Occlusion for Complete Dentures – PDP162

[Jaz]
The man behind Impression Club, of course. So just a little hat tip to Rupert for recommending Dr. Andreas, because according to Rupert, Andreas taught him everything he knows.

And I was blown away by the knowledge, but also some of the gems that he gave that are really going to save us time. Like, I was really debating what to title this episode because it had so much breadth and actually when I was recording with him, I was supposed to, by the script, asking so many more questions about different types of dentures and partial dentures and overlay dentures.

But we just had such a great time geeking out on complete dentures that the whole focus of this episode came about complete dentures, but in a way that no matter which experience level you’re at, you’re going to take something away. For example, we discuss everything from checking the border extensions to the vertical dimension to discussing the base materials that are available.

And simple things like ensuring a comfortable fit at the day of delivery. The biggest takeaway for me, as someone who’s really into occlusion, is the Protrusive Dental Pearl for today.

So, hello Protruserati, I’m Jaz Gulati, in every episode I’ll give you a Protrusive Dental Pearl, and today’s pearl is from the main episode. And it’s kind of surprising, like, I spend a lot of time when I’m doing complete dentures, which nowadays is not as many as I used to, just because the population that you treat and the different demographics, etc. So I used to spend a bit of time with balanced articulation, making sure I follow the BULL rule, adjust the buccal of the uppers and lingual of the lowers to get a lingualized occlusion and occluding scheme.

Protrusive Dental Pearl
But the pearl I have for you is that actually, Andreas just goes for a group function occlusion on his dentures, and you’ll see why he does that. If you’re spending too much time on the occlusion side, then maybe you are wasting your time. And there are other aspects of complete dentures where we should be focusing our time to get better outcomes for our patients.

Oh, and just as Andreas says later in this episode, enter bolus, exit balance. Because ultimately when there is a bolus between the complete denture set, then all those dots and lines you work on are kind of irrelevant. Just some latest updates before we join the main episode with Andreas that recently I delivered a webinar called Quick and Slick Rubber Dam.

I shared so many videos of different scenarios of finding a a predictable framework of applying rubber dam like quadrant isolation in a fairly efficient time. That’s now been uploaded to the premium clinical section and in the chat, [name] Dr. [name] from Ghana, Africa, he asked to see all those little mini videos I had of different cases and different examples of rubber dam isolation.

He wanted them to be uploaded to the premium section. So I said, what the hell? Let’s do it. So I’ve decided to create like a little case bank. So there’s a story behind this is one of the best extraction course I ever did was with Dr. Nekky Jamal. He has a fantastic online course on wisdom teeth extraction, which I’ll link to below and you can get 15 percent off that using the code protrusive.

And so what I love about his course is that when I need to extract a wisdom tooth, I will look at my radiograph. I’ll see what I’m up against. Mesioangular, distoangular, whatever. And I’ll pretty much find a similar case. on his course, like a case bank he’s got so I can watch that video before I see my patient just to get some ideas and inspiration.

And it’s good to see the techniques that he applies. So in a similar fashion, I’m going to upload lots of different rubber dam scenarios to the protrusive app, which of course you can access on your laptop via www.protrusive.app or iOS Android. And you’ll have different scenarios like. When the coronoid process is in the way and you can’t get a clamp on, what do you do?

Or what if your floss and rubber dam keep is tearing? Which dam to use, which not to use? You’ll get all those in the case bank. And of course, if you want to watch the full one hour webinar, which is eligible for one hour CE credit or one hour of CPD, then you can head over to the app as well to get that. So I hope you enjoy that rubber dam goodness. Let’s now join Dr. Andreas.

Main Episode:
Andreas Artopoulos, welcome to the Protrusive Dental Podcast, my friend. How are you?

[Andreas]
Thank you. I’m fine. Thank you. How are you?

[Jaz]
Yes, great. It’s so nice to speak to you about a big topic, which I love occlusion, but specifically applied to removable prosthetics.

Let’s not get into implants. Let’s just go to complete dentures, partial dentures and that kind of stuff. At least that gives us a little bit more of a niche and to talk more focused about it. Before we delve deeper into that, tell us about yourself. I see you’ve got the form labs behind you. You’re in a lab. Tell us about you and your work.

[Andreas]
How far back do you want to go? I mean, I’m a bit older.

[Jaz]
I see as you can make it.

[Andreas]
Okay. I was born and raised in Thessaloniki in Greece, where I studied dentistry. I graduated in 2006 and then immediately within a couple of months, I moved to London, UK. I practiced there in a general practice for a couple of years before I enrolled my first a master’s course in a removable prosthodontics at King’s College, London.

And when I finished that, I loved it so much that I decided to stick around and do a second master’s. So, I did a second master’s in maxillofacial and craniofacial technology. I don’t know if you know what that is, because a lot of people don’t.

[Jaz]
Is it like, I don’t want, I don’t mean to just simplify it to one appliance, but like obturators and replacement prosthetics?

[Andreas]
Yes, it’s-

[Jaz]
Often mouth cancer and stuff?

[Andreas]
It’s all of that and a little bit more, so we’re dealing with facial prosthetics. It’s mostly for oncology cases, but also trauma cases and congenital defects. So we can do any kind of extraoral or intraoral prosthesis, like an eye, an ear, a nose, a finger, obturator.

[Jaz]
That must be so rewarding. I mean, we do teeth and we get a huge buzz out of it, right? But when you do someone’s eyes as well, the nose, that must be the nicest feeling.

[Andreas]
It’s fantastic. I love it. I wish there was more cases to do because it’s very niche market, obviously. And even more so in a country like Cyprus where I’m based now, I would not have that many cases, but it’s the one thing I love most, but I was lucky enough because in my department at King’s, the whole department was heavily focused on digital technologies beyond the conventional prosthetics.

So anything to do with 3D scanning and 3D printing and 3D planning of surgeries. So I got heavily invested in that as well. And after I finished my second master’s, I stayed around at King’s for a few more years. And I took on various teaching and research posts until Between 2012 and 2016, my research was mostly focused on digital technologies, anything to do with face scanners, 3D printing, and later on augmented reality devices like Google Glass, try to develop some clinical applications for augmented reality.

And then, I moved to Cyprus, where we set up a private practice and laboratory with my wife. We specialize in removable pros, implant prosthetics, maxillofacial prosthetics, and my wife does [unclear] implants. And after a couple of years, I also, I was lucky enough, together with my online guy Dimitris Neofytou, to set up the first service in Cyprus for 3D planning and 3D printing.

So we’re doing lots of implant planning cases, orthognathic surgery planning, and some oncology cases. And since 2019, I started teaching at a local university, European University Cyprus in Nicosia. And I am course coordinator for removal prosthodontics. As I told you earlier, I have a five-and-a-half-year-old twin. So it’s quite a busy schedule.

[Jaz]
It’s a busy time. You’re doing all these amazing things in the lab, but more power to you. That sounds absolutely brilliant.

[Andreas]
And what else, I love video games. That’s-

[Jaz]
Really?

[Andreas]
Perhaps.

[Jaz]
What do you play? What did you play yesterday? What did you play this last week? What have you been playing?

[Andreas]
I play everything from Atari 2600 from PS5. I mean, you can see my headset is the PS5 headset. I hardly have the time to play as much as I would like to, but I like to play a little bit at night after everyone’s asleep. And just to wind down and after all the work, and before I go to bed, so…

[Jaz]
Did you get your kids into gaming yet? Like, they’re five and a half, and I’m always thinking, nowadays, they’re saying, screen time is bad. And I’m thinking there’ll come a point where my son’s going to ask for some video games, and what do we do? Like, you love video games, my childhood was a big part, I don’t do much now, but as a childhood I did. What’s your stance on your kids playing video games?

