Posterior Guided Occlusion Part 1 – PDP031

Jaz’s Introduction: Hello, Ron and welcome to another episode of Protrusive Dental podcast, a very special episode, something very different. Do you believe in canine guidance? It’s the first thing that we’re taught at dental school is the only thing that you remember about the occlusion aspect of dental school. Whereas having been to many occlusion courses, and then championing the role of canine guidance, I did always think why is it that some of my AOB patients are just fine? Why is it that some of your patients in fact, most of your patients, according to some studies, do not have canine guidance? And why is that okay? I think we’ve covered it a little bit in some of the episodes with Barry Glassman before, but I want to bring something completely different to the table. So today, I’m joined by Dr. Andy Toy, who is a fantastic dentist and mentor, based in Nottingham. He is an educator for Invisalign, and he treats TMD, does orthodontics and he has a massive interest in occlusion, hence why I connected with him. The story about Andy and you’ll hear his story throughout is very fascinating how he did all the traditional routes of occlusion was also in favor of the traditional mainstream sort of knowledge about canine guidance, and then how he met some people, and how he also considered that they may be another way to think about occlusion, that might be another theory that we should consider. And that theory is the PGO, which is posterior guided occlusion. So imagine everything you know about occlusion, and turning upside down. And then thinking, whoa, I mean, this blew my mind when I first came across it. So I want that as part of the handout of this episode, I’m gonna leave Andy’s ebook about PGO for you to read, because it’s a two part episode. Part one, this one is more of the introduction how Andy had done all the other occlusion bits and bobs, and then learn about PGO, and then we talk a lot, we get a little bit deep into the PGO and I leave you in a bit of a cliffhanger. Sorry, not sorry. And next episode, we’re going to get into how to actually apply PGO concepts, not patients, and how to actually make it practical. The Protrusive Dental Pearl I have for you is a communication one, what about when you get a patient and maybe you’ve seen this patient a few times before. And their oral hygiene is just not up to scratch, they still have plaque at the ginger margins, and you’re not 100% happy? How did you communicate your patient? Sometimes it’s embarrassing to as a dentist to say to a patient, I look you know, you’re not doing a good job, especially when you know, they come in, you have a nice chat with someone you’ve been seeing for quite a while. And then to put like a negative twist on the appointment and say, Look, I’m not happy with your oral hygiene, which we have a responsibility as clinicians to do. So I think there’s a tactful way to communicate that to a patient actually, you need to do a little bit better in a you know, keeping politeness and kindness and sincerity at the core of it. So my Protrusive Dental Pearl is that if you want to tell a patient that they need to improve something about their oral hygiene, here’s what I like to do. I like to ask their permission, and it works every time. So I say to a patient, may I kindly have your permission to give you some feedback about how your cleaning is going? Or May I kindly have your permission to give you some feedback about how your brushing techniques are going? And always like Yeah, yeah, fine. Yeah, please tell me I’m really interested. And then you show them in the mirror that look, you’re here, here, here, you’re doing amazing. Please keep this up. I’m really, really happy with this. But can you see around the lower anterior as you move the lip out of the way, and then you see all that mature plaque that they were missing for probably weeks and months. And then you show them look with a probe and you lift off the plaque. And I’m just concerned that you’re missing this plaque. And you probably haven’t realized it’s probably because of the fact that it’s so low down, your toothbrush just not reaching and just want a small change in technique, we can get your gum hygiene from 7 out of 10 to 10 out of 10. And they are so so appreciative of having advice given to them in this way. And it’s much better than saying look, your general dental checkup today was fine, but you need to do better with your tooth brushing. It’s not only more specific, but the fact that before giving them criticism, you allow them to give you permission. I think that’s really powerful. So let me know what you think about that. Anyway, I’m not gonna take any more time let’s join the episode with Andy Toy on posterior guided occlusion part one.

Main Interview:

[Andy]
Hello.

[Jaz]
Hello Andy. How you doing?

[Andy]
Very well. Thanks, Jaz. Nice to see you.

[Jaz]
You too. It’s great to finally meet face to face have been talking on the phone and emailing on the run up to this podcast. So it’s great to finally have you on, on the Protrusive Dental podcast.

[Andy]
It’s a real pleasure. I’m so looking forward to our conversation.

[Jaz]
I am too because one of the things that I want to do with this podcast is I want to make it a voice for all I mean, I don’t want this podcast to be is a reflection of just my beliefs and mainstream beliefs because what I want to do is listen to other alternative options because I think that’s how we can expose ourselves to new treatments, advancements in the long run. So I first heard about you when my friend, the [Mitlani] brothers, were doing a study day a couple hours evening session, and it was posterior guided occlusion and that’s when you came my radar. We’ll talk about that today by also understand you you teach on the clear aligner diploma?

[Andy]
I do. Yeah. Yeah, that’s most of my work nowadays.

[Jaz]
Brilliant. And so tell us how you’re sort of career has evolved into this, you know, occlusion, clear aligners, orthodontics, and just tell the listeners where you work and a bit about yourself.

[Andy]
So I qualified way back in 1980, in Bristol, when the world was black and white, and felt a lot simpler. And I was very lucky because I had three years of undergraduate training in orthodontics, so we saw patients all the way through. And so as soon as I got into general practice, orthodontics was part of my life, and it was all removables, functionals and stuff like that. I was really, really lucky with my first job, because I effectively had vocational training before it existed. And my boss [Bob Barrow] was always interested in extending his knowledge and applying it in practice, he was a really strong general practitioner, and willing to go out on a limb. So it was a friend of his actually was a perio consultant in Sheffield. He has me sort of hanging onto the tables of [Bob Barrow] at 22. And you can see I was really into my dentistry and just like you, and he said, You ought to find out about occlusion because we’re starting to think about occlusion and restorative dentistry and stuff. I said, Yeah, that sounds good. He says you need to go to the Pankey Institute. Right? So there I am, 1981 is mentioned this thing called [Pankey Institute]. Now there’s no internet in those days. But he says

[Jaz]
[inausdible] in this world.

