[OCCLUSION MONTH] Vertical Dimension – Don’t Be Scared! – PDP197

Protrusive Dental Podcast

Treatment Planning Symposium 16th November Hybrid event: https://www.protrusive.co.uk/rx

Are you still afraid of raising the Vertical Dimension? You cannot break free from the shackles of single tooth Dentistry if you don’t get comfortable with vertical dimensions changes in Restorative Dentistry.

https://youtu.be/Nb-LTyzRKuU

Watch PDP197 on Youtube

In this episode, Dr. Jaz Gulati and Dr. Mahmoud Ibrahim simplify the complex topic of increasing vertical dimension.

What is a safe limit of increasing the vertical dimension?

They cover the essentials of joint health, muscle stability, and the importance of centric relation (does it actually matter?)

Protrusive Dental Pearl: Use Duralay copings for guide planes to ensure stable dentures with a single path of insertion. While eyeballing the prep can be challenging, he suggests requesting acrylic copings from the lab for precise preparation. He explains that technicians survey models to identify undercuts and determine the path of insertion, and instead of manual prepping, he advises using lab-created reduction copings and acrylic jigs to simplify and accurately guide the preparation process.

Need to Read it? Check out the Full Episode Transcript below!

Highlights of this episode:

• 02:05 Protrusive Dental Pearl Acyrlic Copings for Guide Planes
• 03:57 Dr. Mahmoud Ibrahim’s Introduction
• 06:05 Personal Experiences with Vertical Dimension
• 08:45 Challenges and Techniques in Vertical Dimension
• 14:17 Clinical Considerations (Restorative Dentistry) and Research
• 21:15 How to Assess OVD Loss?
• 24:35 Factors to Consider in Increasing the Vertical Dimension
• 28:41 Treatment Planning: Orthodontics vs. Restorative Management
• 32:21 Assessing Cases for Vertical Dimension
• 34:39 Joint Position and Vertical Dimension
• 39:47 Occlusal Appliances Prior to Increasing Vertical Dimension
• 45:26 Joint Relationship
• 50:49 Reproducibility and Stability in Occlusal Planning
• 53:00 Summary and Final Thoughts on Vertical Dimension

This episode is eligible for 1 CE credit via the quiz on Protrusive Guidance.

AGD code: 180 Occlusion (Occlusal therapy)

This episode meets GDC Outcomes A and C.

Dentists will be able to:

1. Explore key clinical considerations and current research in restorative dentistry related to vertical dimension, enhancing your ability to make informed decisions.

2. Understand the relationship between joint position and vertical dimension, and how to assess and manage this relationship effectively.

3. Recall the guidelines for assessing the vertical dimension and the safe limit for this in dentate patients.

If you liked this, you will also like Functionally Generated Path Technique – Conforming to Funky Occlusions – PDP168

Click below for full episode transcript:

Teaser: But it can also help you stage treatments, right? It's a great technique to learn because it allows you then to stage those more comprehensive cases. So one of the most useful things about opening vertical dimension is gaining space for your material without having to prep teeth that they're usually already quite worn. Now that is a huge benefit for anterior teeth, but also can come into play on back teeth.

Jaz’s Introduction:
I used to be petrified of opening the bite, i.e any kind of treatment that would increase the patient’s vertical dimension would be way out of my comfort zone and it really made me worried like, is the patient going to adapt?

Are they going to get joint pain? Am I perhaps increasing the vertical dimension too much? And so for the first 18 months of my career, I was focusing on conformative dentistry. Not having to change the vertical dimension, just accepting the patient’s bite for what it is and working with it. You know, a filling here or a crown there.

And back then it mostly was small and large composites. I was still finding my feet, I wasn’t confident with indirect dentistry, and like I said, occlusion is confusing to all new grads. And I remember the first couple of cases where I started to think about this, whereby the only way I can solve this patient’s occlusion and give them what they want, be it denture or some new restorations, would involve opening the vertical dimension.

I was speaking to my principal and I said, okay, are you sure this is going to work? Is it going to be okay? What if the patient has pain? And I think a lot of you have also been through this and some of you may be in that place right now. Which is why with Dr. Mahmoud Ibrahim, we’ve created this episode specifically devoted to vertical dimension.

Look, this short episode, whilst we’re going to really make sure it packs a punch, is not going to allow you to open the vertical dimension, but it’s going to inspire you to think about it more. It’s going to give you some guidelines in terms of how much you can raise the vertical dimension. Is there a magic number?

And how is it measured? Which patient should we not be thinking about raising the vertical dimension? And which patients may need an occlusal appliance, and for how long, before we were to think about raising the vertical dimension for that patient.

Hello, Protruserati, I’m Jaz Gulati, and welcome back to your favorite dental podcast. It is Occlusion Month, it is September 2024, devoted to occlusion, and this episode we’ve got something for everyone. We’ve got something for the new grads, really reconnecting with those feelings I used to have as a new grad. And for those of you who have a little bit more experience, we’ll give you a few more ideas about me and Mahmoud record the vertical dimension to make sure we have to do as little adjustment as possible.

Dental Pearl
Now, every PDP episode, we give you a Protrusive Dental Pearl. This pearl is inspired from the last episode about digital dentures. It was a request we had in a YouTube comment. I’d mentioned these duralay copings for the guide plane. So know how we do dentures. We try to build in these guide planes to allow your denture to have one path of insertion. And that generally gives you a more stable denture, one with more retention and stability. But again, when I was a new grad, I had no idea about how to prep for a guide plane. But I’d like to share with you now how I do it currently.

And this is something that we can all do. And I think if you get your technician involved, it makes your life a little bit easier. I mean, yes, you can eyeball it. Because as long as you can remove that maximum bulbosity of a tooth, and you can really picture that path of insertion. And kind of like when you’re doing a bridge, you want the surfaces nice and parallel against each other.

But sometimes that’s tricky to do, which is why you can ask your lab to make some acrylic copings. So what’s happened is that the technician has surveyed the models, found out where the undercuts are, decided on the path of insertion along with your guidance, and instead of you just prepping the guide planes, you can ask for these reduction copings, whereby the technician has actually prepared the guide planes on the model, actually drilling the teeth on the model, and making this acrylic jig so that all you have to do is put the jig on the tooth, and it will highlight the exact area you need to prepare.

So those of you who are listening and commuting right now, if you’ve never done this before just visualize a little like a sleeve going on the tooth and now the belly of the tooth is exposed and you just get like a nice long carbide bur and shave that away until you’re flush against the coping.

If you’re watching on Protrusive Guidance app where you can get CPD as you know or on YouTube then you would have seen a visual for that. It’s a cool thing to do, especially when you have loads of guide planes to worry about. As always, as was the theme of the last episode, make sure you have a good relationship with your technician. Have a chat with them. Pick up the phone before you do this kind of work. Anyway, back to occlusion now. Enjoy the episode and I’ll catch you in the outro.

Main Episode
Dr. Mahmoud Ibrahim, my occlusion brother from another mother. How are you doing, my friend?

[Mahmoud]
I’m good, man. How are you, Jaz? You good?

[Jaz]
I’m all bunged up, as you know, with the kids getting one bug to the next bug. But the show must go on, as they say in Hollywood. And so will this educational podcast. Today we’re talking about the vertical dimension of occlusion. And I think it’s fair to say, Mahmoud, that this topic, podcast topic, when I suggest it, just scared us just a little bit, because it’s so vast, like, how do we even begin to tackle this topic?