[Andreas]
I think I would love them to get involved, because I strongly feel that video games nowadays can offer a lot more than spending time on television, for example. I try to get them started with an old Atari game and Nintendo NES, because they’re simpler games, easier to grasp.

They seem to like it, but they’ve not been asking for it, so I don’t want to push them into it, I’m just waiting for the right time. But somehow, we managed, with my wife, to keep them away from tablets and smartphones and things like that. So, they will watch TV, but they might go for a month without asking it, so if they don’t ask we will not turn it on.

And it’s always regulated without wanting to spend too much time in front of a screen. But trying not to be too strict about it as well. And obviously you have to regulate the content. That’s the most important thing. So I’m not saying tablets are bad, but you have to spend the time to regulate what content they’re into.

[Jaz]
Very true. Especially at that impressionable age. Let’s now talk about a big part of what you do. Removable Aesthetics, and particularly occlusion. And there’s so many different places that we can explore. So let’s start with, and I’ll kind of guide you where we can serve the Protruserati the best.

Complete dentures. Let’s say the complete dentures have come back. Let’s skip the wax jaw restoration stage for a moment. We’ll come back to it later. Let’s say the complete dentures have arrived fresh. Okay. They’re ready to go inside. A dentures patient now bites together with their complete dentures.

What should the occlusion look like with respect to class 1, class 2, class 3? Because there is a thing I’ve seen in the past where dentists, they try to make all complete dentures class 1. And I have been taught that perhaps we shouldn’t be doing this. What is your stance on this? And how can we help the dentist figure out? Okay, what incisal classification should I make my complete dentures?

[Andreas]
This is a very interesting topic you chose to get started. First of all, to answer the first part of your question when the dentures are processed and finished and you’re going to place them in the mouth for the first time.

If you haven’t already done so when using permanent bases for your jaw registration, if it’s the first time that you’re going to fit those bases in the patient’s mouth. The first thing you need to do is to ensure that they’re comfortable. So you place each denture individually by itself in the patient’s mouth and you press down towards the tissues in the second premolar to first molar region where the mastication occurs, and make sure that they’re comfortable for the patient.

Before you even do that, you can visually assess and you can manually check the fitting surface to make sure there are no spicules of acrylic or anything that feels sharp. If there’s anything at all on the fitting surface that feels sharp on your finger, It means that it will feel painful in the patient’s mouth a hundred times over because the mucosa is much more sensitive than our fingertips. So first we need to ensure that the fitting surfaces are nice and smooth, and then we can place them-

[Jaz]
And can I say in case someone was multitasking and they didn’t like and they missed that bit. That’s something I only learned a few years at dental school. It was Lyndon Cabo t who showed me this.

And I pressed the denture down and the patient goes, ow. And I was like, hmm, I wonder what’s that? Where’s that happening? And he came over and he just ran his glove finger. Ah, I found it. There’s a spike here. And to me, I thought, okay, maybe the technician would sort this out, but there’s got, they are doing a hundred things and that little tiny spicule sometimes gets missed.

But like you said, we visually inspect and with your finger and I almost felt like I wasn’t, I almost felt like I wasn’t allowed to adjust that part, but it just makes sense. Obviously that you get rid of that sharp bit that’s digging into them because it just makes so much common sense, obviously.

[Andreas]
Yes. And you can even you can get a square gauze and just run the gauze gently over the surface and see if it catches somewhere. This is also another-

[Jaz]
Very good. I haven’t done that one before.

[Andreas]
To identify any sharp edges. To be honest with you, I strictly instruct my dental technicians not to touch the fitting surface. I don’t want them to do any adjustments. I prefer to do any adjustments on the fitting surface myself. So that’s one thing. So maybe it’s not that the lab didn’t bother doing it. Maybe they agree with me that they shouldn’t be doing it. It’s something that has to be done clinically. And obviously, the next thing to do is use some pressure indicating paste to ensure that the fit is correct and that you have even pressure and you don’t have any pressure points.

[Jaz]
Which brand do you like?

[Andreas]
[Mizzy], I think, is the brand. It’s the standard pressure indicating paste. Now, the thing is that it’s getting a bit trickier to get hold of it, at least in some countries. I’m sure you can find it because it’s in UK, but we’re having trouble getting it for the university here. So here’s another clinical tip.

What you can use instead is the catalyst from the Zinc Oxide and Regional Impression Paste. It will behave in a very similar way. Of course, you can use a light bodied silicone or something like that, but it’s much more expensive and it takes much longer to set. So, with any of those, it’s not so easy to remove it afterwards.

So, you have to be careful if you use either the catalyst from the Zinc Oxide Regional Paste or the Pressure Indicating Paste. The Pressure Indicator Paste, the kit comes with a solvent that helps to remove it, so that’s handy.

[Jaz]
I’ll tell you what I use, Andreas. I use PSI by Coltene, Pressure Spot Indicator Paste by Coltene. Is that a good thing? Do you like that?

[Andreas]
Yes, I mean, it’s not the material that will make a huge difference, so long as it’s something that’s quite viscous and it’s easy to remove and you can have it in a thin cross section, it’s not going to make a difference. It behaves in a similar manner. So it’s not like there’s a right or wrong material to use, but obviously it has a lot to do with the cost and how easy and quick it is to apply and how quick and easy it is to remove afterwards.

[Jaz]
I mean, it’s so easy to peel away. That’s what I love about it.

[Andreas]
Yes.

[Jaz]
But it probably costs a lot more than the Mizzy stuff.

[Andreas]
It does. Yes. So, we check and we’ll make sure that there is a comfortable fit on the fitting surface. And then the next thing you need to do is, again, if you haven’t already done so by using permanent bases, you have to check all the peripheries. So you have to check the border extension, you have to check the border morphology. And again, applying some kind of pressure indicating media. And make sure that you’re not overextended, make sure that your borders are nice and rounded and smooth. And once you’re done with one denture, you remove it. And you place the other one and you repeat the whole process.

[Jaz]
Let’s talk about this, Andreas. Let’s talk about this micro step. So I’m going to keep interjecting because I feel like I want to extract so much from you. So complete dentures, as you know, is now a pretty much a postgraduate discipline, right?

We don’t get to do enough in our undergrad. So even these little things, which we think are simple, we need to explore this. So in terms of checking the border extensions, is it by pla-? Let’s say the upper one, you’ll place the upper, make sure it’s seated. And then do you hold the cheek and the mucosa and try and take the denture off and see if it’s overextended or do you keep it in place and just get the patient to do like exaggerated, like, ooh, and eeh movements? What is the best way to check that part of it, the extensions?

[Andreas]
Again, there is no right or wrong way. There’s many different techniques that you can employ to achieve the same goal. What I like to do is ensure my denture is fully seated and it’s comfortable and I gently hold it in place. I gently rest my finger, for example, in the center of the palate.

And I start pulling the patient’s lips and cheeks and see if I feel any movement. That’s one way to do it. Another way is obviously to let the patient do all the facial expressions, and that again will show you. And you can visually inspect for example, if you’re overextended in one particular area, by gently retracting the cheek, you can see the mucosa is being pushed up from the denture border, and you can see some blanching maybe, perhaps, in that area.

So there’s all these different techniques you have to combine. And of course, the use of the pressure indicating based on top of that. You can combine all these techniques to ensure that you have the correct extension. It’s not so hard to do, to be honest with you, but I totally agree that maybe the biggest problem is the lack of enough patients to be able to demonstrate all these things clinically to our students at an undergraduate level.

So in an ideal world, I would have my own complete denture patients. I would do the procedure step by step. The students would be observing. And after each step, the students would go on to their own patients and do the same thing. But this is, it’s impossible to do nowadays because you don’t, you have too many students and not enough patients.