[Andy]
Right. Well, exactly. So anyway, I write to the Pankey Institute, and I met a couple of dentists who are in his sort of friendship groups as well. And they were very encouraging, just like you would be with a young dentist. So I stole up there in 1982 in November, going there to learn about occlusion. Okay? I sit there. And the first morning, you sit in a big sort of circle. And you tell people while you’re there, and I’m the youngest by far. So over half the dentists were ancient as far as I was concerned, which meant that over 35, right? I’m here to pick up on Dr. Pankey’s philosophy and all that sort of stuff. I wonder what the hell is all about. Anyway, Pankey is alive at the time. So he comes in about 11 o’clock in the morning on a Monday and he starts to talk about, you know, why the institute is there and he is put some of his personal stories. And by the Wednesday, the penny drops, you know, this is there’s more to dentistry than just occlusion. You’ve got to look at the patient as a whole in a comprehensive way. Not just teeth and gums and jaws, but you know, the emotions, this personality types, but also then it’s all about your life in dentistry. So this really, really helped me at the time and I got me very, very excited. So I’m really getting into occlusion and I go on all of the occlusion courses I can go on. So I don’t know if you ever heard of Roy Hickson.

[Jaz]
Yes, of course.

[Andy]
Yes. So Roy set at the British society of cultural studies. And I went on Roy’s very first course that he set up and it was actually he set one up. And he brought Jim Moore over from the Pankey Institute because Roy had done all the Pankey stuff. And I went on that I went on [Harold Gal, Brendan Stack]. I started to do courses with osteopaths and chiropractors, cranial osteopathy, you know, I learned how to tune into the cranial OCR, cranial sacral system. I mean, the world we got into nutrition, you know, the world just opened up and you’re willing to have a look at anything and try it. So I made TMD part of my practice in life as well. I mean, you need a certain approach to TMD to be a certain type of practitioner but because I’ve done a lot on the sort of personality and people side of dentistry it really tuned in with that. And that carried on and I can I was part of the BSOS and you know, we went on courses with them. I remember very well still actually, Henry Tanner coming to Warwick that the early 90s and we had three days with Henry Tanner, for instance, we were going into trigger points and all that stuff. Anyway, that’s party life, occlusions party life. And in terms of orthodontics, I started the straight wire ortho in the 90s. I did the University of Sheffield course up there, and started doing more and more also. And so that was part of my general practice life as well enjoyed it. I’m pretty useless with my hands to be honest. So, I don’t know if you know [name]. But [Milesh] became a part with me in Loughborough where my practice is. And he’s so good with dentistry, you know, I pass all the blood stuff to him. And he was doing all the crown preps and stuff like that, but I was more the ortho and the TMD. And

[Jaz]
It’s interesting, Andy, you say that because I always am. I did have this once upon a time a belief that if you don’t like dentistry do ortho.

[Andy]
Okay. Well,

[Jaz]
I’ve since moved on from that I definitely.

[Andy]
In a way. So, I mean, you learn to do the things you love. Right? And you know, and if you can manage your practice that way, and that’s one of the benefits of I’m doing right. Anyway. So another thing that was in my life was I got heavily involved with the faculty. And I was doing a lot of teaching a with foundation dentists and things like that. And in the 90s, about the mid to late 90s, this thing about evidence based dentistry comes into the world, right? So I’m what I was a really, really strongly in favor of really good general practitioners, especially so great, you know, and the academics are great, we’ve all got our part to play. But I feel very, very strongly that the general dental practitioner is really the top of the tree, to be honest, rather than the bottom of the barrel, like they’re often thought, by specialists and not everyone. So anyway, in part, the faculty, were getting involved with teaching and research and evidence based dentistry comes out and all these academics are producing these research. And I’m looking at the results. I’m thinking, well, that just doesn’t look right to me. That doesn’t apply to the population I’m seeing in the Loughborough. So I’m getting a bit pissed off, to be honest,

[Andy]
can I say that ?

[Jaz]
Oh, you can’t. You certainly can’t.

[Andy]
I just stop. So anyway,

[Andy]
because these academics are telling me what it should be like, and it’s not like this, right? So I decided to get into some practice based research, there was a whole sort of, you know, movement and to do research is based in practice. And I started getting involved with that. And I’m part of the local NHS network and the deanery, and all that stuff. And one of the things I do is I decided to go on the Oxford University evidence based dentistry course, that was run by [Derek Richards]. So you might know him because he was the editor until recently of evidence based dentistry as part of the [inasudible] So Derek, lovely guy, he’s from Wales, and the valleys as it happens. So we know, we started to do that. And that’s nonsense. And I was beginning to learn about what is the nature of evidence, Okay? Another thing that happened in my life is I taken a master’s in clinical education. So clinical education involves a lot of social science research, okay, and evidence. And I started teaching the social science research module on that course. So I’m now teaching clinicians and nurses and all dentists and stuff like that all about social science research. So I’m getting heavily into what do we mean by evidence? And understanding that actually, scientific evidence is just one type of evidence. And whilst you and I might have been brought up to think this is the truth is really you start to appreciate Well, actually, evidence has different levels of quality and applicability. And actually, no matter how much evidence you’ve got, nobody’s got the evidence for the patient in front of you.

[Jaz]
100%.

