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Functionally Generated Path Technique – Conforming to Funky Occlusions – PDP168

A single crown being fit in a Class I, canine guided occlusion is a piece of cake when it comes to the occlusion, but that same crown in a Class II Div 1 or AOB patient can result in occlusal errors. This episode is all about sharing a classic technique to prevent occlusal issues in ‘funky occlusions’.

Join us on this special episode as we delve into a game-changing technique – the functionally generated path technique – with the experienced and generous Dr. Tom Bereznicki. Having recently stepped into clinical retirement, Dr. Bereznicki remains a powerhouse in the education scene.

Watch PDP168 on Youtube

Protrusive Dental Pearl: Ensure you have an excellent relationship with your dental technician. – Working with a ‘big lab’ can sometimes have its issues. Try to visit your lab and become a familiar face so you have your specific technician that you can ask for whenever you send any indirect work. In that way, you can grow together  – with that level of communication, the level of work you get back is so much better.

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

Highlights of the episode:

  • 00:00 Intro
  • 2:06 Protrusive Dental Pearl:
  • 4:06 Dr. Tom Bereznicki
  • 10:16 Functionally Generated Path Technique
  • 16:42 Lab Processes that might be beneficial using Functionally Generated Path Technique
  • 19:47 Protocol for using the Functionally Generated Path Technique
  • 32:48 Functionally Generated Path Technique VS Custom Incisal Guidance Table
  • 34:31 Functionally Generated Path Technique on a single unit restoration 
  • 38:07 Final remarks
  • 41:11 Outro

Did you know? You can get CPD from the Web App or Phone App and watch premium clinical videos, for less than a tax-deductible Nando’s per month?

If you liked this episode, you will also like Philosophy of Functional Occlusion with Riaz Yar – PDP066

Check out Dr Tom Bereznicki’s website!

Click below for full episode transcript:

Jaz's Introduction: Have you ever got a crown or an onlay back from the lab and tried it in the mouth and thought, whoa, the occlusion is just way off.

Jaz’s Introduction:
Either it’s in infra occlusion, it’s not even in the bite at all, or it’s in supra occlusion. It’s going to need a lot of time to adjust to get it happy, both in the static, the tap, tap, tap, and in the dynamic. i.e. the lateral excursions.

And sometimes it’s a painstaking process where we try and get this crown perfect and happy in the patient’s bite and then the patient’s perception comes into it and there’s other protocols that we talk about in other YouTube videos and episodes that I’ve done about checking the occlusion.

But this episode is about how can we prevent this scenario from happening. Well, you have to first think about when does this scenario often happen? Well, it’s more likely to happen in funky occlusions. And guess what? Loads of our patients have funky occlusions. That’s AOBs, cross bites, class 2 division 1s, and super, super deep bites, right?

These are classified as funky occlusions, but they’re actually very common in the real world. And it’s because these occlusions are not your standard class one, that the articulators that we have, whether analog or digital, they struggle to recreate the patient’s jaw movement. So this is why the problem exists, and it’s more often in these funny occlusions.

Well, Protruserati, my name is Jaz Gulati, and in this episode, we’re going to talk about the Functionally Generated Path Technique, whereby we can use this little simple trick to get our indirect work happy in the occlusion even in the funkiest of occlusions. I’m joined by a really giving dentist who’s recently clinically retired but so involved in the education scene.

His name is Dr. Tom Bereznicki. Those who go to King’s Uni will know him very well. He’s absolutely brilliant. I love everything he’s about and I want to promote everything he’s doing in education. And you know I’m a sucker for anything occlusion and promoting education and occlusion. So this topic is about how we can reduce the adjustments you do using this technique, which Tom Bereznicki is going to break down for us really well.

In the first half of the podcast, we talk about how to use this technique with Duralay and more implant work. But then I mentioned a way that we can use this technique using expired composite. And that’s more for when you’re working on teeth, like for example, broken cusps and crowns and onlays on molars.

Protrusive Dental Pearl
Before we join the main episode, I’ll give you the Protrusive Dental Pearl. Now, it’s a theme that I’ve talked about a lot before, and it is to make sure you have a really good relationship with your technician. So the person, the guy or gal who’s making your crowns and onlays. Now, this is particularly relevant in the real world, because in the real world, we need to have big labs, right?

There are big labs which keep the production costs low so that we can serve the general public. Now the issue with working with a big lab is that they have hundreds of technicians sometimes and essentially your technician is like this faceless person on the other side. And maybe you’ll never even get to know the name of the person who keeps making your crowns.

That’s really, really sad. So, how about this, guys? If you send work to a big lab, well, firstly, find your technician. But if you send your work to a big lab, then why don’t you visit your lab, right? Visit your lab and become a familiar face. Pick one technician that perhaps made a few good crowns for you in the past and say to this technician, hey, is it okay if I specifically ask for you?