[Jaz]
Especially fully dentures patients willing and able to come to a dental school, it’s very difficult now.

[Andreas]
Yes, connects indeed. We make sure that the fit and the border extension of our dentures are correct, and only then are we allowed to start looking at the occlusion. And it’s, I think it’s a very important step at that stage, you don’t just ask the patient to bite down.

You have to guide the mandible in the retreated position to make sure you have correct positioning, you have correct interdigitation at the desired position of the mandible. If you ask the patient to close, they might easily protrude or laterally protrude and do something like that, and you won’t be any wiser.

[Jaz]
What is your preferred technique to guide them? I’m sure you’re going to come on to this next anyway, but do you do like a, just a guide their chin? Do you get them to cover their tongue back like you did the registr- yeah, sure. Tell us what you’d like to do.

[Andreas]
The chin thrust is my preferred technique. And again, there’s many different techniques, but There, there is no right or wrong. One clinical tip, which I think is quite important in order to be able to get the patient in the retruded position in the first place is you want the starting position of the mandible to be as close to the position you want it to go, to begin with.

What I mean by that, very often we’ll have patients relaxed. We know the rest position is a few millimeters more open than the retruded position, and obviously more forwards. But I think it’s strong in that situation to ask the patient to open wide so you can then try to guide the multiple back into the hinge access movement and get it to close and get it through the position.

If the patient is almost closed, start from there. Don’t distract your patient to open as wide as they can, because obviously that will get the mandible out of the terminal hinge axis and move it more anteriorly. And then you’ll have to do extra work to get the mandible back again. So, why do that? So, patients are usually-

[Jaz]
Make sure the only slight teeth are only slightly apart before you guide them. Now, for any students listening, why is it that you like this joint position compared to any other joint position to have your patient to function and design the bite around.

[Andreas]
Don’t get me wrong. This is not my matter of preference. This is by textbook. This is the only position of the mandible that you can set up that in a complete denture because it’s the only reproducible position of the mandible. So if it was any other position, you wouldn’t be able to guarantee every time you see the patient between visits that you get them to close in the same position.

So it would be impossible to work. We do know from anthropological studies that in dentate patients, the ICP will either coincide with a retreated conduct position or may be one or two millimeters more anterior to that in a dentate subject, and then we lose patient will have no idea where the ICP used to be.

So there there’s two scenarios. Either the ICP used to coincide with the retruded contact position, in which case by guiding the, by setting up the teeth in the retruded position our job is done. Or, if the ICP used to be a little bit more anteriorly, one or two millimeters, the difference is so small that we know the patients can adapt to that. So it’s not a matter of opinion or you don’t have a choice where you have to set up the teeth for complete dentures and get it through the position.

[Jaz]
I’ve heard before, and also in the comments on YouTube. I’ve seen one patient that is for under a consultant like clinic at Guys when I was doing my DCT where one patient just couldn’t tolerate it.

He just couldn’t tolerate and maybe he had a big slide in his past. Maybe he had a very large slide. Have you found a patient who just couldn’t tolerate the retruded position and then you had to pick an arbitrary position to set things up? Because that’s the best that you could do. Has this scenario ever propped up for you?

[Andreas]
I haven’t come across a case like this luckily enough. So.

[Jaz]
Thank God. Yeah. I’ve only had it. I’ve only seen it once and that was like a nightmare to do. So yes, you need a reproducible position to work with that you can guide the patient. So yeah, that is the, hopefully none of you see a patient like this.

[Andreas]
Yes. Because it’s the practically very difficult or impossible to proceed with a situation like this. I would have thought in a case like this, it might make sense to consider a non anatomic case like a monoplane occlusion to allow them some leeway around there.

[Jaz]
Yeah.

[Andreas]
Some freedom of movement.

[Jaz]
Fine. So we’re now, we know you’ve answered why we detect what recommends using a reproducible position and you’re going to guide the patient. You’re using the chin lift or the guiding the chin a little bit. Is the curling the tongue back, what do you think about that technique as an alternative technique?

[Andreas]
I don’t think there is a right or wrong technique. It’s a matter of personal preference and it’s a matter of what might work with your particular patient. I mean, we all know there are some patients who may prove a little bit harder to get into the position. But to be honest with you over the years, I haven’t found many cases where that proved to be such a big challenge that so as to make it insurmountable.

I mean, it’s just a matter of practice. It’s a matter of getting your patients relaxed. And many times it’s a matter here’s another clinical tip of, don’t say anything to your patient. Don’t tell them. Well, I want you to try and put your mouth as far back as you can or something like that because patients will try to help.

And by doing so, a lot of patients will actually protrude the mandible rather than relax and allow you to guide them into their true position. I don’t tell them anything. I just a good grab of their chin and tell them, let me close your mouth. That’s it.

[Jaz]
Good. That is a top tip right there. Brilliant. And once they close together, let’s say that, how often is an interesting question. How often would you expect with your level of precision or whatnot, how often would you expect things just to be absolutely perfect and you’ve got contacts on both sides, left and right? Or do you think there’s a, usually some adjustment to do once you’ve guided that chin and you get them together?

Is there any adjustment to do? Obviously this varies a lot on the quality of the bite registration, the skill of the dentist, the skill of the technician but I know what you do is, is a much higher level. I believe from what I’ve heard about you, Rupert talks so highly about you and what he says and you taught him a lot, inspired him.

So obviously you’re much more experienced. What about for the inexperienced dentists? Would you think they’re expecting to do some adjustments?

[Andreas]
I think it would be sensible to expect to do some adjustments, but I think the best tip is to prevent getting yourself in that situation in the first place. And there are ways to do that. And obviously the more time you spend at the georegistration appointment, I often tell my students that it’s perfectly fine to use two visits for the jaw registration, simply because it’s too much to do. It’s too much for the patient and it’s too much for the operator as well. And it’s quite absurd to expect someone with very little experience in complete denture prosthodontics to do all of that in a single visit.

And the thing is that the longer you take, the more tired the patient gets making everything even harder. Then the wax starts getting softer and things start moving around and it becomes a nightmare. So don’t put yourself in that situation in the first place. So my advice is that, and this is not my personal technique, this is the way we were taught at King’s at the postgraduate program.

To actually split the workload over two visits. So the first tip is that you really need to have a well supported, stable, and retentive basis to do the jaw reg accurately. And the best way to do that is to go for permanent basis. Permanent heat polymerized PMMA bases, not record bases, the reason for that is-

[Jaz]
So the record bases are the wax ones, right? Or shellac base. Is shellac base count as a sturdy base, or is that still a temporary?

[Andreas]
That would still count as a temporary base. So we were taught that Kings and we were teaching, and I’m still teaching to use permanent base material. The reason for that is any kind of record base, whether it’s wax or shellac or acrylic or the light polymerized stuff.

In order to be able to retrieve it from the master cast, you need to block out any undercuts. Otherwise, either the base will get destroyed or the cast will get destroyed. Which means if you have blocked out undercuts and when you place it in the patient’s mouth, it’s possibly not going to be retentive.

And you don’t want to have to do all the difficult steps of the jaw registration while having to hold the denture in position as well with your fingers. It would have been feasible if we had 14 fingers instead of 10, but we don’t, so we have to deal with that. Because imagine that, trying to hold the upper base in position, trying to hold the lower base in position, and trying to grab the patient’s mandible and guide them into retruded position as well.

You just need more fingers. So, since we ran out of fingers, the next best thing to do is to go for a permanent base. So, the first thing you need to do on the jaw registration appointment, if you have prescribed the permanent bases, is to ensure exactly the same way we mentioned earlier about the finished denture.