So, what we did is we came up with some sensible topics that we think is realistic to cover in a podcast, that’s going to give a lot of value to everyone who makes, listens to this, and can take away enough nuggets to really improve their standard of dentistry. So we have a tough one. For the very few people, maybe they’ve just googled occlusal, vertical dimension occlusion, they’ve landed on our podcast, and then you, Protruserati, hello.

[Mahmoud]
Hello, hello.

[Jaz]
Just tell us about yourself, Mahmoud. Remind us about you as a clinician, what you stand for, your love of occlusion.

[Mahmoud]
Ah, yeah, so, I think I said before, I’m almost into my 20th year now as a dentist, which is actually terrifying. But, yeah, it’s been fun.

[Jaz]
You don’t look a year over 19 years, mate.

[Mahmoud]
I was expecting that, I was expecting a receding hairline. Can you see? It’s actually got me a little bit paranoid. I’ve got my like, bun cause I’ve got a midlife crisis going on. But yes, my sort of obsession, I will call it an obsession cause that’s what it is with occlusion probably started about 15 years ago. And cut long story short, my sort of area of passion and dentistry is sort of minimally invasive cosmetics.

So I’ll do a lot of direct composite work. That’s sort of where my artistic passion lies. I adhere to a lot of occlusal teachings or philosophies that we came up with and we teach together. So we’ve had an amazing couple of years of creating OBAB and lecturing around the country. So it’s been awesome, but yeah, that’s where my passion lies really with a bit of ortho thrown in because it kind of combines both those aspects. That’s me in a nutshell.

[Jaz]
Great. And the topic to cover today in terms of where to start is, I just want to share my feelings when I tap into my feelings when I was just maybe a year or two qualified. Like everything when you’re a newbie dentist is, and so right, it should be, is very much, you are conforming. So let’s just go back to basics, conforming versus reorganizing. Conforming meaning, we are not really changing the bite so much. We are working on one tooth, we are working on two teeth maybe, and we’re keeping the general features of the bite as they are.

And so, as a young dentist, that’s what you do. And then so, what I found is, when I came to a case where maybe even to think about increasing the vertical dimension, opening the bite, all these terms that we use, right, that used to scare me. Did you also have that?

[Mahmoud]
Yeah, I mean, when we mentioned this topic, we’re going to cover this topic, and you said it scared us both. I think it’s a combination of, yes, it’s a vast topic, and there is very little consensus on this topic, but also there’s a little bit of PTSD, because, at least for me, the first time I was let loose on patients was for complete dentures. I don’t know if it was the same for you guys, but that was, it was complete dentures the first thing you do.

I assume the rationale is because you can’t kill a patient with an alginate mold. But at the same time, you’re getting thrown at the deep end, the tutor’s talking to you about vertical dimension and about centric relation, and you have no clue what’s going on. You’re just about competent enough to get most of the alginate into the tray, right?

And most of that into the patient’s mouth. So it gets sort of, vertical dimension and centric relation get enshrined in your brain into this area that gets triggered and you crap your pants every time you hear the word, right?

[Jaz]
And back when you were learning complete dentures, Mahmoud, it wasn’t centric relation, it was retruded contact position, right? Shove them all the way back. So things have changed a little bit since then as well.

[Mahmoud]
Yeah, yeah. And equally, just like centric relation, some people hold it in this like regard as it’s like it’s magic, right? Vertical dimension also in some people’s view of the world holds a sort of magical place where you’ve got a path you’re going to find the vertical dimension for that patient, right?

Like it’s an immutable number and you’ve got to find it I think as we go we’ll discuss how maybe that’s not quite as strict as it must be although I do want to say that throughout this podcast. I’m going to be talking mostly about a vertical dimension on dentate patients, okay, or with a edentulous or mostly edentulous patients, it’s slightly different.

[Jaz]
And when you’re a student learning complete dentures, or when you’re doing complete dentures, you don’t really worry so much about increasing vertical dimension, because ultimately it’s in wax, and it leads beautifully to the dentate patient. Now, we have a dentate patient, let’s say the patient is worn, it’s one thing when you gain enough knowledge to know that actually, this is pathological wear, and one of the treatment modalities we may use here is to increase the vertical dimension, a. k. a. open the bite, right?

That’s one treatment approach you may use. But, to think about the downsides of opening the vertical dimension, right, is the following, right? By opening the vertical dimension, okay, some of the fears that I used to have is, will the patient be able to tolerate it? Will I cause more damage to the TMJ?

Am I going to lose control of the occlusion? These are all things that I didn’t know what they meant when I was there, but I was just worried about doing it. But the other thing which we don’t talk about enough is, if you open the vertical dimension, so let’s say the patient’s teeth are all meshing together, and they’re worn, and then on an articulator you open the pin, and so now the teeth are all apart. How do you get the teeth back together again?

Well, we’ll talk about DAHL. Let’s ignore DAHL for a minute, okay? Suddenly, you go from someone needing, potentially, 28, 32 restorations to get everything to meet together again. Suddenly now you’re looking at a huge case as someone with not very much experience, right?

So that’s why it was a scary thing because it was like a big thing. You’re now committing to treating not necessarily 28, 32 teeth, but at least one whole arch, right? So, for example, you open the pin and then you treat an entire upper arch and get everything to meet together again. The stakes are much higher, just like you said.

The fees are higher, the stakes are higher. And again, so many unknowns, unknowns. When we are learning this stuff, because it was like, whoa, what if I mess something up? What if the patient comes back and has TMJ pain? What do I do? Now, I know we can talk about how to mitigate that, and how to discuss it, but for me, and I saved DAHL for later, for me personally, Mahmoud, I’d love to know how you got into it, but the first time I increased the vertical dimension on a patient, non denture patient, was using the DAHL technique.

And this was just like two years, one and a half years qualified. And for me, this was like a great gateway drug into occlusion, right? Because you get to open the vertical dimension, but you can do it as little as six teeth, for example. And you’re like, wow, look, I just treated a wear case kind of thing, and I opened the vertical dimension, and guess what?

The patient comes back, and they haven’t exploded, and they haven’t complained of all sorts of headaches, and jaw issues, and adaptability issues, and their speech has adapted well. And suddenly you think, hey. Maybe I’m overthinking this.

[Mahmoud]
Dentists love to argue about semantics sometimes, right? So, I’ll see a case of someone’s posted where they’ve done DAHL, right? So they’ve opened the vertical dimension on the anterior six teeth or whatever. But the patient actually had some posterior tooth wear, right? And then the dentist gets crucified for doing this by people who don’t yet realize that what the patient, the dentist has done is open the vertical dimension using DAHL as a stepping stone.

But maintain the space posteriorly using composite or GI. I personally don’t like to use GIC because it wears away too quickly. But you can just use composite buttons at the back. And then you maintain that way and then you can, and then essentially it becomes a conformative case, right? You can do a quadrant at a time. So not only is it a great gateway, to doing, to increasing the vertical dimension or doing slightly more complex treatment on-

[Jaz]
And thinking more comprehensively, thinking multiple units.

[Mahmoud]
But it can also help you stage treatments, right? It’s technically, you’re not doing DAHL because you’re not allowing the overruption of the back teeth, the intrusion in front teeth, et cetera, but it’s the thought process is there, or at least the methodology is still, it’s still there.

It’s the great technique to learn because it allows you then to stage those more comprehensive cases. And even though I’m now at a stage where, yeah, I can probably do the full arch at once, I actually prefer not to. It’s just too stressful. There’s just too many variables. Why? I’d rather get the anterior sorted, put the posterior stops in, and then I can take my time, the patient can take their time, and I can just put-

[Jaz]
And either convert the right side and then the left side, or the top arch and then the lower arch, right?