[Andy]
So you have to understand the limitations of the evidence as well. So all this was part of my life. And but I’m also into occlusion right? So there was a BSOS trip to the University of Florida. I think it was 2002 or 2003. And we went to the Parker E Mahan Facial Pain Center, University of Florida, Gainesville. Henry Gremillion was the lead director there. Parker Mahan was still alive. And Parker Mahan taught me TMJ in the Pankey Institute in 1983, I mean, he was a fantastic personality. He brought anatomy alive for me, you know, in a functional sense. They used to, they got me there three days so that they’d have to build you up for two days. So you’re ready to train. Right? and Parker Mahan comes in. So Parker Mahan is obviously donated a lot of money to University of Florida who set up this facial pain Center, where there was 12 of us from the UK And we go have five days at with Henry Gremillion, CM patients, do an exercise and stuff like that halfway through the week, and Henry comes up to us, he said, we’ve got a colleague of ours was visiting Parker, his mentor is a guy called Ron presswood. And he really likes the Brits. He goes off to the UK a lot. And but and he’s got a particular way of looking at occlusion. Are you interested in listening to Ron? So we all say yes to and what else to do. So it’s take us in this little lecture theatre. And there, Ron turns up at two o’clock. And Ron is this quiet, introverted Texan, who speaks very quietly almost speaks out the side of his mouth, sometimes, you know, and you have to sort of really stop and listen, he’s introverted. He’s an ultimate like biomechanical engineer. And he can go off at tangents, and stuff like that. And anyway, he starts to give us his presentation on his views on occlusion, which is the posterior guided occlusion. And I’m sitting there listening, and I’m, I can’t don’t quite understand what he’s talking about. But he had serious evidence. Because all the way through that week, I’m telling these and were talking to these dentists, I’m saying, you know, what goes, there’s no evidence for this stuff that we’re doing really, if you get down any sort of textbook like Dawson, right? Sitting up there, you go to the end of the chapter, masses of references. And I had learned to look at those references in. Well, you know, they worth nothing. So we change in the 80s, from volume quanty of evidence to in the 90s and early 2000s. It’s about the quality of the evidence, and the quality, the evidence for occlusion was very, very poor. Okay? I knew that stuff worked. But the way that I’ve been taught at Pankey, and all these other places and modified it to my own thing, but so I wasn’t wrong. occlusion was important. But the evidence was poor. So Ron is done. And he’s coming up with some serious evidence, such as anthropological studies, okay. And the other thing about Ron was that he’d been one of the original teachers at the pankey Institute. So when they set it up, I think there was 12, or 13, original teachers, and Ron had been a teacher there, right from the start. He then taught with Henry Tanner for 20 years. /-Wow./ So I didn’t know what he was getting. It was very challenging what he was telling me because it’s feel that felt like it was like 180 degrees from what I was being taught and practicing. But he had evidence and I thought, I’ve got to listen to this guy, I’ve got to get to understand it. Now, the one of the reasons is challenging, is we’re all sitting there, we spent thousands of pounds to get there. We’re all going BSOS, we’ve spent tens of thousands of pounds learning about occlusion and I will tell you, right, and I bet you’re the same. And you will get embedded in one way of thinking and you almost have to enjoy, you have to say it right? Because you, you know you’ve

[Jaz]
committed

[Andy]
if you say it’s wrong, you feel a bit stupid to go on a site. You know, we all get this is one of the things about occlusion, I think we all get entrenched. And one of the lovely things that I’ve noticed about you is you’re willing to be what I call positively skeptical, right? You just don’t accept it, but you’re not going to ignore it either. That’s so anyway. And , that’s the stance that I would like to take. So Ron tells us this stuff. And I go up to him at the end, you know, and introduce myself because the Pankey guy and things like that. And I said, it’s really fascinating. I don’t really get it, but I really want to know more. And he says, Well, I’m coming over to the UK in three months time, why don’t you come to the study club. So we off down to Bristol for a study club, and listen to him again. You know, again, I get a bit more understanding. So I invited him up to our study club in Loughborough. So three or four months later, he comes over to the UK again, one of the reasons he has to come to the UK is he because he can’t talk about this stuff in the US. He gets shoved it down. A little text and guy right engineering type. And you know, there’s people with vested interests on teaching a certain type of occlusion approach to occlusion over there. And he was saying is not like that.

[Jaz]
Andy, for the benefit of those listening some of the young dentists out there who may be UK graduates for example, which is the majority of my listener base. I know Adam from America and those listening in the US right now please don’t be offended by what by what I’m about to say. But in the US just as you mentioned, Andy, it these conferences, they do get very heated with the different occlusal camps and say, and I’ve heard you know, of fist fights breaking out at events and stuff. So just to give some context of what Andy’s saying here is that, you know, that’s probably a good reason why Dr. Presswood was not able to speak about his very alternative view at the time.

[Andy]
Yeah, absolutely. So he, and you know, he wanted to explore this model. Right? One of the things I’m going to really enjoy about our time now is you’re gonna ask me some questions about it. And every time we talk about it, we learn something about it, because it needs to be tested. It’s just a theory. But I think it’s a better theory than all the ones I’ve seen before. So Ron comes over. And I’ve seen him a few times, I’m still not 100% Sure. Because he’s telling me that is not really about canine guidance, right? And I have worshiped at the altar of canine guidance for 20 years, okay? and tried to build it in and I can imagine, I can remember building massive bits on my splints to get the canines involved. Okay? You know, I’ve spent that time. And he’s telling me, it’s not like that. So I still don’t really you’ve got to get into your own clinical experience to really, really trust something. So one of the approaches that he taught me and this is the way that he and Henry used to teach the splint courses. He said, If you start to and this is a great tip, actually, for anybody doing TMD. Okay? Is you let the patient drive the adjustment. Right? So the patient, it’s not your splint, it’s the patient’s splint. So one of the things that you do is you put a splint in tap, tap, tap, rub, rub rub, he say, what does it feel like? Is anything that feels like is in the way and they point to a spot, they take the splint out. He’d point to it said, Is that what you mean? He says, Yeah. Can I adjust it? I’m gonna say yeah, so we adjusted, okay, so the patient driven splint adjustment,

