actually he found that he has a one in four chance that when he puts them, rehabilitate them, in CR their symptoms will improve. And that was probably the most modest and real thing I had. So you know, he’s got an did [inaudible] and all his patients and in his website at the time was adhesion.com actually, I don’t know if it’s still up there or not. I remember this really funky American dentist. That was an interesting sort of reflective point that he actually rehabilitates his patient, he actually tells his patients, there’s a one in four chance that I might kill you. But that’s all you know that that’s such a difficult thing to test. And largely, we know that, you know, people will always brux no matter what position you put their joint in. [Kushal]
What his rehabilitation involving full mouth direct or indirect work? [Jaz]
Yes. So what he would do actually, do you know, what he talked about his protocols in his lecture, he’d actually chop off the sort of the, you know, couple of millimeters with molars that say, the back and then just put gold onlays on and everything in sort of CR, if you like, gold equilibratio, if you like, and that was his sort of method. And he had, you know, a lecture full of 1000 to 500,000 people that the BDA at the time, I was like, Whoa. [Kushal]
I mean, if I spent 10 grand or 50 grand on my teeth, I think that in itself will stop me from parafunction I wouldn’t be worried about how much damage caused to the work paid for maybe three and four, don’t worry about the money, but one in four sets, that he did. [Jaz]
Fine. So yeah, I had one more scenario where we may choose not to restore to CR. So this is a bit jointy if you like so if people’s TMJ anatomy isn’t so good, then it’s sometimes can be difficult to verbalize it, like you said earlier to someone that has an issue with their medial pole. And let’s say you can’t load them, so they can’t load their joints, then that’s another patient, I think that you would have to accept an arbitrary position, which is going to provide relief from their symptoms. And because obviously, if you load that patient, it’s gonna be impinging on retrodiscal tissue. So would you agree that I mean, but these patients is so rare, but I think if you’re going to discover another group of patients, that’d be another, someone else you wouldn’t restore the CR. Do you agree with that? [Kushal]
Yes, I agree with that. And you got to obviously do your load testing on these patients before you start rehabilitating patients in CR depending on the audience that will listen to this they’ll either come out very confused thinking about what the media pole and retrodiscal tissue and CR and all these terminologies but I’d like your audience to take away one thing which is if you’re new to this game of occlusion or haven’t got too much of an understanding of occlusion, please don’t get flustered by it. You have to understand that when I was an undergraduate, everyone told me you have to restore every case to your centric relation, or at the time they were calling it RCP and RCP is now very old terminology. No one should be using it, it means the condyle’s in a very different position to being in CR. But we mean the same, we all mean the same, it has to be in reproducible position. But there are cases where we can’t restore patients in CR and as Jaz mentioned, there are cases where you, when you put patients in CR you will develop pain in the joint because it’s putting pressure on your disc at the back. And then the other two cases that I described, one of which is a class two div one or the third one being the large horizontal slide. So if I was trying to summarize this in a simple way, you have to keep your eyes open that not every case needs to be restored in CR. [Jaz]
That’s brilliant. And I think I really like what you said there that occlusion can be quite a daunting confusing game, I’m still develop my knowledge all the time with this as a passion that obviously it’s a part of the density which I’m really passionate about, but everyone has their own journey and I suppose you have to spend time in the dirt and what I mean about that is everyone where you are in your journey, in your undergraduate learning or where you’ve qualified and you’re sort of going to courses and you’re developing your knowledge, you have to do your time you there’s no shortcut, you have to reflect, you have to read Dawson’s book, you have to find mentors who will help explain break cases down for you, you have to go on case courses like you know, Ace courses or [inaudible or several other courses that are out there that help us to learn more and more. So if someone’s feeling like Whoa, I really didn’t get what they said there and I can completely if I went back four years ago and listened to us talking now a lot of what we discussed would have gone over my head but like you said Don’t be disheartened because everyone’s on a journey and to keep striving and actually do the work. You know, there’s no shortcut, you have to fail. You have to reflect you have to keep updating your knowledge, spend those hours learning, listening, reading, so I think nowadays people want the information or want to know something and get on with it ASAP. But it took me years and I think that’s about right. It should take you years and as long as you’re improving getting better and developing knowledge as the most important thing. [Kushal]
That’s right. And we have to understand when you get your basics right, which is from an occlusion point, and Sorry, I’m diverging from the current topic of centric relation Jaz. [Kushal]
No, no, please go for it, please. Yeah, this is what we’re wrapping it up. Now. And this is a good point to bring in. Because obviously, we’ve just given we’ve discussed CR, but what you’re saying now is so important. [Kushal]
What I’m trying to get across is 90%, if not more of our day to day dentistry happens in intercuspal position for the dental patients, we that a simple filling, occlusal MO, DO, MOD, whatever extension it is, direct, indirect dentistry, we do it in our confirmative intercuspal position. If occlusion baffles you, just get your single unit or multiple unit conformative of dentistry and master the principles in that. This topic of centric relation when we’re trying to move the mandible and the condyle needs most reproducible position, starts to come in when you start treating the bigger cases. So this may not apply to your day to day dentistry. But the understanding of it, especially when you start doing the bigger cases is of paramount importance. I hope that sort of puts things in context, because people start thinking of CR when they’re doing their day to day dentistry. And it doesn’t apply in whatever form or shape. You have to assess where the contacts or CRCP contact is, don’t get baffled by the fact that we’re discussing such a topic, this is very likely the next stage in your career if you’re not working outside of the remit of conformative of dentistry, and it’s when you come to start doing reorganized approaches when you need to start making this jump and learning CR. [Jaz]
That’s brilliant guys. Kushal said it loud and clear, then you know, become a good conformer first and it become a fantastic and actually properly conforming, you know, don’t just look at your sort of work and then restore it as long as everything’s balanced is fine. As you truly try and conform to the best of your ability and do multiple units slowly over time, get comfortable with that. But again, conforming and only when you get to the bigger cases, like Kushal said, that’s when what we’re saying will apply and maybe three or four years later, you’ll listen back to this episode and think oh, okay, that sort of makes sense now wherever you are in your journey, just do the best you can and strive to get better. So Kushal with that. On that vein, thank you so much for giving me your time to talk to our listeners to learn more about centric relation and how in cases where you should be using and where And importantly, where you shouldn’t be using it. And of course, we’re all gonna die one day, so especially if you’re in a CR or not, we all gonna die. [Kushal]
We’ve got to be real in life. [Jaz]
Kushal I thank you so much, mate. [Kushal]
My pleasure, Jaz. Thanks for inviting me once again.
Jaz’s Outro: Thank you guys for joining me back on episode 20 which has been a long time coming. So thanks for your patience. Got so many great episodes coming up probably like once a week now from now on. A lot of these there can be video episodes as well. So I hope you enjoyed that. Catch you on the next one.