Make sure they have a good fit, they’re comfortable, they’re correctly extended. And if they don’t, there’s plenty of time for you to do something about it. Later on, before the denture is finished.

[Jaz]
Before we continue with that now let’s say someone has gone for a temporary base. So it’s like wax or shellac or whatever, and they’re struggling to keep it in place. And now they’re in this rubbish scenario. Could they use a denture fixative, denture adhesive to just give them a bit of a help in keeping the base secure? To aid them with a jaw registration?

[Andreas]
Definitely. It’s definitely better than nothing. But on the other hand, this will only address the lack of retention. If your denture’s base is unstable as well and it can move at horizontal level, It might even contribute to some error because it will have to do with exactly where you position it in the patient’s mouth and hold it in that particular position. Now, don’t get me wrong, I’m not saying that you, if you use temporary bases, record bases, it doesn’t necessarily mean that your finished denture will be unretentive.

It’s just that you won’t know until the denture is finished. And you don’t want to have that kind of surprise at the placement appointment. And also, it’s not nice for the patient as well, that they’ve been waiting for such a long time to have their final dentures, and on the day that you’re supposed to give them the dentures, what you may end up doing is taking a big bear and grinding lots of acrylic out of the nicely polished dentures, that they just expected to be just fitted, and that’s it.

So, by using permanent bases, you can do all the work at an earlier stage, when the patient actually expects you to be doing stuff, and they don’t even know that this thing you’re working on is going to become their final denture. So, they will not even notice that you’re doing anything, and they won’t mind.

And it also makes the placement appointment much easier because you’ve already done most of the work and you will know that your dentures will be retentive, they will be stable, they will be well supported. And all you have to worry about is the occlusion. Okay. But we’re getting carried away. Let’s go back to the jaw reg appointment.

So, the first thing I recommend is to prescribe permanent bases and then you carry these over to finish. So if you have permanent bases, you adjust them, you check them first and make sure that they’re fitting correctly, they’re retentive. So the next thing you need to do is to start working on the upper denture and establish the lip support.

This is very important because the amount of lip support is one of the most reliable clinical indicators about the position of the anterior teeth. We have all these guidelines we use in the lab, like the position of the incisive papilla, et cetera, et cetera. But clinically, the most reliable guide is the lip.

If the lip looks normal, it’s a good indication that this is where the upper teeth need to go. So you have to establish the lip support and then decide on how much tooth you want to have showing the anterior incisal edges. You cannot do it the other way around because obviously changing the position of the wax stream in the anteroposterior direction will affect the amount of tooth showing as well.

So you will end up going around in circles. So establish the lip support first, and then you check. And we know that for most people you want to be showing one or two millimeters of wax below the upper lip. Now, this is important.

[Jaz]
At rest.

[Andreas]
At rest, yes. At rest. This is important because it will not apply to everyone. I mean, some people, naturally, when they are at rest, they will not show any of their upper teeth. Some people will show one third of their upper teeth. So, you have to judge it on the case per case basis. So, once we’ve established the amount of teeth showing as well, then we can use fox’s bite plane to establish the orientation of the occlusal plane.

The amount of teeth showing will give us the level of the occlusal plane, how high or how low it’s going to be. And then we use the ala tragal line and the interpupillary line as a guide, assuming the patient does not present some gross facial asymmetry. And I say this because I deal with these cases as well, so it gets a little bit trickier.

So in most patients, you want the occlusal plane to be parallel to the ala tregal line and the interpupillary line. So once, once you’ve done all that, you don’t want to mess with the upper rim anymore. You want to leave it alone and only work on the lower rim. So then we place the lower denture in the mouth again.

We make sure that it’s well fitting, it’s comfortable, it’s correctly extended. And then we, before we start measuring anything, we need to make sure that the two wax rims, the upper and the lower rim are parallel to each other, so when the patient is biting down on them at any OVD, that they will have good contact throughout their whole occlusal surface.

[Jaz]
Rather than just hitting at the heels by the molar.

[Andreas]
Which is what happens normally.

[Jaz]
Classically.

[Andreas]
Yes. And yeah. The reason this happens is that dental laboratories tends to overbuild the wax streams and they tend to overextend them posteriorly. I mean, you’re not going to be replacing the third molar, so I don’t need any wax to be there in the first place. It’s fine that they do that, and I understand that the reason they do that is because it’s clinically easier to remove wax to add wax onto the rim.

It’s simpler, you just use a hot spatula and it’s much quicker. So it’s fine that they do that, so long as we’re aware that we want the rims to occupy the space that the natural teeth eventually will. So we don’t want the rims to be too thick, we don’t want them to be too high. So, once we make sure that we have contact between the rims, we can make an initial measurement of the freeway space.

And if we find that we have a little bit of freeway space, we can just take a quick jaw reg there and then, and then stop, let the patient go. So we’ll establish the lip support, we’ll establish the level and the orientation of our occlusal plane, and all we want to do is make sure that we have good contact between the rims to take a quick jaw reg. We let the patient go, and we take our working cast and we articulate them. We mount them on the articulator with this quick jaw reg.

[Jaz]
I just want to pick before you continue, because there’s that little nuance bit. Different ways of registering the upper wax rim and the lower wax rim. One way that I initially learned was making little notches in the lower, and then squirting PVS.

But then another cool way, which I really liked, Sarah Tubby showed me, is getting the wax knife and twisting it to make like a little cup or a dome inside the lower rim. And then the PVS material will actually sink into the dome and have like a positive so that it is easy to seat the wax the PVS registration with the wax rim basically.

Are there any ways that are superior? Are there any ways that you like to record or teach the recording of the upper and lower wax rims?

[Andreas]
Look, there is no right or wrong answer here. Again, it’s different techniques. As long as you manage to locate and lock the upper with a lower rim, that’s all I care about. I don’t mind if-

[Jaz]
What do you think about squash bite then? Just heating it and just get them to bite together and the wax is stuck with the wax. What do you think about that way?

[Andreas]
This is not a good idea. And I mean, it might work in some cases, but you have to account for the displaceability of the mucosa. So you can never ensure that the wax is evenly sheeted throughout the whole surface. In which case that would not matter, so you might end up with tipping one of, usually the mandibular denture, mandibular one. So it might tip during the actual registration. So, this is not recommended. People have to understand, I believe, that the wax on the wax rims is not our registration material.

This is just a block that is meant to support our registration material, whatever that may be. Whether it’s heated wax, or whether it’s zinc oxide and eugenol base, you can use that. Whether it’s silicon registration material. Any of the materials are fine, each one has its own advantages and disadvantages, for example, silicone is much easier to use.

You just press the button and it comes out. But you have to be quick because they are fast setting materials. Zinc oxide and eugenol is very rigid, so I like that. But it takes ages to set and your patient might slightly move while you’re waiting for it to set and you don’t want that either. Wax, you just have to get it at the right temperature, and if you do, it works beautifully.

But then again in a country like Cyprus you don’t want to use wax for your jaw registrations, because during transfer from and to the laboratory, things may go wrong. It gets really hot outside. So I always teach my students while at uni, try all the materials available, and see how they work, and see which one works best for you.

With regards to what kind of shape you’re going to cut onto the wax rims, whether it’s a notch, or a box, or a little groove, or whatever it doesn’t, I don’t think it makes a huge difference. So long as you have some kind of feature to be able to locate the two rims together. Here’s another tip for you.

What I like to do is apply after I cut my notch, I go for notches. Just make sure they’re not parallel to each other, because that may allow the rims to slide sideways. You know what I mean? You have to make sure that they’re not parallel. And then I apply a thin smear of Vaseline on one of the two rims.