[Jaz]
I love that

[Andy]
You will have in the back of your mind, I think I know what it should look like at the end, right? But you let the patient drive it. Now, when you let the patient drive splint adjustment. They don’t want canine guidance they don’t like. Okay? So I was starting to sort of pick that up. The other thing that happened is I had a patient, she was the daughter of a local dentist. And she’d had obviously, she’s a great big class two. So you can see this. And as a teenager, she did every fours taking on everything driven back. And she had a really deep, tight two div two. And she had a horrendous TMJ, head and neck pain, horrendous. And you can just imagine that the mother, you know how bad she felt because she’s a dentist. And she ought to be able to do something about this, and nobody could do anything about it. And she was one of my first patients I put on a PGO splint, right? And I’m telling the mother, let’s try it. Let’s have a patient driven splint adjustment experience. And so the mother is then sitting in the corner there. And we basically one of the things that you want to do is to get some what we call freedom in centric. I’m sure you’re familiar with that. And I was basically building and building and building and building the vertical here and getting that release. Okay, of those that deep bite. And I basically said, Well, we kept driving it she said kept saying I don’t like this at the front. I kept taking it off. And I had the her actual teeth poking, just poking through the anterior section,

[Jaz]
I could all rise up, right.

[Andy]
And we sent her away. And it makes an incredible difference. And so I basically just put put, it felt a little bit like the old gelb splint, I don’t know,

[Jaz]
I was just going to say that it seems like a almost like a posterior like a pivot appliance almost appliance, you know, what you were describing there.

[Andy]
It does vary but it’s more because I’ve done loads of them. But actually the working part of the splint is what we call a Centrum at the back of the splint and then fill that in. So it wasn’t just a flat plane, or a gelb appliance was designed to move the condyle into this some sort of special position and stuff like there wasn’t that. And I did cover the anterior teeth. But there was some little windows there for the because I’ve grown so much away.

[Jaz]
Surely

[Andy]
Anyway, made a big difference to her head and neck facial pain. So the penny was really starting to drop here and I’m thinking Yeah, well, so all my splints then I started doing as PGO splints, and I got good results with my normal Tanner appliances to be honest, because the way they teach you the Tanner appliance at the Pankey, they teach you freedom in centric and make it very flat. And it’s just that they say you should have canine guidance and immediate posterior disclusion. So what I was doing here is was I was creating a Centrum at the back with no posterior disclusion but smooth and harmonious patient driven, because they’ll tell you if it doesn’t feel right. And I wasn’t bothered to put a ramp on the front unless the patient, you know, eventually got into it. And I was getting good results with pain, just like I was getting with my tanner appliances. But interestingly, a lot of the clicks started to clear up as well. Because I used to say to the patient, I think I can make a difference to your pain, but I’m not too sure about the clicks. But if they if you’re out of pain, would that be okay? They say, yeah. And so that I was finding with the PGO splints that the clicks were starting to go. So that was an interesting experience. So

[Jaz]
In my map of the world, Andy, the way I can, because it’s funny, right? When you learn something, and then you apply it, and then you figure out supposedly away something works, and when someone else offers an opinion, and sometimes you can say, okay, maybe I was still getting good results, but it was for different reasons. And when I initially thought, which is why we had that phone conversation, you mentioned that and I really respect that I really like that. So in my map of the world in the moment, when you when you said exactly what you said, I’m thinking that by having these centrums, you’re giving the temporomandibular joint a bit more support, by you know, by having a bit more posterior guidance, if you like, rather than less support, for example, the more you anteriorise, a splint, the more seating you get other condyle, and that may be compressing some of the tissues I mean, that’s me being very logical engineering type.

[Andy]
Okay, so you’re right in terms of support. But you get you do want a seated condyle, Right? And so the reason that you get a more stable condylar position in function is because you’re switching muscles on. Now, this is a significant difference to every other approach that I’ve heard in dentistry, that, you know, you get health, when you switch muscles off, there’s something about the overworking of the muscles. So I’ll take you back now to my work with chiropractors and osteopaths. This is one of the sort of challenges I used to get. And I learned this particularly off osteopath, they were all about function. And it wasn’t, whilst they were in a structural way, what they’re really interested in is the patient’s function. So when we were looking at a patient, you start to see whether they’re not symmetrical, you know, is that a problem? So not really, because you can be functional in an asymmetric way, because nobody’s a symmetrical, okay? And so, and they would be always, when they’re talking about joints and stuff is that we want to make these muscles strong around the joint. And then, you know, I don’t know where you’ve had a knee injury or anything like that, you know, you go and get treatment for it. What do they want to do? They want to strengthen the muscles. And yet the jaw joint, they’re trying to switch muscles off what Ron was coming back with, he says, we’re actually no, we want stronger muscles. Healthy join needs good strong muscles, okay. And you can go to Wolf’s functional matrix, okay. And there’s a basic biomechanical principles that show that the structural part of the joint is dictated by the function. The better function you have the better the joint.

[Jaz]
Okay, that’s like a functional matrix theory as well. Right?

