OK, everybody, welcome to tonight's webinar with the webinar vet. My name's Sophie McMurra, and I have the pleasure of sharing tonight's webinar with Sam Hall. So before I go on to introduce Sam, I'd just like to point out that you can ask questions throughout the webinar.

If you hover over your screen, there's usually a toolbar at the top or the bottom of your screen. Click the Q&A box, type your question in, and that'll come straight through to me. You can send them during the webinar, it won't disrupt anything, and then I'll just read them out at the end.

OK, so tonight we have Sam speaking to us on an update on modern equine dentistry. Sam has spent over 20 years in the pursuit of providing better oral health care for horses via equine dental training, both in the UK and USA. 2 undergraduate degrees and 2 postgraduate veterinary certificates, and a postgraduate veterinary diploma, it's pretty impressive.

Sam was awarded the RCVS certificate in Advanced veterinary practise, the CAFAVP in equine dentistry in 2012. The first to be awarded by the RTVS. In 2015, Sam became an RTVS recognised advanced practitioner in both equine dentistry and equine practise.

In 2016, Sam became one of only a handful of clinicians to become a diplomat in the EVDC via the equine fast track pathway by successfully passing the entrance examinations. Sam has also tutored on courses and spoken at conferences on equine dentistry for over 10 years and has authored and co-authored several journal papers on equine veterinary dentistry. So we have a row here tonight with us.

So on that note, Sam, I will hand over to you. Thank you very much for your kind introduction, Sophie, that's awfully kind. Well, I'm not sure how many pearls of wisdom I can give you tonight, but I'll try.

It's always very difficult with these webinars when you don't really know who your audience is of where to pitch the level of dentistry. So it's gonna be quite broad strokes of, of where we're at with modern equine dentistry at the moment and hopefully whatever level you're at with your practise at the moment, there's, there's a at least a couple of things you can, you can take forward from today. So just a little synopsis of, of what we're gonna get over the next hour or so, it's really an overview of, of the new research and techniques that have evolved in equine veterinary dentistry over the last few years and specifically about the last 10 to 15 years, because there's, there's been a big jump forward in, in actually treating equine dentistry like a, a modern science from the basic.

Of tooth raspring and some pretty prehistoric extraction techniques about 1015 years ago to to modern dentistry methods as restorative dentistry, endodontics, periodontal treatments, and, and now we're getting into a lot of scope oriented, minimally invasive standing surgery techniques coming into, into equine dentistry, which is all very exciting. And off the back of this from About 58 years ago there started to be subspecialties in both North America and Europe now in equine veterinary dentistry. So hopefully during this presentation I can highlight some of these advantages that you may or may not have heard about.

And, and basically throughout this whole presentation, I've tried to base everything that I'm showing you tonight on evidence-based research and primarily from peer reviewed sources where I, where it's available. There are still some gaps in our knowledge in, in this area, but where possible, I've tried to make it as robust as possible for you guys. So the learning objectives hopefully improve your knowledge unless you're asleep and increase awareness of some of the recent research within equine dentistry that's out there's been a big kind of plume of, of, of good quality veterinary research that's come out in this area, and hopefully an increased awareness of some of the new techniques that are out there, a few practical tips I can impart, and, and, and a bit of clinical reflection on, on the evidence base that's out there and maybe how this can inform what you do in practise.

OK, so just a brief summary of what we're gonna try and get through and, and this is a bit of a general overview, cos I could probably spend an hour on each one of the points on this slide. But basically regarding dental disease and its diagnos diagnosis, we're gonna look at radiography, oral endoscopy, and, and the use of standing computer tomography within trying to diagnose dental disease. And then when it comes to dental disease and its management.

How regional anaesthesia can help you, EOTRH, which is a reasonably recently discovered, equine dental syndrome, infant disease, maloclusion correction, we're gonna look at some periodontal disease as well, and also some of the advances in minimally invasive dental surgery. And just a couple of slides on the end on TMJ disease as well, because it can sometimes be a bit of a hot topic in the, equine world, especially with, Some of the sports medicine clinicians and things like that. So it will be a bit of a gallop through, but hopefully you guys can bear with me.

So, starting off with radiography, so what's good about radiography and trying to use that in your dental practise? Well, it's readily available, pretty much every equine practise I know of has radiography and most now have CR or DR. It's non-painful, it's non-invasive, and you know, it's relatively cheap, all things considered.

But what are the downsides with it, well you need protective clothing and the safety. Parameters that come with that, gowns, gloves, thyroid guards, you need a dose metre, you need to be in liaising with your RPA. To try and minimise the exposure issues, you need to use a cassette holder to keep your.

Hold her away, and I can't advocate strongly enough using a headstand to take equine dental radiographs and sedation. If you're not sure the horse isn't, is sedated well enough to take the radiograph, it definitely isn't, and you need to give it a top up because horses move, you have to repeat the exposure, and then you, you know, the risk is far increased. So yeah, biggest tips, lots of sedation and use a headstand.

I'm also not a big fan of taking dental radiographs out in the field or on yards and things because you're not in control of the environment and it only takes, you know, ladies to knock a wheelbarrow over, etc. Etc. And it's it's just very difficult to get the environment to take good radiographs.

But what can we use radio? Grass for, they're really useful in the diagnosis of apical dental disease, fractured teeth and bones, periodontal disease, endontic disease, sinus disease, and temporary mandibular joint disease also. So, just another key point with with radiography, as I'm sure you all know, is that you're producing a 2D image of a 3D structure, therefore, to try and make any.