Whenever I’m sending any indirect work that way we can grow together and I can send you my photos. And if you want to take it further, we can even WhatsApp exchange each other, which I highly recommend, having a technician to WhatsApp is the best thing ever. Voice notes, videos. The level of communication is just absolutely brilliant.

And the level of work you get back is so much better. So your homework after this episode is to really get to know your technician a bit better and try and build a relationship with them. And if you have a big lab that you send work to, then try and find one or two technicians within that big lab. It does mean some extra work on your part, but I promise you, it will pay dividends.

Now if we join the main episode remember we are helping to raise money for Nafisa who’s just over one year old. We’re trying to raise a million dollars so that she can get the genetic therapy and I will keep reminding this every episode.

We’re inching closer to our goal of saving this little girl’s life who’s the daughter of a dentist. Just like you, who’s a Protruserati. So remember it’s protrusive.co.uk/Nafisa. And please do go on my Instagram to see the video and my full appeal. So you can further understand who we’re actually helping and why we’re doing it. Hope you enjoy this episode and I’ll catch you in the outro.

Main Episode:
Dr. Tom Bereznicki, welcome to the Protrusive Dental Podcast. How are you, my friend?

[Tom]
I’m fine, thank you. Fine. Looking forward to this presentation. It’s the first time I’ve ever done a podcast like this, nevermind to an audience or a large part of the audience who won’t be seeing my screen. So hi, welcome.

[Jaz]
Thank you so much for giving up your time. We were having a chat before we hit the record button. Firstly, I’m amazed at how youthful you look. You’re recently clinically retired, but you’re involved big time in education, but you look great. So we’ll have to do what part of the every now and then I do an episode about health and that kind of stuff.

So I do like to ask my patients. So basically I’ve got this thing where all my patients above 60 who look great, who just look great. I do ask them. In your perception, in your opinion, what is the key to good health? And before we even start the podcast, how would you answer that?

[Tom]
Well, I’ve never been the fit, I’ve never been the healthiest of people in terms of diet. I’m not a great salad eater or anything like that, but I’ve always exercised every day. I do about an hour and a half every day. And I use that to counterbalance the fact that I quite enjoy drinking wine. I don’t drink spirits. I don’t take recreational drugs of any sort, but really just exercise.

But also I think, because I’ve been teaching a lot at King’s and have a lot of young people around me, I think that also feeds off. I think it’s very easy to sort of sit at home with your slippers on, reading a newspaper, and you just slowly decay. Whereas I’m out and about a lot, even though I’ve just stopped working. I’m still got a lot of contact with young people. I think that does keep me youthful.

[Jaz]
So contact with young people is one of the three things that I’ve been told before as a mantra of aging gracefully and being youthful for the longest time. And so the three were constantly mixing with different age groups.

The other one was keeping the brain active and continuing work. Never retire. And I know you’ve clearly retired, but one thing we’ll talk about is the amazing work you’re doing with your foundation and your website in terms of how much educational content you give out to dentists and young dentists for free.

So I definitely want to promote that anywhere we can learn. I want to promote that. So we’ll be talking about that as well. The third one is inappropriate to mention for this podcast, but if someone Instagram, I will tell you what that one was. So we’ll leave it at that. You could use it for those listening. Can use your imagination.

Anyway, you first came on my radar because I was a DCT at Guys and we never actually, in fact, I remember being in the audience and you were getting some sort of a presentation, I think, or you were very involved with the student committee. And so that your dedication with working with the students and their students union or the KCL.

So education committee, it was clear to see what you’re about your wisdom when it comes to occlusion experience. I’m very, very excited to unpack today’s topic. But I also want to just mention, straight off the bat, now that you’re clinical side, you’re putting a lot of time and energy into your foundation on you were telling me about the good work you do.

The reason you do it is to support dental students and education. Can you tell us more about your foundation, which is self funded, which is another admirable quality?

[Tom]
Yeah, I suppose a little bit of personal information for you. Really, my wife was never capable of having children. She was one of the first ever open heart surgery patients in 1954 as a child.

So we never had children, and I don’t really have any family. My wife passed away about six, seven years ago, and more recently, I’ve realized, I had to remake my will and I was thinking, well, how much money do you leave to your godchildren? How much money do you leave here? And how much money do you leave to the cat home?

And I decided that dentistry had been very good to me, and I used some spare funds that I had, I mean fairly considerable funds to start this dental education foundation. So it’s not a charity that’s looking for anybody to contribute to. Effectively, I’m just contributing to it and will continue to contribute to it as long as it needs to.

And then when I finally depart from this world, there’s a big chunk of money that will be left over in my will. So hopefully it’ll keep going for about 10, 15 years. That’s what I’d like to think will happen.