And then if I’m using PVS, I will use a bit of tray adhesive for silicone onto the other rim. So I know that my jaw registration material will stick securely on one of the rims but will be easy to remove from the other. So I might struggle otherwise to remove both dentures locked together from a patient’s mouth.

It’s not very comfortable always if the patient has a small mouth opening. But this way I can separate and remove them individually and reassemble them together. And then you have to check, you have to check that they lock securely in place. And you have to allow your patient to rest a little bit, maybe have a quick rinse and put them back in the mouth and guide them again into the treated position and make sure that they will go straight into the same position.

And because if they don’t, obviously you have a small error there. But as I was saying, if I’m doing the two visit technique, I’m not going to bother too much about that. I just want the quick registration without being too fast about the OVD either. You want the quick registration to mount those wax bases with the working cast.

And then on the articulator, it’s very easy to make sure that they’re perfectly parallel. You have perfect contact between them throughout the whole surface, which I think is important to avoid introducing errors. And then on the second visit you get the patient back in and then you have the lip support and the occlusal plane ready.

You can do a quick check again to confirm that the patient is happy with this amount of lip support and this amount of tooth showing.

[Jaz]
But what are you getting from the lab though for the second time? What are the lab have they added anterior teeth only? What have they done?

[Andreas]
You can set up some anterior teeth if you want to, to check the aesthetics and your tooth mould selection. But you haven’t done that part already. I’m talking about undergraduates level. Okay. Or your first few cases. So what I will ask the lab to do or what I will do myself is articulate the working cast and make sure my wax streams are perfectly parallel and I have perfect contact throughout the whole occlusal table. That’s what I will ask. And then I will get them back. I will place them in the mouth and then I’ll just do a quick check on lip support and the amount of tooth showing. And then I’ll start measuring the OVD.

And it becomes much easier to establish the OVD if you know that your rims can make perfect contact throughout their whole surface and it’s much easier to avoid introducing any errors. So, on the second appointment we will do just that. We will do the actual jaw ridge and we will mark the midline and make sure that during the jaw ridge the midlines of the upper and the lower match so we know we haven’t introduced a lateral error.

You can build up the lower rim to be at exactly the same level in the anterior posterior direction with the upper one so that allows you also to check that you haven’t introduced an anterior posterior error. I don’t know if you follow me.

[Jaz]
I follow you. I’ve never done that before because my worry was that I thought that whatever AP difference you have between the upper wax rim and the lower wax rim will dictate the insides of classification. And by having the wax almost like class three.

[Andreas]
That will give you the overjet that you want. But what you can do is after you’ve established the overjet that you want clinically and you check the lower lip support as well and make sure that the lower lip sits at the right position as well. You can use a different color wax and add some extra wax on the articulator to make the anterior, the leading edge of the lower rim, level with the maxillary one.

So then when you take this back into the mouth and you do the second part of the jaw edge, you will be able to see whether they’re too much exactly. If you see the lower rim being more anteriorly, you know that you have not achieved the retreated position of the mandible. So that’s another way. The patient has protruded.

And by using a different color wax, then you can easily just remove it before setting up the teeth. Or if you, you can, you can measure the overbite, the overjet that you wanted and then instruct the lab that, where I have my watch rim on the lower, I want you to set up the lower teeth two millimeters more posteriorly, for example.

This is another, that’s another way of doing it. Another tip that I would like to share for the jaw ridge is that once you’ve done all that and you’ve marked the midlines and the glusal rims are perfectly parallel and you’re ready to do the jaw ridge, don’t apply the registration material throughout the whole occlusal table.

I only apply the registration material from canine backwards to the molar. This way I can observe clinically with my own eyes that the two wax streams are in contact. So I know my patient is fully closed in the right position and I can see the midlines that I carved that they match perfectly.

[Jaz]
So you have two wax, you have a left bite and a right bite essentially.

[Andreas]
Yes. Yes. But you have to be a bit careful if you’re using silicone for registration, that if you do that, that you have a bit quick because it sets so quickly. You don’t want to open, to end up with an open bite. But again, you will be able to, at least you will be able to see what’s going on before you remove this from the patient’s mouth.

So if need be, just repeat the process. Another trick I found out, I realized about that recently is that you can use a transparent jaw registration material which is used for transferring mock ups with composites and things like that.

[Jaz]
Exaclear, Memosil, these kinds of things.

[Andreas]
Yes. And you can use that. So you can actually see through the registration material that you have perfect contact of the wax streams clinically. And I use that a lot in partial denture cases to make sure I have natural tooth contacts where my patient is biting. So I found that to be very useful. So yeah, I mean it is feasible to do all of that in one visit, but if you’re inexperienced, if it’s your first few cases at an undergraduate level, I prefer my students to do it in two visits.

I prefer them to get things right rather than trying to do everything quickly and then have to go back.

[Jaz]
Agreed. It’s a lot to think about with the aesthetics and they say that a great way to learn cosmetic dentistry is by doing complete dentures. Complete dentures will teach you how much tooth display you have, any nuances you want to put in.

Cosmetic dentists learn complete denture aesthetics first because you get to play and set everything, the right AP level, the right vertical level. It’s a good thing to do, I think.

[Andreas]
I totally agree with that. And I strongly feel that even if we end up in a world with no dentureless patients seeking the conventional complete denture treatment, we still should be teaching some of the complete denture stuff, particularly about the tooth setup.

This is very important. And all that knowledge can also apply to planning cases for implants digitally. If you know how to do a tooth set up, you can use that to plan implant cases. And again, it’s very important. Going back to your initial question about how to avoid getting yourself in a situation where you’re placing the dentures in the patient’s mouth and you have like a big open bite or something like that.

So the first step is to ensure, to do all the things we said to make sure that your jaw reg is correct in the first place. The second thing is to realize that the trial insertion appointment is very important and the trial insertion appointment that you do after the jaw reg, realistically your first and your best chance to confirm that the georage was correct.

Because when you have to deal with two blocks of wax, which are perfectly parallel to each other. It’s easy to have a small slide and it’s easy for it to go and detect it. But as soon as you have some cusps on the teeth, as soon as you have some anatomy, it becomes very feasible clinically to be able to detect if there is any interference in the path of closure.

And at that stage, if there is, it indicates that you did an error in the jaw reg. So you will be able to feel and you will be able to see the first contact when the patient is guided into the retreated position. And you will be able to feel and to see a slide either in the anteroposterior or the lateral direction and you can measure it as well.

And the direction of the slide will be an indication about the direction of the error you had as well. So at that stage, it’s very important not to rush things, not to get carried away, not to give into patient pressure to have these things finished as quickly as possible, but to take the time to correct the job registration before you proceed.

[Jaz]
I mean, in this scenario, if it’s a very minor discrepancy and I’m no expert in complete dentists at all, I’ve had a little bit of training in DCT posts and stuff, but it’s not something I do very regularly, but, the way I’ve managed it in my novice hands and complete entries is by, if it’s a very minor prematurity, just like a little bit, I might just heat the wax around that one tooth or that region and and guide the patient again to close in and let that tooth just intrude a little bit and get the balance.

Is that a good way to do it? Is there a better way to to try and correct it? Because the other way I’ve done before we cover all the ways is if it’s a big discrepancy, I’ll do a pre centric check record. So I’ll basically record the bite around that massive interference and let the lab do it on the articulator. So tell me about the different ways to correct this at the try-in.

[Andreas]
Absolutely. There are many different ways to correct it, but it all depends on how big of an error you have to deal with. So how do we define a bigger? If you look at the old textbooks which I totally agree with, an occlusal error is considered to be substantial if it’s wide, if the slide it causes is wider than a third of a molar cusp width.