[Mahmoud]
Exactly.

[Jaz]
And so I would say that one thing that perhaps you can recommend, Mahmoud, to everyone is if you’re new into dentistry and you want to delve deeper into this, find a patient with localized anterior tooth wear that is suitable for the DAHL technique and if you’re worried about tooth loss, opening the vertical dimension, then that might be a good case to obviously helping the patient, right?

There’s localized wear that needs treating and the posteriors are relatively unworn in those cases, which is why it’s such a minimally invasive and fantastic treatment modality. I know our friends across the pond may not believe in it as much, okay, based on our experience. But in Europe, Scandinavia, it’s very much done a lot and done to a very high standard, and it’s quite predictable from what we see.

And like I said, once I started to DAHL cases, and my patients didn’t implode and explode and all that kind of stuff, nothing bad happened. And I was like, hey, hang on a minute, maybe now I can, also opened the vertical dimension for my other dentate patients and I was less it kind of gave me the hunger and the bug and the confidence to go further into my occlusal studies.

[Mahmoud]
Yeah, there’s a there’s a wonderful two part series actually on protrusive with crash here about DAHL. So if you’re thinking what on earth are these two talking about go back watch those.

[Jaz]
It’s like episode 16 and 18, way back when, like 2019 or something, right? They’re very old episodes, but still very relevant. Tiff Qureshi, absolutely always got time for him. Just a brilliant person to listen to. So go back to those old episodes, they’re very, very informative. Everything to do with DAHL.

[Mahmoud]
It still applies today, so, old or not, old is gold.

[Jaz]
So Mahmoud, I want to start by just talking about, I guess the direction we want to go in is, opening the vertical dimension as a focus because there are some patients that may benefit from decreasing the vertical dimension So if you’ve got someone who’s let’s say got an anterior open bite, right and they’ve got a longer lower face height then they may get orthodontics to intrude the back teeth, okay?

And then you actually are decreasing the vertical dimension on that kind of patient. But really, the most common time that we, as restorative dentists, what we’re doing more often than not is we’re opening the bite. That is much more common. We’re thinking about vertical dimension considerations. We’re thinking about wear cases.

And, but generally in the umbrella term of changing the OVD. I’m just going to talk about three papers and we’re not going to go into too much depth about them but three papers that we recommend in our courses. And just mention about them I’ll put some of these in the resources. But one is from the International Journal of Stomatology and Occlusion Medicine it’s by Rebibo et al. And it’s vertical dimensional occlusion the keys to decision, we may play with the video if we know some of the game’s rules, which is really nice, okay?

So, nice way to do it, and it gives us a little table in there to consider, okay, at what point when we consider increasing the vertical dimension, at what points would we consider decreasing the vertical dimension? So that’s a good one, and I’ll put that in the resources. Another paper is in the Journal of Prosthodotics.

It’s occlusal vertical dimension best evidence consensus. And this one looks at over 27 articles and talks about the whole resting face high and generally the occlusal vertical dimension, a very step back, holistic approach, and that’s a good one as well. But the main one I want to talk about is the Australian Dental Journal.

It’s called Clinical Considerations for Increasing Occlusal Vertical Dimension. So once again, we’re kind of focusing on increasing vertical dimension. Otherwise, we’d be here for five hours on this podcast, talking about increasing, decreasing, resting face height, all that kind of stuff, right? And this is a review.

By Abduo and Lyons, okay? And I love this paper, and one of the things it suggests, having looked at everything, is we can actually get away, and something that Tif talks about a lot as well, is increasing the vertical dimension is very predictable, okay? Especially up to 5 millimeters, okay?

So, my question to you firstly is, Mahmoud, what have you found in your experience of opening the vertical dimension in terms of tolerance and acceptability to our patients and any side effects of patients.

[Mahmoud]
Okay, so from my personal experience, I have at most had a patient be aware that their bite is slightly different. But I’ve never had anyone complain of pain, you know, as long as the contacts are well distributed across the arch, I’ve not had anyone complain of pain or TMJ issues or muscle issues. The one thing we got to bear in mind is when you look at increasing the vertical dimension and you’re looking at a full, full denture case, right?

Why do people think that’s low risk? It’s because everything’s in plastic, right? You can just take it out, bin it, and you’re done. Why do people think increasing the vertical dimension in a dentate patient is higher risk? Because you’re usually putting in restorations, you’re doing irreversible stuff.

However, you do have one thing on your side. It’s that those teeth come attached to PDL, right? There is a study, I think the author’s name was Helsing, which is really cool. But they found that even if you increase the vertical dimension on dentate patients, they use a splint up to six millimeters. A single closure, right, a single closure could actually help them get the muscles to re adapt to the new vertical dimension.

So the patient closed once, and as soon as he opened the freeway space, if you like, or the resting position, the manual re established a millimeter and a half below the level of the splint. So while you still have PDL, your muscles can adapt very, very quickly. Okay. So we have that.

[Jaz]
Can you just make that point tangible about the whole freeway space element? So just make it a different way to just make it tangible for our younger colleagues.

[Mahmoud]
So for example, let’s say for me, if I’m biting together, okay. That’s my occlusal vertical dimension. Now, just to clarify occlusal vertical dimension, lower facial height, not exactly the same thing. Okay. Some people get that confused as well.

Lower facial height from base of nose to your chin. If you choose to measure the vertical dimension as that, then they are the same. But actually you can measure the vertical dimension using any two fixed points. One on the maxilla, one on the mandible. Okay? So, let’s say my vertical dimension when I’m closed is this. Now, if you ask me to just let my mandible hang loose.

[Jaz]
Give it a number for those listening just as arbitrary number. So we can then, let’s call that 60. I don’t know what that means. Call it a unit of 60 millimeters, whatever. Okay. Let’s call it 60.

[Mahmoud]
60. Yeah. That’s that, mouth closed.

[Jaz]
Teeth together. MIP.

[Mahmoud]
Okay. Now with my jaw resting, so my resting vertical dimension, yeah, let’s say I’m open five millimeters or whatever. Yeah, even though dentures we are trained to give them three millimeters freeway space, but it’s variable. So now, at rest-

[Jaz]
And as a rule of thumb there, just because we’re talking about this, right, so as a rule of thumb, because you said 65 here, so 5mm freeway space, which is a complete denture term anyway, right, but let’s just go with it, resting face height, you’ve got that 5mm freeway space. In class 2 patients, you tend to have more, in class 3, you tend to have less, as a rule of thumb.

[Mahmoud]
Actually, I’m a bit class 3, so I’ve probably got like, let’s say it’s 62, yeah?

[Jaz]
Okay, so you’re resting, your lips are still together, your teeth are just apart, as they should be. Lips together, teeth apart, it’s the rule of life. And now your measurement of those two fixed points is 62 millimeters. Carry on.

[Mahmoud]
Yeah. What they did is then they get a splint, and the splint opened my vertical by about 6 millimeters.

[Jaz]
Measured where? Where was the six?

[Mahmoud]
At the anterior.

[Jaz]
So measured at those, at the anterior, exactly. Because if you have it, Mahmoud, tell us what would happen if you put six millimetres of a splint measured posteriorly.

[Mahmoud]
You’d have like 18 or 15 millimetres at the front.

[Jaz]
It’d be a huge, huge, huge block at the front, basically. So, a really important thing to establish and the guideline that I talked about from the Abduo paper is that actually increasing the vertical dimension to 5mm is very safe, very predictable in restorative cases for those cases that need it, right? Is 5mm is measured at the front, okay? As an anterior reference. So, thank you for clarifying.