[Jaz]
This is absolutely just, I mean, I didn’t know that element and it’s just beautiful what you’re doing and I want to give it all the boost that it needs to keep going. So guys, I will put the everything, the link in the show notes. In fact, for those watching the video, I’ll be definitely putting it in the show notes and emailing all the Protruserati how they can access all your educational webinars. Some of them which piqued my interest for have been the ones about different things that can go wrong with the Occlusal Appliances.

Great series. And you obviously do some publications as well. Last year you did one about the functionally generated path technique, which you’re talking about today. Anything else that we can, in terms of resources that you put out is your website is the best place for that, right?

[Tom]
Yeah. It’s not to be confused with where I used to work. Cause it also shows up Dolbert and Tanner, but this is my private website. All the education materials free. For those that can actually see it, it’s got this on the slide, you’ve got the official website, but it’s fairly easy to find if you put Tom Bereznicki Dentist and it tends to come up.

And there’s a big video webinar section there, which has already got quite a lot of material in it. And for those of you, I think maybe the younger listeners, undergraduate, early postgraduate, I’m just in the middle of doing a 14 part series on occlusion, which you might go, why 14 parts?

Well, anybody that’s tried to read Dawson, you read three pages and you lose the will to live as good as a book is, it’s just very, very word heavy. And so I’ve broken up into working side, non working side, you name it. And if you sort of think, oh, what is a non working side interference? You’ll be able to go on the website by the new year.

It should all be on there. And you can just look at non working side interferences without having to bother about anything else. And it’s incredibly photograph driven. There’s hardly any text whatsoever.

[Jaz]
Amazing. You’re a man of your own heart. This is exactly why I had you on the show today because your interest and experience in occlusion.

And so let’s unpack that today. And obviously I’d love for people to learn from the 14 part series and further themselves in the education of occlusion. That’s really important to me and the podcast as well, that everyone levels up their game with occlusion. And so I’m excited to have a look through your stuff on occlusion as well. So today we’re talking about the functionally generated path technique. Can you just explain what this actually means before we start unpacking it further?

[Tom]
It’s really difficult because you’re not the first person to have asked me, and when I was writing, for those of you that maybe want to have a lot of detail, this was a two part article in Dental Update towards the end of 2022.

It’s there, two part. We encountered clinical problems where I worked at Darwin Tanner. And somewhere in the recesses of my mind was something from my undergraduate days, which 1976, which was the Functionally Generated Path Technique. And I don’t actually even know why we were taught it, but effectively it was using a material in usually in those days, Duralay, there are other materials today, and you put it into somebody’s mouth when it was soft.

And you’d get the patient to tap up and down, grind around. And what it would do would give you the occlusal pattern that the opposing cusps would take over the occlusal table. And it really meant the technician didn’t have to worry about the occlusal morphology because it was already done there. The only thing they needed to do is maybe put a few more fissures in to make it look like a tooth, but it wasn’t additive.

The technician wasn’t allowed to add. They just could reshape the tooth to make it look more of the crown to make it look more like a tooth. So that’s where it came from.

[Jaz]
But just on that point, Tom, let’s talk about that in terms of where it came from when you do a single unit crown, a lower molar, for example, or an onlay, which is more fashionable these days.

And you are going to take impressions for a scan, and it’s a nice occlusion. The technician has an opportunity to wax it up, or digitally wax it up, and follow the contours of the adjacent teeth, and look at the opposing tooth, and really get a reasonable guess, so that it fits first time. What kind of occlusions, therefore, do you think we need to adopt such techniques whereby we need to give the technician more clues or more information to help them to actually make sure you’re not spending hours adjusting in the chair?

[Tom]
Yeah. Well, for those of you that can’t see my screen, so if you have an anterior open bite or you have a patient with a class 3 malocclusion or a severe class 2 one malocclusion. None of these patients have anterior guidance. The guidance in ideally in anterior guidance, when you tap your teeth up and down in intercuspal, all the teeth should meet evenly.

And as soon as you move your bottom jaw forwards, left or right, you should just be on the front teeth and not the back teeth. In the case of an anterior open bite at class 3 or severe class 2 division 1, there is no anterior guidance. The guidance, the movements that the mandible makes are dictated by the shape of the back teeth, not the front teeth.

So if you’re doing an ordinary crown in an ordinary occlusion, that’s fairly easy because if you get into cuspal, the anterior guidance is not really, the guidance doesn’t come off the posterior teeth, it comes off the anterior teeth. So, really, with most crowns, it’s not very difficult for the technician to get the occlusal morphology correct to fit into the occlusal pattern of the patient.

In those cases where there is no anterior guidance, of course, the occlusal table has been worn by the teeth rubbing over themselves. And very often they also have bilateral contact. So they’re sort of grinding around on both sides of the molar teeth. It’s not a problem so long as they don’t have TMD problems.