So we’re talking about any, any slide that is more like half a millimeter, 0.7, one millimeter, that is big enough. So then you have to decide, you have to observe what’s happening clinically and determine whether it’s just that one contact or one particular tooth, in which case. The most sensible approach, yes, is to reset the tooth, or if you have several of them, which indicate a lateral error in your jaw registration.

In which case you can take a pre contact record and send this back to the lab to reset the teeth, or you can repeat the jaw ridge after removing the ascending teeth. So usually, if you have an anteroposterior error, it will be all the posterior teeth. So you can start by removing all the molars and see if the patient can be guided into a retruded position correctly.

If not, you remove the premolars as well. And from one of the two dentures, you don’t have to remove them from both of them. Okay, and just replace them with wax and repeat the jaw reg. And now you will have the teeth set up, you’ll have the anteriors to show you that during the, the new registration, you will have the correct, the anticipated overjet, you will have the midline matching.

So it’ll be much easier to correct this in this way. And then just send the dentures back to the lab and ask them to reset the lower teeth. Now, depending on your level of experience and comfort, you can either then proceed straight to finish. If you’re a hundred percent certain that everything was done correctly, or if you’re not a hundred percent, the recommended approach is to repeat the trial insertion just to confirm that the georage was correct.

I think it’s time well spent because it will save you trouble later on. So that the trial insertion is our best chance to confirm the georage. This is very important for people to realize before we even start looking at things like the aesthetics or speech or anything like that. This is the first thing I always do.

But it’s at the wax jaw restoration and at the try in where you confirm it, where you’ve made a decision whether your patient’s incisors are going to be class 1, class 2, class 3, or even are they going to be in complete overbite or incomplete overbite? What is the recommended way to do it best for your patient in front of you?

This is another very important and big topic you touched upon earlier and we forgot to comment on that because we got carried away. I strongly feel that complete dentures should try to replicate their natural tooth positions the way they were. Because if you think about it, what is our aim in providing people with complete dentures?

What are we trying to do? Why do we do it? We want to restore the function of mastication, we want to restore speech, and we want to restore the aesthetics, the normal appearance as it was before those teeth were lost. The easiest way to do that is by setting up the denture teeth in the initial positions that the natural teeth used to occupy.

So this means that when you have a class 1 case, you need to go for a class 1 setup. If you have a class 2 case, you have to go for a class 2 setup. If you run out of-

[Jaz]
Are you talking about the skeletal class, right? Skeletal class is what’s guiding us.

[Andreas]
Yes. So if you run out of space, you might have to drop a second premolar from the lower jaw from the lower denture in a class 2 scenario.

Now, if you have a class 3 case, that’s where things become interesting. It depends on the magnitude of the discrepancy between the two jaws, but in some cases you might be able to get away with it by setting the teeth as an edge to edge position by proclining the upper anteriors a little bit.

This might work, you might get away with it. But if you have a huge discrepancy, I mean you have to go for a class three setup. It’s not going to work otherwise. The upper lip will be pushing the upper denture downwards. And even if we were able to do that, the patients will not be able to function properly because the way they have learned to function throughout their whole life was as a class three.

So there’s no point trying to correct that because it’s not something that needs to be corrected. That’s how the patient’s teeth used to be in the first place. Now this should become apparent at an earlier stage at the jaw reg when you’re trying to adjust the wax rims the way you want them.

This should become apparent and it should be taken into consideration when doing the georage. If for some reason you haven’t detected that, it will become apparent at the trial insertion. When you do the phonetic tests, when you try to confirm the freeway space, when you look at the patient’s aesthetics, it should become apparent that something is wrong.

And in some cases, it will be just that you were trying to rehabilitate someone at class one, whereas they used to be at class two. So that’s not going to work. So you have to go back.

[Jaz]
I think it’s an easy beginner mistake to make. And I may definitely made it before where you think, automatically you think everything should look like someone just finished orthodontics and that’s the way.

What about, obviously the skeletal class will guide this as well, but let’s get talk about the nitty gritty of the occlusion. Should the anterior teeth touch in a complete denture? Let’s say, let’s go with a class one because obviously if you’ve got significantly class two one, we know the anterior teeth won’t touch.

So if you’ve got a class one, do you like for there to be centric stops on the anterior denture teeth or just keep them on the posteriors?

[Andreas]
On the posteriors. I think it’s sensible that if you have a very tight occlusion and you have occlusal contacts and they’re on the anteriors as well. This means that the moment the patient starts to make a small slide in protrusion, it will apply forces trying to destabilize the denture.

So you don’t want, you want to have a little bit of freedom, but not much like 1. 5 millimeters should be enough. You don’t want more than that. Now, there’s a problem here that a lot of patients, obviously, are not familiar with prosthodontic concepts, so they might not be happy with that.

They might feel that I have a gap at the front and I can’t bite. So it’s something that has to be explained to the patient at an earlier stage. And of course, again, it has to be judged on a case by case basis. I mean, if you have a case with plenty of bone and a big ridge and you don’t expect to have any stability issues, you might be able to get away with it by having anterior contacts as well in ICP. But if you have a case with a lot of resorption, this becomes increasingly important to allow them a little bit of freedom of movement in the anteroposterior direction.

[Jaz]
Have you got time to discuss the balanced occlusion and lingualized occlusion?

[Andreas]
I have, but I warn you that this is a discussion that may take another hundred years, but-

[Jaz]
Let’s try and do it in 10 to 12 minutes. Let’s try and do the service.

[Andreas]
10 minutes about balanced occlusion.

[Jaz]
An introduction to it. An introduction to it. Let’s try it. Balanced occlusion, as far as I know it, is a fundamental thing. It’s a patient with a complete denture, bites together. Both sides, as you said, the molars, premolars, hit at the same time.

That’s a fundamental truth I think we can all agree with, that they must hit, you don’t want one side hitting, then the second side hitting, that’s going to destabilize the denture. It’s a very basic concept. But what are the other guidelines that we should be using on complete dentures when it comes to balanced occlusion?

And then I want to talk about lingualized occlusion. What is it? And is this the way that, because the textbook, I think there’s three or four different ways to set up your denture articulation movements, which is the accepted way that you follow. Following on from that.

[Andreas]
Okay. First of all, let me say this, that there’s different, as you said, different occlusal concepts. Okay. So you have a balanced occlusion, you have lingualized occlusion, and you have a unbalanced occlusion or group function. And then you have monoplane occlusion. We can forget about monoplane occlusion because no one’s using it anymore because-

[Jaz]
What is, just explain what monoplane is.

[Andreas]
Monoplane is when you use non anatomic teeth which are completely flat and posteriorly. So the problem with that is that the forces transmitted through the denture to the underlying ridge have been shown to be of greater magnitudes because of the flat occlusal anatomy making it harder to penetrate through the bolus. So it’s something that is not really used nowadays that much.

So I don’t think it’s very relevant. As far as balanced occlusion is concerned, again, this is just my personal opinion based on my teaching and all the readings I’ve done, but it is not considered necessary. Why? Well, first of all, let’s say what balanced occlusion means. It is defined as a bilateral, simultaneous, anterior and posterior occlusal contacts of the teeth, both in centric and eccentric position.

And it’s a biomechanical concept that its primary aim is to enhance stability of the dentures in function. So here is where the, I mean, it makes perfect sense as a mechanical cause, but I fully agree with that. But here’s where the criticism starts. And go back into the sixties and seventies, the famous quote by Sheppard that enter bolus exit balance.

What does this mean? That the moment you have a bonus of food in the working side is the mandible is trying to close on the working side. The teeth on the working side will come into contact with bolus long before the teeth on the non-working side will be anywhere near making contact. So it means that the masticatory forces will start being exerted from the bolus to the dentures on the non working side a long time before any balancing contacts are even there.