[Mahmoud]
So now, they put the splint in, it’s open 6mm at the front, so when I bite together on the splint, I’m at 66 millimeters vertical dimension. Yeah, as soon as I bite once my muscles readapt and then when I open and my jaw is resting I have two millimeters again-

[Jaz]
You’re 68 now. Now, there are limits here. It makes perfect sense now, but anatomically there are limits, because sometimes you just cross that threshold where now we don’t get a lip seal anymore, right? So, there’s so many things to look at, and so, now that you mention this, it’s actually a great point to just to do a little mini deep dive into the paper, because there’s a really nice table in this paper by Abduo.

It says, described clinical techniques for assessment for OVD loss. So how can we look at someone and say, hmm, this patient has lost OVD, which by the way, just because someone’s lost OVD doesn’t mean that we need to restore OVD. There’s other parameters we’ve got to look at, patient age, function, aesthetics, and we’ll come on to that.

But one way is pre treatment record. So, for example, if you’ve got some old models, which no one has, okay, but for some reason they’ve got old models, and then you’ve got new models, and you see, oh yes, I can see that the vertical dimension has decreased, and that’s one way to assess it. The other one is, and this is just what they’ve listed, is measuring the height of the incisors, okay?

Which they actually describe as a disadvantage is, it actually poorly represents the actual loss of OVD. So, think of that DAHL patient, okay? Localized anterior tooth wear, okay? That patient might have worn away their anterior teeth, acid erosion, attrition as well, and over time, the teeth have kind of alveolar compensations happened, they’re overerupted.

The back teeth are still pretty much unworn. So, whilst the anterior teeth are 50 percent worn, The posterior teeth are only 5% worn let’s say, that patient has technically not lost any, much vertical dimension at all. So you have to be careful when we’re using the incisor height measurement when it comes to actually being reflective of loss of OVD, and Mahmoud please button and chime in at any point as I read through these.

[Mahmoud]
Yeah, no, I think, I see this a lot where they’ll say a patient has localized anterior tooth wear, they’ve lost OVD. They’ve technically lost in size or height and in some patients you’ll see that the overbite gets deeper. But if the posterior teeth are still intact, then they haven’t lost VDO.

So does it matter? Well, it only matters in as much as I hardly, well, I don’t think I have ever treated anyone for a loss of OVD in a dentate patient because of tooth wear, okay? I have opened their vertical dimension. But it’s not because they’ve lost vertical dimension. It’s because it gives me certain advantages that we’ll cover later on.

[Jaz]
Absolutely. The other one is phonetic evaluation, and the thing about this is, again, it actually poorly represents the loss of OVD. The S sound is the closest speaking space that’s often used. It’s a reproducible technique, but it’s more useful in dentures rather than dentate. Patient relaxation is a tricky one because, A, it’s good because it ensures the lips are meeting and the lips are now involved in the facial planning as well, which we don’t want to actually increase, raise someone’s OVD beyond their lip seal. And that’s an important consideration, which I learned much a few years after qualifying actually, but there are disadvantages because minor muscle tension will lead to inaccurate measurements.

Assessing the facial appearance, which like you said, is a bit arbitrary as well. Radiographic evaluation using Ceph. Obviously, if you’ve got access to one and doing orthodontic planning, it makes sense, but you need additional equipment for that. And then recording neuromuscular. So for example, EMG muscle activity is another one that’s used.

But again, these devices are not often available, and a lot of expertise is required. And we don’t know how well this may represent the need for the patient to restore the OVD at all. It’s a tool. It’s a measurement. It’s objective data, which is good, and it’s accurate and reproducible. But again, they’re not often available in the clinical setting.

So I just wanted to give a little overview of how we assess the OVD. But Mahmoud, forget the paper. What do you look at when you look at someone’s dentition and you have a wear case or not? What are the factors that you use to think about, okay, this patient would need increasing the vertical dimension?

Interjection:

Hey guys. It’s Jaz again for a quick announcement. It’s that time of year again for our annual live protrusive event. This year in London the Sheraton Skyline Hotel. We’ve got Dr Lincoln Harris from Australia and also from Australia Dr Michael Frazis. They’ll be joining me on Saturday 16th of November for a full day.

Now, because you guys on the community couldn’t decide between the topic of treatment planning or failures, we combined them both into the Treatment Planning Symposium: Learning from Failures. So in the morning I’ll be kicking off showing you some my own failures and what lessons I’ve learned that I want to pass on to you. And the most unique thing about this is because I’ve been videoing my procedures for a long time some of these restorative calamities that I’ve made I’m going to reveal all. I’m going to show you all and how I actually fix them as well. that lecture itself will be worth your entire day.

Then I’ve got Dr Michael Frazis talking about his failures in the last 10 years both in clinical and in communication. And what I appreciate about Educators like Dr Michael Frazis is their willingness to share failures and talk about it.

And of course, the main event, the headline act, Dr Lincoln Harris. Last time, he was talking about de-stressing dentistry. This time he’s doing a treatment planning masterclass. We’ve actually got a live patient in store. I’ve taken the photos, I’ve got the radiographs, patient will be there with him live, and he’ll be interviewing the patient taking a history coming up with a treatment plan and communicating it to the patient live, on stage under real time conditions. And then he’ll talk about all his lessons for being an effective Treatment Planner and Communicator.

The tickets are on sale right now and they are a ridiculously low price for an event featuring two international speakers. We also have a live stream so wherever you are in the world you can catch it all live including the live panel discussion the live patient and all our lectures on the day. So if you’re local, someone in Europe, please come to Sheraton Skyline Hotel on 16th November come and network and feel that live magic.

But if you’re unable to attend, then we’ve got the live stream with the 30-day replay at a really good price. Got the early bird offer at the moment so head over to protrusive.co.uk/rx, Rx as in treatment right? So forward slash rx and the early bird offer ends this month so book your ticket now to avoid disappointment. Once again, protrusive.co.uk/x and look forward to seeing you there.

[Mahmoud]
Okay, so for me, increasing the vertical dimension comes because of usually one of three things, right? A, aesthetics. So a lot of these wear patients wants to have longer front teeth, right? They’ve worn their teeth down, they want to have longer front teeth. And what is the one thing I don’t want to do on a patient that has worn their front teeth short?

I don’t want to, once I’ve restored them, to give them a deeper overbite than what they already have. Because that’s going to put the material that I’ve put on the end of their tooth at risk. A fracture, right? Because it’s in the way of how they want to grind. So one way that you can lengthen upper anterior teeth and lower anterior teeth without increasing overbite is actually opening the vertical dimension. So if you open the vertical dimension and then you can lengthen the teeth. You can maintain the patient’s pre treatment overbite.

[Jaz]
So if they had a 25 percent overbite to begin with, and you restore those anterior teeth, you can now go to a 60, 70 percent overbite. But actually, if you open the vertical dimension, you can maintain that 25 percent overbite.

But now you’ve actually increased the vertical dimension. The downside being now that, okay, you need to think, you need to put your occlusion hat on, do more planning. If it’s not a DAHL, then you’re treating, committing to treat at least one whole arch. But this is where dentistry becomes more fun, right? It becomes more fun.

[Mahmoud]
You’ve got to remember, ortho is always on the table, right? So this becomes part of the conversation of the patient. A, do they need more teeth treated, right? If every single tooth needs treatment anyway, and the arches are fairly well aligned, am I going to try and intrude everything?