And it’s nothing really to worry about. The problem is how do you, if you have to make a crown for somebody like that, how do you give the patient something which will fit into their posterior guidance.

[Jaz]
Can you give an example of your colleague who does lots of implant work and how this is particularly open, important and or error prone using traditional techniques in those scenarios?

[Tom]
Yes. So we had a lot of problems in the practice in around 2018, 2019. Andrew Dawood, who I work with has always been very, very upfront with all the latest techniques that came up and he started scanning implant work as well as conventional work. But when he came to implant bridge work, which had what I would call an unbounded saddle, a free end saddle, most of what was scanned and then designed and then milled when it was fitted back in the mouth was either in super occlusions, it was too high, or it was in for occlusion, which means it was too low.

As all the milling was being done in zirconia, obviously if it was too high, you would spend hours trying to adjust that which was just nonsensical. And obviously with zirconia you couldn’t just add a little bit of porcelain spath horse to it because the bond wasn’t very good, so that, or crumple off.

So that was his headache that he had. I had a headache because he’d given me a patient that was an anterior open bite and I had to restore the last molar, and the patient wanted to have a white tooth. He didn’t want to have gold, which is probably the ideal material in these scenarios where you have posterior guidance and basically this concept of the old concept popped into my head and I used that technique for my first case and it worked very well.

I mean, effectively made a posterior crown when we fitted it, having carried out this technique, it was in zirconia, I think it needed the most tiny adjustments. And that was it. It just went straight in, and it was very satisfying.

[Jaz]
It is always very satisfying when that happens, and we can try and increase the number of times that happens, and it’s especially important in these funny occlusions, where to get things right is tricky.

Now, if, before we unpack the exact technique, what are the challenges that the technician, for example, when we have these freehand saddles, or we have these AOB patients, and we scan, or we impress, and we send some sort of a bite registration. to the lab. Why is it that the lab do not have on their articulator what we see in the mouth, and therefore when they make the crown, we fit it.

It’s either in supra occlusion or infra occlusion, what is challenging about the lab processes, which decreases the accuracy and henceforth, a technique like what we’re going to describe is actually useful.

[Tom]
Well, if you imagine. That you’ve got a set of models with a free end saddle. Very often when you try and hand articulate them, I mean, we’re talking about a normal occlusion here. We’re not talking about an anterior occlusion. Sometimes when you put the models together by hand, you find that they wobble. They don’t actually sit correctly. And unless you get a bike, wax bite block made and you mount the models with the aid of back.

Wax bite block, you can never be sure that you’ve actually articulated the models correctly. Now that’s working in analog. When you’re working digitally, of course, you’re trying to catch the occlusion with your scanning. And one of the issues about scanning is that there was a wonderful Keeley up in Leeds, who I saw presenting a small half hour presentation on errors in scanning.

And he was showing that there’s a tremendous error in cross arch scanning. I believe that a lot of that has been resolved in the very new scanners now. But at the time that we’re talking about, there was a tremendous issue. And effectively, it was as if the models warped about, and that was where the error was coming in.

So you couldn’t scan what you could achieve by working in analog. So, that was the challenge that we had. I’m not sure-

[Jaz]
If I’ll just add to that, Tom, in my experience, actually, is I work with a great technician, his name is Graham, and the odd case, especially when there are a lack of those anterior contacts, you have the difficulty or sometimes you have a really, really deep overbite, so deep that actually the anteriors sort of slip past each other.

Even that can rock in a different way and that can be tricky as well. But the technician, the reason I started to tell Graham what the shim holds were is because if I didn’t tell him the shim holds and he went by what the data he received from the iTero scan or in the scan, the occlusions often didn’t match up.

And it’s only when I started telling him, okay, there are in the occlusion that I’ve captured, there are shim holds, upright seven, upright six, upright three, upper left four, for example, and shim holds. And then when he actually is viewing it in his lab software, he’ll find that actually what he’s seeing in front of him on the screen is not what I have told him in my description.

And so what then he is able to do is manipulate it so that he achieves on the digital articulator what my reference values. And that has been very, very useful. But he tells me all the time that with digital, it’s not quite there yet. And you do get funny occlusions.

And actually, if you go back to your old cases, those who are scanning and just have a close study of the occlusion, you’ll find that actually there are instances where when you get finding reclusions that is not representative of what we have in the mouth. So therefore, for single unit cases, and I’ll ask you, Tom, in terms of technique, we’re going to describe about how many units can you use?

How many units can you restore using this technique? So before we even get to that, is it perhaps a good time to describe the protocol for using the functionally generated path technique?