So if there is any issue with stability, this will materialize as well before those balancing contacts happen to help stabilize the, the lower denture. The second-

[Jaz]
And just to make balance tangible on the articulator, you try and set this up, and for those who follow it, they do it on the patient’s mouth, so that, if the patient is grinding to the right, the working side, the right side, are touching, but also the left side are still touching, so that there’s no tipping. Is that what we mean, right?

[Andreas]
This is what balance postulates, that you should have contacts on the non working side as well, to help stabilize the denture. Now, there’s other issues with that. Now you mentioned articulator. So, I know this is a huge discussion, but it is a fact that articulators do not represent 100%, cannot simulate 100 percent accurately the function of the stomatognathic system.

We know that for a fact. I mean, it’s a close approximation and it’s a very good effort at that, but we know nowadays that the mandibular movements are much more complex in nature than the simplified concept of the articulator. So, for example, what used to be the concept of the hinge movement of the mandible has been rejected because we know nowadays from clinical studies that there are instantaneous centers of rotation.

So for every given position of the mandible, the center of rotation of the mandible changes because the whole mandible moves as a rigid body that it is. So the question is, when you do your complete denture case, do you use a fully adjustable articulator? And if you do so, do you use a pantograph as well to determine the exact point of rotation?

And then you will spend the time clinically to take all the patient records, the protrusive records, lateral records. And go back to the fully adjustable articulator and apply all the settings for that specific case. Because I don’t know many people that do, and I don’t. And I mean it’s, I was actually looking if, whether I can buy a pantographic facebow and I couldn’t find one.

Okay, so what do most people, let’s not hide behind their fingers. What do most people do? They use semi adjustable articulators, which is perfectly fine. But they use them in average settings, don’t they? So it’s effectively the same as using an average value articulator. But may or may not accept a facebow rep.

Okay, so we know from clinical studies, it has been shown that use of a face bow or not using a face bow in complete dental reconstruction did not have any demonstrable impact on patient satisfaction or any improvement in masticatory performance. So we know that for a fact. So going back, you’re telling me that you try to set up the teeth in to achieve that those balancing contacts on an articulator, which is not being set up with patient specific settings and it’s effectively being used as an average value articulator.

And then you expect those contacts to be present in the patient’s mouth as well. Because the answer is they won’t. And even if they were, again, it has been shown that these contacts are lost soon after insertion. Because what happens is that you will have a little bit more adjustment of the mucosa under the occlusal loads from the new dentures, or you will have a little bit of bone resorption, or you will have a little bit of wear on the teeth.

So these supposed contacts is very likely that they disappeared soon after insertion, and all the pa-, the patient might assume a slightly different mandibular position during closure. So, that’s that, as far as the balancing contacts are concerned.

[Jaz]
Does that mean we don’t have to worry about excursions then?

[Andreas]
It doesn’t mean we don’t have to worry about excursions. It means that I think it’s a futile exercise trying to achieve that balance. Even if you spend the time to sit down with the articulator yourself and set up all the teeth to achieve those balancing contacts, again, you would have other issues.

And another issue is in what happens in protrusion. So this is a totally different situation, but what we have already discussed about. Because in protrusion balance. Occlusion postulates that you should have posterior balancing contacts bilaterally. Okay. If we look at what happens on a dentate subject when we try to protrude the anterior incisal guidance will dictate posterior disclosure.

On someone who’s a dentulous, it will be the condylar guidance that will determine the posterior disclosure because there are no teeth. So when we set up that if imbalanced occlusion to achieve these posterior balancing contacts in protrusion. It means that someone would need to have either a very steep occlusal plane, which is not realistic, or you would need to have an overly exaggerated compensating curve, or you would need to have a denture teeth with very high cusps, or you would have to reduce the incisal guidance in order to allow these posterior balancing contacts to occur. But if you do that-

[Jaz]
So basically, you’re going for the opposite of anterior guidance? You don’t want the anterior guidance to take over because that will cause a tipping forces?

[Andreas]
Yes, exactly. So to achieve balance and protrusion, it means that you have to reduce the incisal guidance by setting up the teeth with a reduced overbite and overjet overbite, the reduced overbite.

So, but this may result to aesthetic problems or speaking problems or swallowing problems. So it is very difficult to achieve. And the way they used to achieve it in the past was with a overly exaggerated compensating curves. That’s how they used to do it. Or in some cases they would have a run of acrylic behind the second molar.

And that ramp would follow the inclination of the retromolar pad, and that would be where the posterior balancing contacts would occur. So it’s not something that is practical and it takes such a long time to try to set up the teeth in balance on an articulator because of all the limitations we just discussed.

[Jaz]
But what if you sit down with your patient and you do it all on the patient, is it still worth doing it? Because as soon as you put the bolus in, then it is gone again. So is it worth even spending time with your patient to grind in the balanced occlusion?

[Andreas]
I don’t think so. I don’t think so. And I will explain to you why. Going back we said that we want to try and set up the teeth as close as possible to the natural tooth position, isn’t it? When we’re rehabilitating with complete dentures. So we know that in the natural dentition, you don’t want to have any contacts on the non working side.

These are considered interferences. These are considered pathological. So the whole concept of balance stems from our worry, our stress, that our dentures are going to be unstable. And we need to do something mechanically to stabilize them. Okay, so I think this is a, this is a negative approach. I think the best way to go on about it is to start not by assuming that you’re going to have problems.

To start building the dentures, assuming that everything will go right. And if you do all the things like the impression procedures, if you use the permanent basis, it will become apparent at an early stage whether you have stability issues or not. So when you’re adjusting your wax rims, and we said earlier that you need to ensure that the wax rims occupy the same space in the patient’s mouth that the natural teeth eventually will, then it will become apparent if you’re having any stability issues.

And then I say it’s okay to compromise and start altering these natural tooth positions, like try to get the posteriors a bit closer to the crest of the ridge, which is not necessarily the case. Try to get those balancing contacts if you have the time to be bothered by it, and this will solve the problem.

But I do not assume at the start of every case that oh, I’m going to have a problem. it’s like walking down the sidewalk and you see a banana peel and say, oh, no, I’m going to fall down. I mean, try to avoid it in the first place, try to avoid having stability issues in the first place. And this is feasible if you’re using permanent basis, because you will know at an early stage of construction, how stable, how well supported, and how attentive your dentures are going to be.

Now, in this direction, a new concept that helps a little bit to simplify things is lingualized occlusion. Effectively, it’s an evolution of the balanced occlusion. It just makes it technically. I normally go for unbalanced occlusion, I normally go for group function. So I don’t even go for lingualized occlusion, again, because it is an artificial biomechanical concept with a sole aim of trying to stabilize the lower denture.

[Jaz]
This is music to my ears. This is easier to do. And I, yeah.

[Andreas]
Let’s get some things straight. This is not my personal opinions. Okay. There are published articles in the literature. There are some there’s an amazing article by Gunnar Carlsson. Talking about different dogmas in prosthodontics.

There’s an article about complete denture occlusion, a more recent one by Goldstein. I can send you links to the references if you want. And what this study showed is that there is no evidence whatsoever. that balanced occlusion has a benefit over lingualized occlusion, over monoplane occlusion, over group function, unilaterally balanced occlusion.

There is no clinical evidence that patients are more satisfied when we employ one occlusal scheme over the other. There is no clinical evidence that masticatory performance is improved when you employ one occlusal scheme over the other. So I think the way we should interpret this because okay, it doesn’t mean that occlusion doesn’t matter.

We’ll just set up the teeth wherever you want and that’s it. The way I interpret it is this. If you spend the time, and if you know what you’re supposed to be doing, and do all the procedures correctly, and you set up the teeth in a way that you can achieve tight, correct interdigitation in ICP, you set up the teeth so that you don’t have any interferences in the path of closure, and you don’t have any interferences in the lateral excursions.