No, it doesn’t make sense, right? Opening the vertical dimension becomes a much more obvious choice. But if it’s localized to the anterior teeth, the rest of the teeth are fine, then DAHL becomes an option, ortho becomes an option, and it’s a discussion to have with the patient. Now let’s just say the sort of general rule of thumb I use, if it’s localized to the anterior tooth, where I’m just going to lengthen the teeth, One good way to think about, cause you always get asked, well, how much to open the vertical dimension? If you open the vertical dimension in the front by about as much total length, you’re going to add. Then you’re probably not going to deepen the overbite very much.

[Jaz]
So if you need to add three millimeters of length, open the vertical dimension by three millimeters.

[Mahmoud]
Roughly. Yeah. And this leads us onto the second reason or a second advantage of opening the vertical dimension, because as we know, we don’t open straight down. When you open the vertical dimension, the lower incisor doesn’t drop straight down. It goes down and back. So what are you also gaining? You’re gaining a little bit over jet, right? So if I’m adding three millimeters of length and I don’t want to deepen the overbite, maybe I’ll open them up three millimeters.

Sometimes that can create a natural contours though. Okay. Because you’re having to add a lot of material. So sometimes you can just open them up by two millimeters. Now you’ll say, okay, well you just said don’t deepen overbite. Yes, true. But I’ve also increased the overjet. So now that leads to a shallower angle of guidance. So even though the overbite might be slightly deeper, the angle of the guidance might be slightly shallower. So it might still happen.

[Jaz]
But how did you gain more overjet? Sorry, but did you increase the vertical dimension or not in that example?

[Mahmoud]
Yeah. Opening the vertical dimension, you will decrease overbite and you will increase overjet. Leading to an overall reduction in the angle of the guidance, right?

[Jaz]
And this is important because the kind of cases that we’re seeing where we have got excessive anterior wear, where we need to think about aesthetics and raising the vertical dimension are the cases whereby one of the etiological reasons they ended up in that scenario is because they had a lack of overjet.

[Mahmoud]
True. And a lot of anterior tooth wear cases end up becoming more class three, right? Patients become more and more edge to edge and you have no room to restore. Opening the vertical can actually allow you to gain a little bit of overjet in those cases.

[Jaz]
Make them more class one or tending towards class two. But I just wanted to highlight something important you said. When we have that sometimes tricky scenario whereby we’re thinking, hmm, can I manage this wear case purely restoratively? Or, should we bring in ortho? I just want to highlight a wonderful thing you said, okay? Like, which teeth need treatment? So, what really helps in my planning is I have the occlusal photograph of the patient.

So, the upper occlusal photograph and the lower occlusal photograph. And then I will give it a traffic light system. Something I saw Basil Mizrahi do years ago, maybe 9, 10 years ago. And you put like a green light for this tooth just does not need any work. It’s a beautiful tooth, okay? Don’t touch it, okay?

Unless you, there’s no reason to, there’s no need for treatment here. Amber means that, okay, maybe it’s got like an MO amalgam, right? It’s not what carries issues, but it won’t be the end of the world if you restart the clock and actually treat that tooth. Red means this tooth absolutely needs treatment, okay?

And so if you’ve got lots of red and ambers, then maybe, and as long as the teeth are generally well aligned, then maybe this is a case for purely restorative management. If, however, you’ve got lots of greens and a few localised areas of red and ambers, then perhaps orthodontics can help you to improve those teeth, instead of having to restore a whole bunch of teeth that are green, that don’t need much restorative. Is this a technique that you use as well?

[Mahmoud]
Yeah, I mean, I don’t use the lights necessarily. I learned this from, I think, is it Spear that uses A, B and C teeth? Something like that.

[Jaz]
Ah, I think you talked about this before, yeah. Tell us about A, B and C teeth.

[Mahmoud]
It’s almost exactly the same. It’s like, I can’t remember which way it goes, but like, A teeth would be, look, these need treatment yesterday. B teeth are-

[Jaz]
Or maybe A is like, this is A plus tooth, this is a good tooth. Or maybe it’s the other way around, who knows? But the concept is the same, right? You’ve identified which teeth need treatment, which teeth don’t need treatment, and that is a useful exercise to do when you’re thinking, hmm, will we benefit from orthodontics or not?

The other thing is though, if the patient’s got just like crowding issues as well as restorative issues. It’s just so nice for your occlusal planning to relieve the crowding and get everything lined up and those slightly over rupted teeth to be in line, just getting everything in line as a huge benefit and it helps us to gain the vertical dimension as well sometimes to restore that case. So Ortho I’m a big fan.

[Mahmoud]
One thing I do harp on about, but maybe too much is the inclination of the upper incisor. Okay. What I found at least is it’s actually very difficult to get a good sort of amount of overjet or freedom in the envelope on teeth that are retroclined purely restoratively.

It’s just the shape you’re going to create is going to tend towards creating a restricted envelope because of where the tooth structure is. So proclining those teeth usually, or giving them a normal inclination with ortho usually makes the restorative occlusal planning much, much simpler. So if a patient has really retroclined or very upright teeth, I will almost always push for ortho, even if everything else is relatively well aligned. I think it has a huge advantage over managing those cases purely restoratively.

[Jaz]
As we say, there’s a lack of chewing space in those scenarios. There’s too much teeth bashing together at the front, or figuratively speaking, if you think of it like that. And that helps us solve our restorative cases so much better.

So, so far we talked about how we were scared of raising the vertical dimension. Then we did it, and we realized our patients didn’t implode. We talked about DAHL as a gateway into doing bigger cases. We talked a little bit about the limits of raising OVD and really it’s case dependent, but five millimeters in the Abduo paper, and suggest that it’s very predictable.

You mentioned a great reference about the six millimeter splint and how we have the ability to adapt. We talked about which teeth need treatment, which teeth don’t need treatment when it comes to ortho versus purely restorative debate. Then the other thing that we should really discuss in vertical dimension is in fact, before we come onto this, I feel like there’s more to come from you in the sense of what you were answering that question of what do you look at, right?

So you already said, okay, which teeth need treatment, which don’t, but also you said overjet. What else are you looking at?

[Mahmoud]
All right, so we said the aesthetics we said essentially the anterior relationship and then it’s occlusal clearance or restorative-

[Jaz]
Space.

[Mahmoud]
Okay. So one of the most useful things about opening the vertical dimension is gaining space for your material without having to prep teeth that are usually already quite worn. Now that is a huge benefit for anterior teeth, but also can come into play on back teeth. And it’s probably one of the most common reasons you open the vertical dimension in relation to back teeth. It’s to gain restorative space, but you do have to be careful because as we already mentioned, for every millimeter you open at the back, You’re going to gain maybe two to three millimeters, depending on the geometry of the jaw at the front.

So, if a patient needs restoration of the anterior teeth already, then that might not be such a big issue. But, you do sometimes get patients, especially erosive wear patients, that have localized posterior tooth wear. And your initial reaction might be looking at them thinking, yeah, I’ll just open the vertical dimension, right?

But you’ve just got to be very aware of the fact that you’re going to gain a lot of space at the front. And if that patient has like a normal anterior relationship already, you’re going to end up creating a huge gap that you then have to fill with possibly restorations of very abnormal contour.

Another case where either surgical crown lengthening or orthodontics need to be on the table. So it’s very important not to just, as soon as you see where you think I’m going to open the vertical. No, think about where you want the teeth first. So make, as in our friend, Michael Melkers says, how’d you want it to look? You want them to look like teeth. How are you going to make it fit? Your options are going to be open the vertical ortho surgical crown lengthening and then take it from there.