[Andy]
Wolf’s functional matrix. Yeah. So you got so. So when eventually a part of the story is then Ron keeps coming back over and Ron gets a one of his patients offers him to a quarter of a million dollars to do some research. Right? So Ron comes back over to Loughborough He says, I’ve got a quarter million dollars, you know, and I was telling you, I’m interested in practice based research. And always when we’re trying to do a research project. The money was always the problem. This time, we’ve got some money, right? So I’m thinking, right, we got some money. Now let’s do something with it. So I write to all of the dental schools. I know in the UK, I’ve got an interest in TMJ and occlusion. And instead of me saying our GDP, can I come and do some research? Let’s, you know, they say no, we I’m getting funding. I’m saying our GDP, can I come and do some research on I’ve got a quarter million dollars, [Jaz] a better position. [Andy] So anyway, send all those emails off. And guess how many replies I got? I think I sent eight emails.

[Jaz]
I mean, it’s probably going to be not very much unfortunately.

[Andy]
Zero. absolutely zero. So Ron comes back three months later, I say to Ron, we’ve done it we’ve done a whole study club, it’s four o’clock in the afternoon. And we everybody’s gone home and I said, Ron, I can’t spend this money is and I said it, the dentist just don’t get it. We need somebody who understands muscles and joints. And then the penny drops. I mean, Loughborough. Right? Literally a mile down the road is one of the World’s Leading Sports Science universities, the best. Okay. I think, hang on a minute, forget the dentists, best foot biomechanics? Because that’s really what we’re talking about. So, next day, I write email at this point, Ron and I had written an article, we got published in the, in the faculty journal. It was a historical perspective on occlusion and stuff, right? Because, and we brought in some of this anthropological stuff that Ron got involved with it. Right to the head of the department. And two weeks goes by, no response. Okay? So, you’re in practice, right? Do you know what it’s like, you get patients you get to know and there’s a particular patient Maria. She’d been a patient of mine for probably 15 years, her and her family. Maria was from Eastern Europe before the Iron Curtain came down. She was an Olympic Rower. And she basically defected when she was over on a competition in the UK, she got a knock on somebody’s door and said, I want to leave East Germany. Okay? And she’d come to live in the UK, she’d ended up as a research assistant at Loughborough University. Okay. She comes in to see me. And your 20 minute appointment is five minutes during the dentistry and 15 minutes talking about what’s going on. And she says to me, Well, what are you up to? I said, Maria, I just written to your head of department. Oh, because I’m interested. There’s research, I’ve got a quarter million dollars. Oh, what did he say? I said he hasn’t report replied. She says send it to me. Okay? Within two days, I got a response. The next week, he sent me to see this guy called Dr. Mark Payne, who’s like leading one of the research teams. Anyway, eventually, we get to do some proper biomechanics research at Loughborough University, or because of those connections that are out the luck that we had. And we spent,

[Jaz]
it’s amazing how these things work out with patients, sometimes.

[Andy]
It’s just amazing. So then with Ron, then we did some serious research at Loughborough for surface EMG muscle testing, and the effect of occlusion on the action of the muscles. And this is peer reviewed research. And we were working with three PhDs in Loughborough. And these guys, they don’t give a damn about occlusion, and whatever model of occlusion and whether you’re a Dawson guy or a Tanner guy, or Kois guy, or whatever it is,

[Jaz]
for the love of science,

[Andy]
they are, well, their job is to do top class science, otherwise, they don’t have a job. So these guys really know their biomechanics. And [Steph Forrester], she is actually no done more sEMG measurements on massseter and temporalis anybody else in the world. And it is, you know, it’s first class basically. And it was there to test the effects of different occlusal conditions on the action of the muscles of the head and neck. And actually, they found you can only really measure masseters and anterior temporalis. You can put stuff everywhere else, but you won’t get a decent measurement, they wouldn’t allow for that. In fact, this might be the time I don’t have time in the story where we I’ve got you know, I asked you to get those lollipop sticks.

[Jaz]
So my wife is a at the moment. So to put context, if you’re listening to this episode in the year 2021, or something, it’s locked down period COVID-19. And my wife, conveniently is a COVID swaber at the moment. After suffering from COVID herself. She’s now a COVID swaber. So she’s doing a great work for the NHS in the frontline. And she was able to get these wooden spatulas 72 hours before so that they can hopefully be COVID free by now. So I’ve got them ready.

[Andy]
Okay, so we could reproduce this is one of the things I do on the courses, we can reproduce a bit of the evidence. Okay,

[Jaz]
Let’s do it.

[Andy]
Is this a good time to do this?

[Jaz]
Yeah, let’s do it.

[Andy]
Okay, so basically, we looked at, I can show you the results as well if you want, but we looked at the six different occlusal conditions on healthy subjects, which I think is significant because we’re trying to define what is a healthy jaw joint and healthy jaw joint function. And when you know what health is, then you know how far they deviated from it and you know what you’re trying to aim for. And one of the problems with

[Jaz]
definition of health is I’m sure you did it, very mythologically properly range of motion. I mean, the whole law absence of it, it’s not it’s not just absent of symptoms. Did you take MRIs for example to confirm health?

[Andy]
No, they did it on, they use USA internationally accepted definition. And you know, the patient’s reported no pain, ability to chew and a good range of motion where it comes out where it was, what exactly is and all these guys are pretty well Loughborough Universitystudents, basically, a lot of them are triathletes, actually because [Steph Forrester] run the trade club. And they’re trying to keep him with her. So they get involved with research if she said so. And so you can do it with tongue blades, we actually used for the posterior ones, we used cotton rolls, actually, but these will do anyway, and what we did six different occlusal conditions, we did a clench. Okay, we did an anterior blade, parallel to the maxilla. With an anterior blade steep. So you probably heard of Lucid jigs?

[Jaz]
Absolutely, yeah.