And the patient can actually have a little bit of freedom of movement in protrusion and unilateral excursion. What it means is that patients adapt so well to whatever occlusal scheme we give them, that it works. And they’re equally satisfied, whether you spend five hours trying to get a balanced occlusion or whether you spend half an hour to get a unilaterally balanced occlusion.

And this is a testament to the amazing capacity of the stomatognathic system more than anything else. But it’s true. We don’t have any evidence to support that we should be going for balance. And we don’t have any evidence against it either. I mean, don’t get me wrong, I’m not going to to be judgmental here and say that, oh, you shouldn’t be doing that, but I just don’t.

[Jaz]
But I’m for making processes easier and more efficient and just conducive to all dentists, and it just sounds like a good deal to me to go for an unbalanced group function type occlusion. But you mentioned a good point, you check to make sure that you’ve got stable bases, you check to make sure that they’re comfortable, you’ve got a nice single path of closure, so no deflection.

You’re not hitting cusps and returning back. So as long as you’ve got a nice tap tap tap on their complete dentures. There’s no movement, but then to achieve you said give them a bit of freedom. So if we look at the concepts of freedom and centric, so just some wiggle room. So instead of the the cusp or incline starting straight away having like a flat area in the middle to allow the jaw to have some space Is that the kind of teeth setups that you do?

[Andreas]
Not just what I meant was just to avoid having a denture teeth with very high cusps I mean, if you go just, I don’t know.

[Jaz]
Shallower cusps.

[Andreas]
Shallower cusps. Yes. And that’s all that’s needed. I’m not going, I’m not talking about the slat, non-anatomic teeth. I’m talking about anatomical teeth with a reasonable amount of cusp height and inclination.

Obviously depending on the case as well. But this is the whole modern approach, the Scandinavian approach of trying to simplify things and it’s all evidence based. It’s not a matter of opinion. So until the day comes that we have some strong evidence that the traditional way, the balanced occlusion is better than the others.

I don’t see any benefit in trying to teach my students to go through all that extra workload with all those extra margins of error without any tangible clinical advantage. What is the point in doing that? And again, don’t get me wrong, I don’t mean to say that balanced occlusion is wrong or that you shouldn’t be doing it.

I just don’t see the benefit in doing it. It’s exactly the same with the facebow, it’s exactly the same. So I know some of my colleagues might, they actually do hate me for that, for saying things like that, but I do teach in an undergraduate level that it’s not the material, it’s not the impression material that will make a difference when you’re doing complete dentures.

It’s not like you have to use zinc oxide and usual paste because that is the best. I mean, I have no evidence for that. And again, if you look at those same references I quoted, there are studies which show that patients would not perceive any difference between complete dentures made with falgenate or silicone or zinc oxide and eugenol paste as a secondary impression material.

So again, it doesn’t mean to say that you can use whatever you want and won’t matter at all. What it means is that if your impression is correct, if it’s correctly extended, if it’s the borders of your impression tree are correctly extended, have the correct morphology, both things will work. Silicon will work. Polyether will work. Zinc oxide and hydrogen will work. As long as you know what you’re doing and you designed your custom tray accordingly.

[Jaz]
If I summarize it, there are so many different things to look at to get a successful denture and the occlusion will not be the be all and end all. The occlusion, as long as you take some care to make sure there’s no deflections, a nice bite left and right, and then you don’t go for overly crazy cusps, and you have a good patient that can adapt, then I think that is a sound like a winning formula to me.

[Andreas]
The patients do that this has been proven beyond any doubt. It’s not, again, it’s not my personal opinion, so I’m stating here, there’s these clinical studies would show that when the complete dentures were rated by patients and prosthodontists, there was a perfect agreement, there was very good agreement between them when a denture was bad, but there was no agreement on when a denture was good.

So effectively, this means, I mean, some of these studies were done at guys as well. Mike Shannon was a lead of on many of those papers. Patients can easily adapt to a wide variety of different denture construction techniques and occlusal schemes and impression techniques, so long as we avoid significant errors.

So this is a struggle, not trying to achieve perfection because we cannot with a complete denture, but trying to avoid any significant errors and the stomatognathic system is such an amazing device that it will adapt to it as well. And hence most patients function adequately with their complete dentures and they’re happy with them.

Of course, there is a small minority. I mean, I couldn’t give you a figure that will apply universally, but at least I know in my personal experience, it’s a very, very small minority of patients can never get used to a complete denture. And the simple explanation for that is simply because they don’t want a complete denture to begin with.

And it’s perfectly understandable who would blame you for that. And we have to, I don’t know how much more time we have, but we have to discuss a little bit about the McGill consensus as well, because we’re talking about all these things. We’re talking about occlusal concepts.

[Jaz]
Yeah, I mean, we’re talking about occlusal concepts, but the McGill Consensus was a big thing that really changed the standards, I guess, right, that we’re aiming for.

[Andreas]
Yes, because we were talking about occlusal concepts which were developed over a hundred years in order to solve the problem of instability of the lower denture. And now we’re, for the last 20 years now, we have been practicing in a world where we say that we shouldn’t even be offering conventional complete dentures to a dentureless patient.

Unless it’s a strong medical contraindication or something. So as soon as you have a mandibular twin plant retained overdenture it throws everything out the window, and so far as our concerns about instability of the lower denture. So, why not try to recreate a more naturally occurring occlusal schemes like group function or even canine guidance?

I mean, there are studies which show that conventional complete denture wearers were equally happy with canine guidance than they were with balanced occlusion. They didn’t have any functional issues with it. So yeah.

[Jaz]
I’m glad we talked about this very controversial topic occlusion in inclusion any part of dentistry can be controversial. But I really like that you gave some real world advice and I think there’s something that we can all go away and practice and think about it’s definitely helped me and setting up the occlusions complete dentures.

I I do sometimes get carried away trying to do all the lingual eyes occlusion and stuff. But we’re saying there’s no real evidence to support it. And so I’m going to allow my patient to have a period of adaptation because they can. Andreas, thanks so much for giving up your time today. We obviously went a deep dive into complete dentures and we only barely scratched the surface.

I appreciate that. I would love to have you back again one day to do talk about partial dentures and occlusal set ups with that. Before we say goodbye to you, tell us more about how, if anyone wants to send some work to you, to your lab, any educational things that you have going on that we can learn more from you?

[Andreas]
Maybe I can give you a link to an email address so someone can communicate with me and depending on what way I may be able to help, I will be happy to.

Jaz’s Outro:
That’d be great. So if you send that over to me and I’ll be able to pass it to anyone who needs it. But we’ll welcome you back. Have a lovely rest of your day. I hope you get some video game time tonight and enjoy your time in sunny Cyprus, my friend.

Well, there we have it guys. Complete dentures made way easier. Thank you so much for Rupert for recommending Andreas to come on the show. He was brilliant, wasn’t he? Like so many different gems that we can apply straight away.

Kind of like myth busting and overcoming some of the previous dogmas in removable prosthodontics. Since you listened all the way to the end, why don’t you answer a few questions? Get that CPD on the app. As always, you can access on the website www.protrusive.app. Or by iOS and Android. It’s actually easier to make your login and sign up via the laptop, and then you can use that same login on iOS or Android.

For any of the resources that we promised, they will be in the show notes below. And if you have made it all the way to the end, let me know by giving this video a thumbs up on YouTube, or if you’re one of the audio listeners, then I’d love to read your reviews. I’d really appreciate that. Thanks so much for listening all the way to the end.

Once again, I’ll catch you same time, same place next week.