[Jaz]
And how do you mitigate the forces on those teeth as the final step? Hat tip to our good friend, Mike. We spent a good few days with him and Lane Ochi recently.

[Mahmoud]
Speaking of hats, has he taken any videos with the hat we gave him on?

[Jaz]
We sent him a nice little Yorkshire based hat, when we saw him in Chicago for AES, so I think he might have sent me a photo, it’s in my private stash, I’ll send it to you sometime. Right, so the elephant in the room now, Mahmoud, is joint position, right?

Because I have worked with mentors and principals before who said, listen, Jaz, it’s, we’re overcomplicating it, right? Just open the bite. Give the patient enough contacts and the patient will find their own bite. You don’t need to worry about this old centriculation nonsense and deprogramming and don’t waste your time with these lucia jigs.

Whereas there’s other mentors that we have which are, we must find, to the pinpoint precision, the centric relation or the patient will have a heart attack kind of thing, right? So, firstly tell us, when we’re opening the vertical dimension, why do we even need to think about joint position? Where does this come in?

[Mahmoud]
Okay, so essentially when you’re opening the vertical dimension, you’re going to establish a new MIP position that is slightly open from where the patient is now and ideally what’s happening is that the jaw is rotating open okay, the reason joint position becomes important is if that point of rotation is stable and repeatable then I can take the records on the patient, I can move them to the articulator, whether that be virtual or analogue.

I can design the new vertical dimension, the new restorations or whatever. And then I can take it back to the patient and the anticipation is that it’s going to be fairly accurate. Especially if you take that bite registration. at the vertical you want the restorations made at. Okay, I think both of us harp on about this for quite a lot. Now, if that joint position is not repeatable

[Jaz]
So can we just spend a minute, just talk about that, because before we continue, because I think that’s so, so important, right? That’s a real takeaway from this podcast is, let’s say that hypothetical scenario, we’ve decided that we’re going to increase the vertical dimension here by five millimeters because that’s how we want to lengthen the teeth by about four millimeters or six millimeters whatever. And we’ve decided that we’re going to raise the vertical dimension by five millimeters because in this patient, it’s going to allow us to restore the aesthetics. It’s going to allow us to get more overjet and a better overbite overjet relationship and lots of the back teeth need work. And so we’re kind of doing a full mouth rehab here.

But what we don’t want to do so just like we said in the last podcast something we must understand what it isn’t right and the opposite of it. So if in that scenario that patient who needs five millimeters opening, okay we instead send the technician a centric relation bite record, okay, with three millimeters opening, just because we said, okay, I’ll let the technician open up the bite to where we want to be, okay, and then we can wax it up, that is very error prone.

Because the articulator is not the TMJ, it’s not the jaw, it’s not the patient, and so when they open up the articulator, that’s creating an error, whereas if we just send the technician the scan, or the stonebite records, the PVS records, wherever you want basically, with the exact vertical dimension that you want the patient to be, you’ve now eliminated the error of opening the articulator.

And this has helped us both, and a lot of people, and what we find in the occlusal camps is actually this is a very verified technique, to send the technician the desired vertical dimension exactly. Don’t allow this error to be introduced in opening the articulator.

[Mahmoud]
What will happen then is you’ll get your MIP, your new MIP contacts will probably be very accurate.

[Jaz]
Extremely accurate.

[Mahmoud]
Getting the jaw to move or getting the articulator to move, there’s still error there. It’s not like it’s-

[Jaz]
And I just want to remember this case, like the first time I did this years ago, a young grad, and I did this, and I was just amazed. It was a DAHL case, again, venturing into tooth wear cases, opening vertical dimension, it was a DAHL case, and I got the patient to bite together, and I saw these six dots. I was like, what? Like, this is amazing. You use one dot, you grind it down, then you get two, then you get four, then you get two again, and then you get six. That was amazing. That was like, holy moly. Why didn’t they emphasize this enough in dental school kind of thing?

[Mahmoud]
Yeah. It’s secret weapon, right?

[Jaz]
But it doesn’t take secrets out. So everyone knows it.

[Mahmoud]
Yeah. But you then need to develop the ability to figure out how much room you need. So one rule of thumb, we already mentioned, maybe open the bite about as much as you’re going to add length. Second one is if you’re restoring back teeth, right? Consider what material you’re going to use and speak to your technician, right? Send them some pre op records. They’ll tell you I need to restore the upper and lower, I need four millimeters, right? You’re going to have to open at the back four millimeters. You know how much you need at the front, that sort of thing.

[Jaz]
And one thing we haven’t mentioned yet, it’s just important. The caveat dimension is, are patients that haven’t had any issues from raising the vertical dimension. That’s kind of because in our assessment of that patient, we check for joint health, we check for muscle health, and we excluded those patients that are not suitable because either they have active temporomandibular disorders, or muscle pain.

They have a joint position that’s not reproducible. So all those things that we talk about in Occlusion Basics And Beyond, live course, online course, that kind of stuff, we have ensured that. And that’s how I got into managing TMDs. Because as part of the Occlusion 101, Lesson 1 is, make sure the joint’s healthy.

And I started to learn about the healthy joint. And then I started to help my patients with not so healthy joints. And now it’s amazing which way that your career and interest take you, but it’s all starting in that initial assessment. Which is another now point to discuss is the use of occlusal appliances prior to raising vertical dimension.

Lots of my colleagues trained at the Eastman that this is standard protocol. Give everyone a stabilization splint, test the vertical dimension before committing to it to make sure there’s no issues. And I find that, that’s perhaps not necessary with some other occlusal appliances available because it is predictable.

But when you have that patient and you’re in doubt, what a wonderful thing if you’re in doubt for that patient because they’ve failed your assessment. They had this dodgy joint, for example, for want of a better word. For that patient to test with an occlusal vertical dimension appliance is a great thing to do because you’re not doing anything damaging or reversible.

[Mahmoud]
Yeah. Again, I think we do this a lot as dentists and we tend to use maybe sometimes the wrong words or hyperfix it on semantics. Yeah. So, you’ll see a lot of people say, oh, I want to test the vertical dimension with a splint, right? The patient has no joint pain, stable TMJ, stable muscles.

Fine. I want to test the occlusion on a splint. What you’re testing is probably the stability of that patient’s joint in terms of, I can give them the splint, I can perfect the occlusion on it, and then I’ll see them again in three months and the occlusion’s the same. What you’re not testing is whether the canine guidance or whether this angle of disclusion or whatever is going to work for the patient.

You’re not testing the vertical dimension or the occlusal scheme as such, because you can do things in a splint that you cannot do on real teeth, or it’s very difficult to do on real teeth, or the consequences will be difficult, right? You can get away with a lot more on splint than you can on the edges of your ceramics or your composites.

Using splints is a great way of testing the stability of someone’s stomatognathic system and knowing that their occlusion isn’t going to change on you and they’re not going to develop pain or discomfort from what you do.

Interjection:
Does occlusion confuse you? Do you feel like you need it taught in a way that actually makes sense? Whilst we have got a great online course, we totally understand that some people learn better from in person and hands on programs. Our Basics of Occlusion face to face course will be two enlightening and fulfilling days with nine hands on activities. We cover crowns on dodgy occlusions. No other course in the world covers this and it’s so important because you know what?

None of my patients have a perfect occlusion. We often have to work to a non ideal occlusion, but we want everything to work for the longest time possible. We will teach you occlusal assessment, occlusal diagnosis, and occlusal planning to make sure your crowns last, your patients are comfortable, your bonding doesn’t chip, and you can go to sleep at night not worrying about restorative failure because our occlusion course is all about improving the predictability and longevity of our work.