[Tom]
Yeah, I’ll just pick you up on one thing. I was talking about ordinary models that you could articulate in your hand when you come to an anterior open bite or a class three or a severe class two, even by hand it’s difficult to get these patients models together. So scanning is even more difficult, but when you scan, so if your technician adjusts the way that the models meet on his screen, of course, that’s the static. What it doesn’t give you is the dynamic excursions that these patients make off their back teeth, not their front teeth, because they don’t touch. And those-

[Jaz]
It gives a good guess. And these algorithms and softwares, it gives a good guess. And it does have this sort of a part of the software, which it generates, and it relies on the wear facets existing on the teeth. But yeah, it’s a guess. It’s still an algorithm. And it’s just like semi adjustable articulators in these funky occlusions, it’s not going to be representative of the mouth or the TMJ.

[Tom]
No, and what I found most frustrating is when things don’t fit, and I think patients have a funny perception that they expect something to be perfect when you come to fit it. And if you spend an hour and a half adjusting it, I think it’s the patient starts doubting whether you know what you’re doing.

And so what I was looking for by falling back on the technique was predictability. And that was where this technique, I revived it, I suppose, and translated it into today’s dentistry. So it’s pertinent, both analog and to digital. The technique’s exactly the same. It’s just how you produce the final restorations. It’s different.

[Jaz]
So let’s talk about a patient with an anterior open bite and the only tooth on the left side they’re contacting on is maybe a premolar and a molar. And it’s the molar that has unfortunately got a crack, for example, and we need to give this tooth an indirect restoration. Can you describe how to use this technique in that kind of a scenario?

[Tom]
So obviously you’ve extracted the tooth. Hopefully there’s been enough bone to place an implant. And the first step would be to have your abutment, usually probably be milled titanium, not zirconia. At the back of the mouth, you don’t want to run the risk of a zirconia abutment fracturing. So it’d be obviously in titanium.

And you would have your occlusal clearance. So that would be the first step. And if you’re working digitally, the technician can have printed like a tiny little hat. In whatever material he uses, some people use hybrid composite, some people can do it in acrylic, you can have it printed, so it fits accurately onto your abutment that’s been milled, but really accurately.

If you’re working in analog, you can get your technician to just make the same hat using Duralay, he just does it manually. And when you can’t get the patient back, you sit them down, you take out the healing abutment, you place the new titanium abutment in place, and then you place your little hat onto the abutment, you obviously have to make sure the hat is not touching the adjacent tooth and stopping it from sitting, make sure it’s a very passive fit.

And what you have to have is clearance. Not just an intercuspal, but an excursive movement, so that you do not touch that hat. That hat should be completely out of occlusion. That’s the first step. Hopefully that’s quite clear. Jaz, is that okay?

[Jaz]
Yeah, so the hat is like a receiving platform on which you’re going to build in the anatomy.

[Tom]
Yeah. And then all you need is something like Duralay, GC do a wonderful material called, oh, how I pattern resin, which I really like it. I think its properties are marginally better. And all you do is mix it. Maybe ideally you get the patient to practice excursive movements. So I don’t know, some of my patients think sometimes I feel they’re dyslexic.

You say, move your bottom teeth forwards and they move their head and you go, can you move your bottom teeth to the left and they move their head. So you want to get the patient to practice excursive movements. And a bit like a pestle and mortar, just get them to move around, round, round, tap up and down and then you just mix the resin.

You place it all over the occlusal table, you get the patient to close and then start grinding around in all their excursive movements. Maybe an idea to put a little bit of Vaseline on the opposing tooth because the actual acrylic can sometimes stick to the opposing tooth, so put some Vaseline on. And you keep getting the patient to keep moving, moving them around, tap, tap, tap.

Whatever movements and excursive movements they can make, get them to do it until it sets. And that is the functionally generative. What it means is that the occlusal table is generated by the patient functionally shaping that occlusal surface.

[Jaz]
It’s not just the opposing anatomy. It’s the functional element of it comes by the movement.

[Tom]
So yeah and you can, once it’s set there’ll be sort of like flanges where they’ve pushed the acrylic aside, you can trim that, not the occlusal surface, but the kind of wings you can trim them away.

Yeah, any excess, but not the occlusal table that that occlusal table mustn’t change shape at all. And then you can put it back in the mouth and you can check and test. You say to the patient, how does that feel? Yeah, I can get my teeth. You can tapping together. That’s fine. You can check the shim stock, check your holds, and then you can get the patient to slide around with it in place.

And they should feel a complete freedom. They will be used to their own particular, and each patient’s different in these malocclusions where you have posterior guidance. They’ll just be able to slide and you say, is that comfortable? They go, yeah. Anything catching? No. And that is basically then the basis of producing the final restoration without having to make anything other than minor adjustments.

[Jaz]
Amazing. So it’s capturing the function and sending this little Duralay custom function generated piece of Duralay back to the lab to recreate. Now, just some nuances of actual, the technique acrylic gets hot as it sets.