[Andy]
So that’s effectively what a Lucia jig is, yeah, we did one blade occlusion on one side, occlusion on the other side, and then occlusion of posterior that is and posterior occlusion on both sides. Okay, and what you find is funny enough, in these healthy patients, when they clenched, without any blades, you had pretty good contraction, the masseter pretty good contraction of the anterior temporalis. And not only that, it should be coordinated as well, they spent a lot of time in those first few minutes seconds of contraction, and see whether it was coordinated, and there was a high level of coordination. Now we all know this, when you put the blade at the front, lot austie what they found was the temporalis shut off. Okay, the masseter still did function slightly less, but the temporalis basically temporalis shuts off,

[Jaz]
which is how anterior mid point stop appliances, you know, the main roadblock now function.

[Andy]
Exactly. And one of the ways that I’ve been taught, you know, with I get a really, really challenging patients is a lot of pain locked up, you put a little Juicy J again, and just send them away. And I would still do that, consider doing that to this day. Because whilst I’m saying we should turn muscles on, we want strong muscle function, you can over work a muscle, just like you and I go to the gym, and suddenly we start working on something and you know, it’ll be painful in your arm or whatever it is. But we shouldn’t be necessarily switching muscles off in if we’re aiming for long term good or good health and function. Okay? It’s gently, that would just be a small interim stage. So anterior, but all that temporalis switched off masseter still works a bit. Now that when you put it on one side at the back, okay, you find that the opposite temporalis switch is off. I’ve been waiting to be able to feel it there. But what you want to do is when do it with nothing, I have to I think at all, and get it onto your temporalis and you should feel hopefully not only a good volume of contraction, but also quite coordinated as well.

[Jaz]
Yep, coordination and yet, but a decent volume. Yep.

[Andy]
Okay, now you put a tongue blade in on one side, just posterior. And you should feel that the opposite side is either [inaudible] [Jaz]
See, I’m one of these freaks. I’m just being very honest. When they speak, I think it’s less, but it’s not as much as when I do something like this on my patients. A lot of my patients, they would switch off or be significant less, I’m a bit less. So I in principle, I can vouch for that. I’m just a freak. I’m very parafunctional patient. I’ve got quite hypertrophic muscles myself. But yes, there is a difference between the side where I’ve got the wooden spatula, which is contracting normally and the other one, or well, and the other one is not contracting as much in Yeah.

[Andy]
Well, one thing that might be happening is actually you’ve not got really good volume either side. Because the other thing then they did was when they found that the optimal a maximal contraction and coordination was when they put cotton rolls in between teeth, it was better than the clench. So let’s put it in both sides now. A really clench. Certainly in my mouth. I’ve got more volume. Right? So now if you compare it, I think you’ll find it. Certainly My mouth is less volume than I had on this slide. Then when I had both of them in there.

[Jaz]
Absolutely.

[Andy]
So the maximum contraction and coordination was when they had cotton rolls in there, which was mimicking food, basically. So let’s think what’s happening though, because you started to talk about, and when you have an anterior contact, that it’s affecting the ability of the condyle to really seat. Okay? So if we think about this here, what’s happening, when you’re biting down on this side, this condyle has shifted over to the left. And it’s because there’s no contact on the teeth [inaudible] And the muscles will not contract, because it’s not in a stable position. As soon as you get a contact on that side, the muscles will then contract, right? So you need the contract on the both sides before the muscles will contract. And that really allows the condyles to seat. Okay? Because So essentially, there’s condyles in space. Until you get a contract on that side. Now that we don’t eat like this, we eat like this. So you have to have contact throughout that movement, which means that you have contact on the nonworking inside. So when we shift over to this site, you still need contact on this site, you should not have immediate disclusion.

[Jaz]
Because that will be an unsupported joint on the other side.

[Andy]
Exactly. So this is I mean, it’s an inference from the data. But why does the, Why did the muscles contract maximally and in most coordinated way? It is because we think is because it allows that condyle a really seat and disorders tubercle. Okay? Now we know is always tubercle is the is the point of greatest force, because that’s where the bone is thickest. And the cartilage is thickest. Okay? Now, there’s an area here as or as tubercle is an area of contact, which also says is not one position for the condyle. Okay, it moves around. I don’t know if you ever saw that X ray movie, they could never do it today, or somebody I know a whole side extra with somebody chewing

[Jaz]
I’ve seen it’s like a lateral skull view of them is chewing.

[Andy]
What’s the condyle doing? It’s doing this.

[Jaz]
A lot of movement.

[Andy]
And the point is, this is what it does in function. And one of the problems that I had in my training is that you know, when we look at the way in which the teeth occlude together, and we slide on from side to side, and things like that, we’re looking at these gliding movements. We’re not really look at them now looking at them in function. Now that brings me on to the the other exercise I do when we do a course. Okay, and this is referencing [Bayron’s] work back from 1964. So Bayron looked at occlusal contacts and the difference between occlusal contact in function and in gliding movements. So we can do this now. You and me, okay? /-sure./ So put your teeth together and glide out on your on the side, on your preferred side, it doesn’t matter which side. Okay? I go out to the left. All the way out. And which I’m contacting on my left canine now.

[Jaz]
I’m very much in group function.

[Andy]
So you got group function. Okay. So are you going off to the left as well?

[Jaz]
I’m just going to the right now

[Andy]
To the right. And so if you’re going off to the right, and the teeth and the left coming apart?

[Jaz]
The amount of force I’m doing this and it’s just a normal, like you said, a glide. So just just yeah, just keep contacting, rubbing if you’d like skirting to my right. So know that my I have separation on my other side.