The next date is 11th and 12th of October, 2024 in Surrey, UK. And you can book this now via www.protrusive.co.uk/boo. That’s BOO, Basics Of Occlusion.

[Jaz]
And I very much echo what Lane Ochi with over 40 years of experience working Beverly Hills taught us recently at the course and reminded us is that he will not treat a wear case or he’ll seldom treat these big cases without the patient first wearing an occlusal appliance. Now, not necessarily in the old school way of testing the OVD for six months with an ugly appliance to make sure the patient doesn’t implode. It’s more, can I trust this patient?

Is the patient understanding what I’m saying? Are they taking some ownership of their own part in the destruction of their teeth in those high force patients? Relaxing the muscles, okay? And just seeing, okay, is this patient someone you want to take on for comprehensive dentistry ? And then when they come back, could be as soon as four weeks, could be six weeks, could be two weeks, okay?

Everyone’s different, could be many months. And there’s a whole thing we can discuss here. But, I am very much the same, is that if I have a high force, destructive patient, I don’t want them to be a patient of mine unless they’re going to commit to wearing an appliance afterwards. And the only way you’ll know they’re wearing an appliance afterwards is they’re willing to wear an appliance and wear it well beforehand.

[Mahmoud]
Absolutely. And it gives you a chance to get to know them, know what they’re like, know that you want to work with them because these cases can go on for a long time. They can be stressful. And in a way, the more teeth you do on a patient, the higher your risk. It’s just the way it is. It’s just a game of numbers, right?

So I said this to a patient earlier this week actually, where I can treat more of your teeth and it will give you more control. It gives me more control of what’s going on. Yeah, and I need that to manage your bite and stuff. But at the same time it means I’ve treated more teeth, right? There’s more of my work in there.

So just the probability, the pure probability of you having something chip or break goes up. And I’ll usually say, having one or two things go wrong every one or two years that we need to fix might well be the case. Are you okay with that? To date, that has not been my experience. It’s far less than that. But I want the patient to go in prepared. Okay, because if that does happen, and they start having a hissy fit, then you’re going to be in for a hard time. That was my intention.

[Jaz]
It’s about identifying those high risk red flag patients and make sure they’re managed well. And you have that kind of conversation that, okay, you’ve destroyed your God given or evolutionary driven enamel and dentine.

Enamel being the hardest thing in the body. You’re going to do the same to my restoration, so A, you’ve got to pay every time you do it. But also, let’s protect us by having this occlusal appliance. For those patients who attrition is a big etiological factor, for those patients whose attrition is not a big factor, it’s more erosion, then that’s a lower risk patient, it’s a different kind of patient.

But just to give a flavour of what we’re thinking, what Lane Ochi meant when he said that at the lecture. So, back again to joint relationship, okay? What’s the disadvantage of potentially just, opening the patient up on articulator willy nilly without worrying about where the condyle is.

[Mahmoud]
Okay. So yes, we have a lot of people doing that and saying that. Now that on its own should tell us that, okay, it, it kind of works. I can explain to you why it works, right? Why it can work. Most people who do have a shift between their centric relation position and their MIP position in terms of the condyle that changes within sort of an eighth to a millimetre. So one eighth of millimetre.

That’s it. Okay. So the condyle doesn’t move a lot. Now imagine you got this patient, they’re in MIP. While the teeth are still in MIP, you’re just going to take them on your articulator, you’re just going to open things up, and you’re going to fill the space with restorative material, and you’re just going to do a DAHL treatment on this patient three to three in composite.

Now, what’s going to happen when the patient is only contacting on their front teeth? Generally speaking, the condyle is going to seat, right, to an extent. And then one of two things is going to happen.

[Jaz]
What does that mean? Because I’m thinking for our younger colleagues, they may not know what that means.

[Mahmoud]
Okay, so you’ve essentially now created a tripod, which is basically the same thing as a deprogrammer. You’ve put a fixed deprogrammer in their mouth and the lateral pterygoid will relax and the contraction of the elevator muscles will take the condyle from being somewhere on the eminence up into the fossa, okay? Into its more-

[Jaz]
Stable position. Or the ball has now sat into the cup, in the socket. So the ball goes into the socket nicely in a snug position, aka centric relation. So that’s what we mean by when we say the condyles have seated. They’ve gone into their stable position. It’s like when you put an egg into a cup, it falls into one position. It’s a bit like that with a joint. It’s a simplification model, but we get the idea.

[Mahmoud]
Yeah. And obviously, you know me, like I like to overthink things and do these sort of mind experiments. Now, does the condyle always seat all the way? No, if you have overerupted posterior teeth or a really steep curve of spee, right?

One of the back teeth might hit first before the condyle is fully seated, okay? And then that may become the patient’s new learned MIP, right? Because that’s how most of us work. If our condyles are seated and we close, we hit one tooth or two teeth and our lateral pterygoid is programmed to bring the jaw forward until we hit more teeth, right?

So that may well become their new MIP position. They’ve developed a new interference to closure, the lateral pterygoid has become programmed to create a new MIP somewhere, right? And it happens to hit your composites and maybe one or two other back teeth and then things may be settle. Okay. That may be one way that things work when you open in MIP, the other way it might work is in fact the condyle does fully seat and it just so happens that your composites, your DAHL composites are big enough that even though the mandible has moved back a little bit, it hasn’t moved back far enough to fall off of your composites.

[Jaz]
But now instead of all six teeth hitting, you might just have a couple of teeth hitting. You should just DAHL that in to get even contacts everywhere.

[Mahmoud]
Exactly. Right. That’s why you’re reviewing the patient and that’s fine. The problem is, and I had one case that really scared me, right? No, I didn’t treat the patient, but I was doing my normal sort of occlusal assessment. This kid. He was a kid, he was like 4, he had like a five millimeter shift between his MIP and his seated condyle position. Yeah. I had to use my entire wad of the leaf gauge almost. It’s even more than five millimeters.

It’s a huge shift. Right? So imagine now you take someone like that and you just open them up on your DAHL composites in MIP and they get deprogrammed and all of a sudden they’re condyle seat fully. So they’re probably only going to have ARBs, massive AOB, you’ve just treated the patient, they’ve lost their MIPs, maybe you can get it back, maybe not.

And now you’re stuck. This patient probably needs ortho, maybe even more complicated. So it’s more predictable to design your OVD increase from a seated condylar position. However, for the majority of patients that have a small shift, the consequences of not doing it may or may not be. problematic, but it’s just so easy to screen at the very least, right?

Use a leaf gauge, screen the patient, find out how big is their shift. And if it isn’t massive and you want to do it in MIP and adjust it, fine. For me, if I’m doing that, I might as well take the central relation bite at my desired OVD, like we just said, have the wax fill in the space. Design my restorations and then know that on the day that I do the composites, at least my new MIP contacts at the open vertical dimension are going to be so close to ideal.

My adjustment time is going to be minimal. And I know that the condyle isn’t going to seat anymore, or at least not much more. Okay, let’s not pretend we’re machines, but it won’t be much. So yes, I will still bring them back in for review in a week, two weeks, six weeks, whatever it is. But the adjustments are still going to be minimal and you’re asking the patient to adapt as little as possible which is always going to mean fewer issues.

[Jaz]
I think that the key word we haven’t mentioned yet I’m sorry if I missed it. We’ve said it is reproducibility, right? So the ability to reproduce the bite, so for example, the patient bites get and sometimes the patient’s muscles get tired when they’re opening closing and then if you’ve done a major change that sometimes they bite together and don’t quite know where to bite together. But if you can just guide them either through a leaf gauge or gently by hand into their near enough their stable condyle position or CT position, centric relation.