It’s never gets so hot to the point to remove it or practice with acrylic when I make a temporary crown out of acrylic to sort of get the path of insertion so it doesn’t lock in. Insert, remove, insert, remove. Is that necessary? And also, does the temperature ever been a problem on a single unit for a patient?

[Tom]
No. Basically, no. Obviously, if you’re doing implants, it’s not pertinent at all. It is pertinent in, if you’re using it on vital teeth, but I’ve generally, I try really hard in these cases not to give the patient a local anesthetic because I find that if you give the patient a local anesthetic and then say tap up and down and slide around, they’re a bit disorientated.

And I’ve never had a patient suddenly go, Oh, it’s getting all hot. It’s getting all hot. Without a local anesthetic. So I don’t think that’s an issue. Certainly not with the GC pattern resin that I use. And yes, you’re correct. It can flow into proximally. That’s why you have to take the hat off, trim it a bit, but not destroy your contact point and make sure it fits correctly up and down and it fits with the patient’s occlusion.

You don’t just do it and then send it off. You just have to make sure that you check the contact points, make sure it seats correctly and make sure that the patient goes, yeah, that’s fine. That’s really comfortable.

[Jaz]
Could you then check this on the model, as well to make sure it sits on nicely, or is that usually not possible?

[Tom]
Yeah. I mean, it’s again, you see, if you’re working digitally, you can now scan that little hat that you’ve generated and just scan it and send it. That’s your occlusal surface. And you can just send it to your technician. If you’re working in analog, you obviously have to send the abutment back and you have to send the hat back.

Whether they’re working in an analog or digital, obviously they have to do the buccal lingual contours. They have to fill those in, but they mustn’t touch the occlusal surface. They have to work around it. They can subtract the edges. but not reshape anything of the actual occlusal surface. Cause that’s the temptation they go.

It doesn’t really look very nice, but if you ever look at these cases, they’re opposing cusps are incredibly very flat. So what we’re going to produce is also going to be flat. It’s not an entry into competition for the most beautiful molar of the year competition. It’s something which has to fit in to the pattern of the opposing tooth and the excursive movements that the patient makes.

[Jaz]
Yeah, there’s no digital library in the world that will have that information or give you that information. This is exactly how it has to be generated by the patient. I was telling you before we hit the record button, I’ve actually been using this kind of technique without knowing what it was called, but on teeth.

I don’t do implants. So sometimes when I have tooth with a huge cusp fracture and I want to try and minimize how much adjustment I need to do, but also try and get this new onlay, for example, in the molar, harmonious with the inclusion as possible, where perhaps we’re missing a number of teeth and we’re trying to give us more clues to technician.

I will get some expired composite out. I will dry the tooth in question, let’s say a lower left molar with their broken cusps. I will squirt some of this expired composite on, just manipulate my fingers around the tooth itself and get the patient to chew, chew, chew, grind, grind, grind, and then just cure it.

And then I’ll make that my pre prep scan. So when I’ve scanned that, that scan and the prep scan both make their way to the technician digitally. And I tell the technician to biocopy or copy the features or here’s some clues for you to make sure we get the bite right. Oh, by the way, here are the shim holes.

And I found that that’s worked really well for me and my technician. So you can actually use this on teeth as well when you want to do a digital technique. I mean, I guess you can even take an impression of that. And send it to lab if you wanted to maybe a triple tray impression and capture that as additional information to lab. Any thoughts or nuances on using it on teeth?

[Tom]
Well, I mean, I think you’ve sort of, the beauty of dentistry is that, if you’re good at what you do, you make your own, you can work out a solution to the problem. You’ve worked it out by using composite. You’ve effectively reinvented the technique without knowing it.

The only comment I would make about using composite is particularly if you’re working in analog. What you have to be really sure is that what you’ve cured in the mouth fits correctly on the cast model of the tooth. Cause that’s sometimes not the case. And then when your restoration comes back, it’s not.

So that’s why in terms of working with a patient digitally, that’s less than an issue to bring them back. But sometimes my way, you have to bring the patient back once additionally, you’re bypassing that. But I think there’s fractionally more room for error in that your little composite hat doesn’t fit the model as well as my Duralay which was made on the model. It’s a slight, slightly different.

[Jaz]
Yeah, I’ve never actually do it on models actually. I’ve always done it digitally, but I think as many of us are going digital, just something out there for people to remember from our chat today about this technique and that they can probably use it.

If they’ve got a scanner, it’s particularly lend itself to a pre prep scan. So the pre prep scan. And instead of what we might be doing is scanning the broken cusp just literally spend two minutes filling it with composite and generate the patient’s functional and parafunctional pathways and then give that information.

It’s gonna be more valuable than the technician seeing these broken cusps in the pre prep scan. There’s no value of that, but then you’re really building the value by adding that extra information in.