[Andy]
Right. So you’ve got group function with posterior discusion on the opposite side. Okay. Now just slide out to preferred side again, about a third of the way out. And this time, you’re going to crunch back with force. Okay? And just feel what’s happening on that opposite side, as you come back in to MIP.

[Jaz]
Okay, as I came in, and just when I was almost there, I felt a contact on the other side and my masseter I felt my masseter a contract on the left side,

[Andy]
Right. So you, you felt the end with force, there’s not immediate posterior disclusion. Okay, so when you glide, there is, but when you put force on, when you apply functional forces, the teeth come into contact. So, when I’m trying to explain the difference between what I’ve been taught as canine guided occlusion in the past, and the way what we teach in posterior guided occlusion now, I say there’s two ways of looking at it. There’s a sort of Structural way. And there’s it’s either about the structure or it’s about the function. And posterior guide occlusion is about function. Because when you look at occlusion with function, you have to factor in this there’s compression of the joint, okay? The bones compressing, the periodontal ligament’s changing and any although it’s a fraction of a millimeter it’s a significant fraction teeth come into contact. And we know through our Loughborough research that’s which is the muscles on

[Jaz]
which year was that Loughborough research by the way?

[Andy]
off the top of my head if we had the slides it’ll be on the slide show 2007? It’s the Journal of oral rehabilitation. We’ve done another couple of studies there as well. And I might we might get into that one.

[Jaz]
Sure.

[Andy]
What Ron was describing was actually confirmed then it was just confirming what was Bayron research done way back in 1964. And when you do it with Dentists we’ve done it all our study clubs, you get something I forget what it is exactly about 40 or 50 60% of canine guided about 30% are group function. And every now and again you get somebody who’s got function both sides they got contact both sides. When we ask them to bite back with force, you find about two thirds start to feel that nonworking side contact show and we then going with silk occlusal silk marking paper, okay? You find that contact on 100% of dentists. Okay, it’s just that we’re not always aware of it

[Andy]
So this posterior guided occlusion is coming out of what we see in nature. Right then so back to Ron Presswood Okay. One of the things that happened Ron and Henry have been working together on this thing and they’ve got this idea that this is the way that occlusion should be because it’s patient driven. And he was to do minimal adjustment to the occlusion, you know, I was taught, you know, massive amounts of equilibration and you have to dot dot dot stripe, dot, dot dot, you know, they were doing just touching here and there because it was patient driven. The patients were getting better. So Ron’s at a party

[Jaz]
that was on splints, or that was occlusal equilibrations or both?

[Andy]
I’ve done a equilibration course at Pankey, I think I may have done it twice, actually. And you know, we would aim to get that those dot dot dot stripe, dot, dot dot on every patient,Okay?

[Jaz]
and that was very different to what Ron was doing.

[Andy]
Exactly, because Ron and Henry saying, Well, actually, you don’t really need the canines, necessarily, it’s really what’s happening here. And you certainly don’t want posterior disclusion in that initial, what we call centrum thing,

[Jaz]
That is with force.

[Andy]
Well, because we’re interested in function, right? Then you should aim to build if you’re, if you are building somebody occlusion, you should aim to build in the ability for that normal side contact to come in. And actually, I’m going to bring you on to my next proo now. I hope you can see this. See this little spoon?

[Jaz]
Yes.

[Andy]
Okay. And if you look at my ebook, I tried to build this into the pictures. If you imagine that’s where the centric stop is. Okay? And if this is the lower right second molar, as you move over to the patient’s left, they should right up and down.

[Jaz]
And your finger there is the palatal cusp of the upper first molar or second molar.

[Andy]
Exactly. Doesn’t matter which could be a first or second molar. But that’s the contact that you’re looking for. Okay? There’s a little Centrum a little bowl to allow a little bit of movement. And then as soon as they start to move off to one side, it rides up, at least for the first millimeter or so that posterior guide. Now we call that a guide now, up until really understanding Ron’s work, if I saw that I’d be grinding away, again, because that shows me we’ve got haven’t got posterior disclusion.

[Jaz]
So yeah, and that’s what we’re classically taught as a non working side interference and interferences are bad. You know, Well, this is not why I believe in but this is obviously because for me nowadays, with the way I look at it in my map of the world is that they are not interferences, they are just non working side guidances. Now, what you’re throwing on the table is, is even you know, is making me very excited. And we got about a whole bunch of questions for you at the end just to debate this and explore this because this is really great. But one thing I just want to highlight now when you’re discussing the centrums, and the contacts is that the reason I read resonated with you and the reason I was so excited to bring you on the podcast for everyone to listen to was yes, you offer a 180 degree viewpoint. I think it should be heard by everyone. But you’re the first person who I’ve read in a book. And maybe that’s because you know, you may argue all you haven’t read all the books or whatnot, be the first person I actually read about the fact that most people who you think are in canine guidance, as soon as they put force and today go to one side, they’re no longer there actually in group function. So when I read that, hang on a minute, yes, this, I need to actually hear out what you’re trying to say. That was one on one kudos point.

[Andy]
Right. And so you know, that’s Bayron’s work back in 64. But, you know, if you don’t like that idea, you’re probably not gonna even look at that. Okay. But one of the things that Ron is very open minded, and he is the only person I know, who’s gone back to look at every single book on occlusion and read every single book. Right? And he went back, what happens is you get Dawson. And a Dawson then would see reference [ ? ]Yep. So you get gi Shea and gi Shea references, whoever it is, okay. And it goes all the way back to this chart called Bonwill in 1884. Now, I told you I’ve been doing social science research. Okay. So this is, what I understand is you have to understand the social history of what we how we learn and what we learn about. So I’m going to give a little bit of social history now of occlusion. Why do we think of occlusion the way we think about it?