Then you can kind of guide them, and it’s reproducible for us. It’s reproducible for us, reproducible for the patient. So if you ever lose control of the case, this is what I aim for on the articulator in my wax up, and this is what we’re going for. And that’s when the ball is in the socket.

And so, reproducibility is great. I agree that it’s not a magic position. And even Manfredini and other authors call this a utility position. It’s very useful for restorative dentists to allow us to plan our dentistry around this position of the condyle. So, most schools of thought, most schools of occlusion would condone, if you’re raised in the vertical dimension, do so, do all your planning in the centrifugal or stable position.

Other schools include neuromuscular, whereby they’re finding the rested length of a muscle, and you’re going with that. And you know what? That works as well, okay? So if you want to use that method, that’s good. I think the ability to get an even bite left and right, and patient comfort, and as long as the patient can find the same position over and over again, is probably more important than which method you use.

But certainly in the major occlusion schools, using central relation is accepted, and when we’re raising the vertical dimension, we may wish to use it rather than what we call arbitrary, rather than just opening up willy nilly. Two downsides of using central relation is, A, that patient, like you said, has got a huge shift, okay?

A, you’re making them more class two, okay? So, aesthetics, and also, what are you doing to their airway? So we may choose to, in that patient, use an arbitrary position and hope for the best and try and make sure we’ve got nice coupling of the teeth on the wax so that the teeth can kind of find their own position.

There’s only one place the teeth fit together, basically. But that’s a whistle stop tour of vertical dimension. I’m just going to check my questions again, Mahmoud. But, Mahmoud, any other reflections? So we covered about the limits of raising vertical dimension. And we talked about whether it needs to be in centric relation or not, and I would say that yes, ideally it should, but you can get away without.

It’s just an element of risk involved, how much risk you want to take. In some patients, the risk is calculated, and you may get away with it. In other patients, you may wish to program that in, and I mean, you certainly tend to plan to CR. Any other points of assessing or increasing the vertical dimension?

[Mahmoud]
I’ll just quickly sort of summarize a couple of things, but also add the note about relapse, right, because that comes up a lot. But we’ve all, Jaz went through the article that says increasing the vertical dimension up to about 5mm is fine in the anterior, but you do need to make sure that the patient has healthy, or at least stable, TMJs beforehand.

Otherwise they do not pass go. And, you know, Jaz has a wonderful, wonderful bit in OBAB teaching how to red light, green light the joints. There is currently no evidence that it’s bad for the TMJs to open up the vertical dimension as long as it’s healthy beforehand, right? And there’s no evidence that it’s bad for the muscles either.

I mentioned the Helsing paper and the adaptability of the muscles. Now, and this relates to what I’m going to talk about next, which is relapse. And if you think about it, what’s happening to the muscles when we open someone’s vertical dimension? You’re essentially stretching the elevator muscles, right? The medial pterygoid and the masseter muscles. You’re stretching them.

[Jaz]
And more stretched than they were before. Because sometimes it’s not really stretching. It’s sometimes restoring the length. Because if someone’s bunched up and overclosed, and the muscles like scrunched together, you’re actually making them the right length. It’s like going from a fist to an open palm, rather than stretching it per se. But yes, the concept is the same.

[Mahmoud]
Correct. Let’s assume a patient has a vertical dimension that is working for them. And you now then forcibly open that vertical dimension, you’re going to be increasing the muscle length. Okay?

[Jaz]
Yes.

[Mahmoud]
And that is why people say that any increase in vertical dimension will relapse, right? Because the muscles want to maintain their contracted length. So, essentially, they close the vertical dimension back in. And it’s not like they jam the teeth back into their sockets. But you get the whole alveolar complex moved.

And it’s been shown that that happens over a period of three to four months. Okay. And it actually just generally goes unnoticed by the dentist and by the patient. Bite force actually changes when you open the vertical dimension up to a certain point. So if you open someone by about five millimeters, you’re actually going to increase the maximum bite force they can generate.

But again, that goes back to normal ish in about three to four months. And also anyone who’s watched our canine guidance versus group function lecture on OBAB will know that if you take someone who’s got group function and then you give them canine guidance, yes, their muscle activity might actually go down for a period of time, but after about three to four months, things again because of the adaptability of the system will go back to normal.

So it’s all of these things that, at least for me, inform my philosophy of how long do I leave someone in provisional when I’m opening the vertical dimension. The number of three to four months keeps coming up, depending on how risky the case is. That’s about how long I will leave them in provisionals for, because I’ll know that most things I’ve changed have normalized. And if by that point they haven’t broken anything, nothing’s come loose, then I’ve got a good ish idea that I’ve created a scheme that at least works.

[Jaz]
So in the highest X cases, higher risk patients, not only are we utilizing a technique of a occlusal appliance in the pre planning phase, relaxing their muscles and testing compliance, but thinking about provisionals for a longer time as well, which also tests the vertical dimension increase, which we said at the very beginning, in once the patients have got healthy joints, you’ve established that it’s okay to proceed.

We shouldn’t be as scared as we used to be because it actually is tolerated really well. It’s very predictable. It’s great to increase the vertical dimension in the appropriate cases. It’s when we have more fun, we get to do more units, do aesthetic dentistry, apply it, treat wear cases. So thanks for that whistle-stop tour.

Like, we could go on and on about vertical dimension. There are whole continuums and days dedicated to vertical dimension. But if anyone’s got any questions, please do comment below. But Mahmoud, thanks so much for joining me again on this. So next time in the series, we’re covering how to, and this is a nice clinical topic and really real world applicable, how to minimize adjustments.

We don’t like doing beautiful restorations and hacking them and grinding them away. So we’ve got a episode on direct restorations, how to minimize adjustments, and also indirect restorations, how to make sure what we get back from the lab means that we’re doing the least amount of adjustments possible. So we split it into indirect and direct. So I’ll catch you in those episodes Mahmoud to share more occlusion goodness. Thanks so much.

[Mahmoud]
Catch you then.

Jaz’s Outro:
There we have it guys. Thank you so much for listening all the way to the end. Thanks as ever to Dr. Mahmoud Ibrahim, who you should check out on Instagram. I put a link to his profile in the show notes. This episode is eligible for CPD. Protrusive education is a PACE approved provider. And all our quizzes, when you submit them, has a little box for your AGD membership where it’s relevant. Our CPD Queen Mari is going to email you a certificate every time you complete an episode and so throughout the year you can easily rack up 40 to 50 hours. So the value for money for a Protrusive Membership is absolutely phenomenal, I’m sure you agree.

So if you’re not already on it, go to protrusive.co.uk/ultimate. That gives you access to all areas. All our masterclasses and every month we add new content. You can use the app on the App Store or the app on the Play Store or the good old fashioned laptop on the website protrusive. app.

I hope you’re enjoying Occlusion Month so far. If you’ve got any recommendations for topics, we always like them. Please do put them in the chat wherever you’re watching this. And if you are jogging or chopping onions, thank you for doing those things as you listen to Protrusive.

I want to thank Team Protrusive whom without this would not be possible. And all the premium members of the app who are on a paid plan because you are the ones subsidizing this podcast and allow us to go episode after episode and spend the time to create this content with the PDF transcript, the premium notes, infographics, and the bespoke videos that we make. Thank you so much once again.

I’ll catch you same time, same place next week. Bye for now.