[Tom]
Yeah. I mean, anything that limits the time that you have to spend adjusting your restoration. I mean, particularly zirconia. I mean, if there’s one thing that I hate in life is adjusting zirconia, other than tiny little adjustments. So, if it’s really wrong, you just feel like saying, I’ll start again. It will be quicker. I think the point about this technique, whether we go the way that you’ve gone away, the way that I’ve gone slightly different.

But it’s the same, it’s different ways of getting to the same end product, which is minimal adjustment. And then this time and stress that you save by having something predictable is more, more than worth the effort you put into doing it this way.

[Jaz]
Excellent. Well, you’ve answered all the questions I had, Tom, about this technique. Is there anything else that you wanted to share about for dentists who are listening and watching this? So that when they start to use it in practice, any other nuances, or does that summarize it? Well, obviously I’ll point out the two papers that you’ve written. So when I email everyone and put the show links, I’ll add your two papers where they can access your webinars and contact.

But just as a the final bits, I mean, one thing I didn’t ask you actually, is what is the difference between what we’re doing here? And what we call a custom incisal guidance table? And why not just use that? A dentist might say, Hey, why don’t you just use a custom incisal guidance table here and let the lab do all the work. But I think we’ve kind of answered that already, but just to give that clarity.

[Tom]
Semi adjustable. I mean, nobody’s in this day and age is going to buy 25, 000 pounds of fully adjustable articulator. I’ve never, I’ve seen one, but I never used it. I believe it takes the better part of half a day to set it all up and get all the readings so we can forget about that.

The thing about a semi adjustable articulator, yes, you have your face bow and you can take your lateral excursions, but when you don’t have any anterior guidance, I think the guidance table is there to reproduce the anterior guidance when you’re restoring anterior teeth. That’s mainly when it’s used for.

I don’t think that the movements you can make with the articulator with the back teeth providing you guidance gives you an accurate incisal guidance table. I don’t think it can do that. I think the patients are capable.

[Jaz]
I agree, because it’s relying too much on the posterior determinants, I guess.

[Tom]
Yeah. And articulate, semi adjustable articulators only have a certain degree of accuracy. I mean, I haven’t used ModJaw, I know it’s very expensive, but I think what’s interesting even about ModJaw is that if you’re trying to articulate models for some open vertical dimension to the best of my understanding, there isn’t actually a face bow that goes with ModJaw.

You actually have to scan with your occlusion already open. And that’s how they do it to get the degree of accuracy that they want. The other thing that you mentioned, is there anything else that I’d want to say? I’d want to say is we’ve talked about one unit. Let’s say that we’ve now got the lower right 5, 6, 7, 8 missing and you’ve placed two implants.

Well, of course you can’t do your technique of using some old composite because there’s nothing to put it on. It’s fresh air. And so that’s where I have a little jig made up, which I screw into place. The patient comes back, take off the heating abutments. I put the jig into place and do exactly the same thing with the Duralay, the patient, taps up and down.

I mean, that can be in a normal occlusion as well. Patient taps up and down, slides around, they generate the path, and you send that off to the technician. You let them finish it off however they want to, reshape it, and then they scan it and give you the restoration. And I’ve not had any major issues with the occlusion doing that.

And I think that those free end saddles can sometimes be very hit and miss if you’re working digitally. I mean, if it works well, it works well, but if it goes wrong, it tends to be drastically wrong and you have to start again, and there’s no guarantee that you won’t reproduce the same errors. Whereas this technique that I’m advocating is pretty foolproof. I mean, it gives you something which really doesn’t need much adjustment at all.

[Jaz]
What’s the limit you think? I mean, if you were doing a quadrant, which makes sense, and you’re borrowing some information from the other side based on how the patient generates those movements. How far can we go with this?

I mean, I guess, could you go cross arch, I suppose a single unit on one side and then a double unit on the left side. At what point do you think, okay, we need to change techniques here because it’s getting too big of a case?

[Tom]
I think it is in those funny cases we discussed with the class three, the anterior open bite, the third one, the one that I forgot to mention this, I don’t know how many of you realize that patients go, it can go into protrusive where they go into initial incisal guidance, but they can then bring their lower teeth further forwards and they go from anterior to posterior guidance.

Again, terribly difficult to reproduce on an articulator. So, I think it’s where you just have difficult occlusions or you’re not really sure. I think in an ordinary, let’s say it’s even bilateral free end saddles, your guidance in a normal case would be coming off the anterior teeth. So really all you’re worried about is your intercuspal registration to be correct, because the rest of it’s fairly easy for the technician.

It’s where you don’t have anterior guidance. I think that’s the one that it’s easier in the long run. For both you and the patient to do it predictably using this technique. I just think it’s not necessarily quicker, but you have less issues and who pays for it if you have to remake it because it’s completely wrong.