[Jaz]
Is that a rhetorical question or you want to answer that?

[Andy]
Well, this is actually Ron’s. Ron is such a detail man. He says, I’ve got to find why we think the way we think because it’s not matching what I’m seeing in the real patients, right, and other bits of evidence. So it goes all the way back to Bonwill. Bonwill was the first person in English anyway, to write about occlusion he was a very well known dentist 1884 he writes this paper, and he says the body is designed on a set of equilateral triangles. Okay? Most clearly manifest in the mouth and jaws. And in the mouth, and jaws is based on a four inch equilateral triangle, four inches from here to here, and four inches from here to here. Okay? So where did he get this information from? In his article, right? In the article, he says, I had a dream, I was visited by God. And he described to me the way that the body is made up. Now we’re laughing but in those times, God was part of the science. Okay. And here’s some people say I said he stole part of science, fair play. But so anyway, we’re four inches from here to here and four inches from here to here. So it tells me two things. I don’t know about your God, Jaz, but Bonwill’s God was clearly English because he used Imperial measurements, okay? Right? And second thing it tells you, is it tells you the body is symmetrical. Because we’re four inches from here to here and four inches from here to here. Now, how many patients have you seen who are truly symmetrical in the physical form?

[Jaz]
Well, having done a diploma in orthodontics, one thing I started looking at more was faces. You know, I really went from identifying looking at teeth looking at faces, and right at the moment you go on Photoshop or keynote, and you flip transversely the patient’s photo, they look like a different person.

[Andy]
Yes. Symmetry does not happen in nature. It’s not natural. Okay. So who was a student of Bonwill, a certain chap called Edward Angle and he then got into detail about describing the way the teeth meet together. His angles class one, class two, or class three. And he references Bonwill, he was a student of Bonwill’s. And so suddenly Dentists have got this thing Oh, yeah, this looks right. Okay, now another part of our research team is a dental technician called John Bill okay? And John, because he really got into this as well, he looked into the history of articulators so around about the turn of the century 1800s and 1900s when Angles was coming up with his ideas, Ron and also seeing papers on a functional view of occlusion and being challenged by the structural view of occlusion so as Angle and Bonwill, the structural people, you know, you healthy when you like this, okay? And the functional people say, well, it’s don’t matter so much how you are. It’s whether you can chew or not. And there was this sort of competing ideas at the time. Now, the articulator manufacturers would go to both camps and say, Tell us what you want, we’ll build you an articulator. Now the structural people, their mass was normal standard nonlinear mass, okay, because it’s easy to describe, it’s like a hinge, it’s symmetrical. Okay? The functional people couldn’t describe exactly what they wanted, because that is based on nonlinear maths. And the condylar movement and occlusal function is nonlinear. And nonlinear mass did not exist at the turn of the century. So basically, they are to articulate the manufacturers piling with the structural guys, and then somebody’s got something to sell. So it starts to build up from that, and these functional people, you know, got, they didn’t have it couldn’t really compete with that, or whatever. And frankly, I don’t know you’re not not old. But I can tell you a lot of my friends and colleagues are qualified when I did never bother with occlusion throughout the whole career. And they just go on with life in their way. Okay, and nobody died pretty much. So basically the structural piece, that’s why the structural ideas got took hold. And then it all leads up to people like Kois, Dawson, I’m not so sure about Kois, to be honest, because I hear that, you know, he’s far more functional. But you know, the Dawson’s in this world cliches. And certainly orthodontics For God’s sake, your orthodontist used to be taught, you got to treat a class one, you know, and get the patient the class one. And that’s why that dentist’s daughter had four falls out, she had to get the class one, molar class one and all that sort of stuff. I mean, it’s it pervades everything that we think about. So I teach it on the diploma. We do look at other class one, two, or three, but I say to people, look, this is not a treatment aim, it’s just a description. And if you know, you know how far they are, from this reference point of class one doesn’t mean to say you should treat a class one, because you have to treat according to the needs of the patient. And patients are not symmetrical. And some people skeletal patterns are more two, some people more three, what you’re looking for is a functional occlusion. And you can have a functional occlusion with a six millimeter overjet, you can have it with a minus three millimeter overjet. And you can be in a terrible, terrible pain if you have class one. And you know, too many overjet anterior contacts. It doesn’t relate to whether their own pain or good functional. It’s not related. So how do I get it? So basically, I was telling you where

[Jaz]
You’re refreshing those you know, that’s very refreshing to hear about. Now We don’t have to treat everyone to class one, but still on as far as I can see on postgraduate degrees and degrees in orthodontics, they still teach Roth. Roth is five sort of principles, which very much echoes from Angles and Andrews and go continues on from there.

[Andy]
Yeah, it’s part of the structural School of orthodontics. Okay, what I would say, and so when I try and make a difference for people, I say, well, you either, you know, this is a structural way of looking at it, we have a functional way of looking at it.

[Jaz]
Okay, but Andy, most specialist would call that if you say to a specialist, well, in this case, we can accept the degree of class two in this case, they would then say, okay, so you’re going for a compromised treatment plan. And that term then makes it almost undermined your entire thought process and what you’re trying to do for the patient,

[Andy]
Right. And so, we have the evidence to show that the compromised so called is actually the best way of treating this patient. Because I’m going to give you know, probably because we’ve been going on a bit but I’m going to give you what I think is the killer piece of evidence. Okay?

Jaz’s Outro: So that’s quite heavy stuff. I hope you enjoyed some Andy stories of the origins. Next episode, we’re going to go really deep into PGO. And we’ll also talk about how Andy applies PGO actually clinically, to his patients and what he’s looking for in his Invisalign patients towards the end of the treatment protocols. So I look forward to catching you for part two of PGO.