[Jaz]
Well, it gives your technician extra information and it increases the chance of you getting it right the first time and it’s a nice clever little way. So thanks for resurfacing that technique for us. Like I said, it’s an age old thing, but it’s nice to see it again in a new light. And I think the implant dentist will really appreciate this for these funny occlusions and even the general dentist, the odd of a funny occlusion, or just giving extra information to the technician, whether you use this acrylic approach or if you’re digital, you want to use a composite.

I think it’s been good. I’m definitely gonna reach out to you again for more occlusion topics. I think there’s so much we can learn from you with your experience and wisdom. And so yeah, I’ll definitely be emailing you for that. I’m going to point everyone to your resources, which I’m very excited about. Any last words, Tom?

[Tom]
Yeah. I mean, I think, if things work for you, why change them? I think, one of the things about modern dentistry, Instagram dentistry, I do a lot of teaching of sort of recently graduated dentists and they keep reading things on Instagram and try and put those new techniques, whereas actually they haven’t mastered the basics.

And so they tend to lose their way. But I think this is something that’s a bit more specific. It gives you a much better result and it’s not something you have to change. It’s just another string to your bow. And it’s just worth considering, if you’re not sure, you think, oh, this might be a bit difficult. That I think is when you use this, but I think, for everyday general dentistry, I don’t think this technique applies at all.

[Jaz]
And it’s always good to pick up the phone to your technician and just ask, how is everything going with my last 15 crowns in terms of occlusion and give feedback. Like when the crown I get back is shy from the lab, Graham will know about it. When I’ve had to do a bit of adjustment, Graham will know about it.

And when it’s everything’s just perfect. I’ll be sure to tell him as well, because it’s really sad if all technicians hear from you is the bad news, when they’ve done a great job and everything just fit together well, I do let my technician know as well.

I think the lesson there is communicate. A lot of people don’t know the name of the technician or who’s making it. Maybe find, if you use a big lab, identify one person and build a relationship with them would be great for your restorative dentistry.

[Tom]
Yeah, I mean, I had my own two, well, sorry, I had two of my own technicians, one retired and then the second one took over, but I only had two technicians in 40 years and we learned to work together and he would instinctively know, feel if there was something wrong and he would communicate that to me and go, listen, do you think you could re register the occlusion or something?

I think the shame, not the shame, I mean, big commercial laboratories have to exist, but the shame about the big laboratories is the work gets allocated, it’s terribly difficult to work to build up a relationship with the technician and always be assured that he’s the one that’s going to be the work, do the work you can ask. And it’s definitely something that I think is really worth doing is having a relationship, but that’s not always possible.

[Jaz]
I think step one would be for young dentist to visit their even if it’s a big lab, visit the lab and identify a familiar name on the lab sheet. Now, I’ve noticed that this person has made a few good crowns and go and speak to them, introduce them, show your face, be like, Hey, is it okay if I ask for you to do my lab work and we can work together and exchange photos?

And you know what? That technician who is doing work never gets feedback because they don’t know exactly which dentist it is. Once they start seeing your work, a familiar face, they’ll give you that extra care and attention and is great nowadays with WhatsApp communication. I mean, async communication via WhatsApp.

Graham will just make a video or voice note me some concerns about the occlusion or whatever. And it’s great for me to, in my own time, once a kid’s asleep and just voice note him back. And so it’s great to have WhatsApp relationship with your technician as well.

[Tom]
Yeah, absolutely. 100%.

[Jaz]
Amazing. Tom, thanks so much for your time and we’ll definitely welcome you back again.

[Tom]
I hope you enjoyed it. Whoever was tuned in today. Thanks very much for listening.

Jaz’s Outro:
Thanks so much, guys. Well, there we have it, guys. The functionally generated path technique. Thanks so much to Dr. Tom Bereznicki for sharing his wisdom.

I’m definitely going to bring him back to talk more about occlusion. Now that you’ve made it all the way to the end of this episode, why don’t you answer a few questions on the app, whether it’s on protrusive.app website and you have a subscription there, you can answer a few questions to get CPD for this episode.

Or on the native iOS or Android app. And on both these, the login also gets you the premium notes as a PDF and the transcript and a whole bunch of cases and clinical recordings that I produce. All cheaper than a Nando’s per month, which is tax deductible. All of those with subscriptions, I really appreciate that you are supporting this podcast so that I can have a team and keep this podcast running.

So I want to thank the team that’s Erika, who’s our producer, Mari, who does all the CPD certificates, and this episode’s premium notes was done by Krissel, who has returned to work to Protrusive after taking a year out. So welcome back, Krissel to the team. Oh, and one last thing before we say goodbye.

If you know someone who hasn’t heard of Protrusive and you’d like this episode or some of the previous episodes and you want to send it to them, I really appreciate that. That’s how the podcast grows and we’re able to get more and interesting guests on from all over the world. Thank you so much once again.

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

Hosted by
Jaz Gulati

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