Diagnosis of any degree of certainty, you do need to take a minimum of two views of that structure required. So for example, a lateral and oblique or an oblique and a DV just so you can try and hone in on that radiographic diagnosis. And, and this is just a list of the dental views that we commonly use, you know, we've got free laterals for sinusitis, we've got supported lateral lateral views, but you get a lot of super.

Position in that, you've obviously got your maxillary and your mandibular oblique views, and DUVs, offset DVs. Intraor views, they're very popular in America, and they're not so popular over here. We can talk about those a little bit later.

Open mouth oblique views have become quite popular, especially for looking at some diastomma work and some periodontal disease. TMJ views, can give you very good images. I find them very frustrating to do.

I think there's a poor tolerance to get good images and then, and then don't forget lesion orientated views. If you've got a big swelling on a horse's mandilla, mandibular or maxteria, don't forget, you know, put a nice marker on it and, and take an oblique that highlights that, that swelling or that draining tract, and that can be really, really useful. For those of you that might not be aware of the open mouth or bleed view, it's a really nice image from a radiography book by Weaver and and Barracka, which I'll talk to you about in a little bit, which just shows that you can highlight the clinical crowns on this image here, and you can look at the angle of teeth, if there's any diastomata, crown fractures, stuff like that.

So this is the textbook I was talking about. I think it might be out of print at the moment, but if you can get a copy, it's quite small, so it can fit in your car if you're an ambulatory vet, not just for the dental images, for all, all your views and stuff. It's a really good little reference book.

It's really practically orientated like the review and the vet record said, and, and I can't really recommend this book highly enough. So, looking at dental radiography, how can we put some evidence-based medicine on this and try and help you guys make your decision making a little bit more robust? Well, Nicole Dutoit, who is a, is a diplomat who works in this country, she wrote a critic clear plays topic in Eve, a little while ago that said, does radiography help or hinder in apical infection?

So basically, does it help you diagnose whether there's an a or a periaapical infection in one of your dent. Cases. We know that trying to interpret these images, particularly the maxillary cheek teeth is very complicated because there's complex anatomical structures there and you've got lots of superimposition going on.

So it can be very difficult to try and separate the wood from the trees, but. In this, in this clinically appraised article, and Nicole looked at two blinded case control studies by Weller and Townsend, and, and basically looked at the evidence that was there, and basically what she concluded was that radiography is not a hindrance to the investigation of dental disease and is an essential part of the workup for a suspected atypical infection. As long as the clinician understands the limitations of radiography.

And, and there is some variations in specificity and, and, and, and, sensitivity with dental radiographs. So if you see something that looks quite conclusive on radiography, it is probably true, and there is probably an apical infection there. If you see something that is equivocal.

Don't be so sure that there probably is apical disease there and that's the take home from the sensitivity and specificity in in dental radiography. So, moving on to the next bit of of dental disease and diagnostic, oral endoscopy, it's really improved the diagnostics within the oral cavity of the horse, and I don't think it would be too much of an overstatement. So this is slightly revolutionised how, how we're looking in the mouth.

The introduction of mirrors was great, but actually being able to show on a big screen known as what's going on and describe. Pathologies to them in some detail is really, really good. It's safe and it's non-invasive, and this was proved back in 2008 by a lovely paper by Simhofer, and it's been shown to be superior to a clinical oral exam trying to identify disease teeth.

And actually in a, in a paper in 2009 by Pete Ramzan, 88% of cases in which oral endoscopy was used, it revealed a visible change. With the tooth that was implicated. So, you know, there was either a fracture of his tooth, a secondary dentinal defect or a, a draining tract within the perdontium of this teeth.

So that gives you a lot of confidence that you've got your diagnosis right, if you can find these things in. In the oral cavity with an oral scope. Now, they, they're not cheap, and, you know, you have to look after them because they can be a little bit vulnerable in the mouth.

But if you're doing a reasonable amount of equine dentistry in your practise, it is a bit of kit that really you should strongly consider investing in. So here's just a little image, and I've had to borrow a a video of oral endoscopy from Justine Kane Smith, who's a specialist that works at Livepool University because I've had some issues with my capture unit at work and trying to extract videos from it has proved very challenging. So thank you very much to Justine for letting me steal a video from her.

But as you can see here, this is the 206, you're looking up at the upper left maxillary arcade, and, and what you can do is, oh, excuse me, see if we can start this image again. There we go. And you can see there's a, it's quite a marked grade 3 medial inandibular carries there, moving on to the 7, and there's a little fissure fracture associated with the 3rd pulp horn.

Here on the 8th, there's a secondary dental defect on that. Second number 2 pulp form there. Again, some infant diaries, probably grade 2 there and going back to the 11 there where you can see a, a fissure fracture running between pulp number 1 and number 2 there.

So you can see a lot of detail in a scope like that, and, and that was quite a gallop down that arcade, but you can go back, you can review it, and you can particularly explain these things. To an owner without them trying to peer over your shoulder and look at a dental mirror like we had to do for so many years. So then moving on to standing computer tomography or a CT scan as we all know it.

We're very lucky in the UK compared to other parts of the world that at Rainbow equine Hospital, the late Alistair Walsh, he pioneered this, and it, and it's really been a big leap forward because you don't have all the risk and mortality associated with the general anaesthetic, . You know, I think there are almost 10 standing CT units within the UK, so you're never too far away from one and we are very blessed, and most of them work on a hydraulic sliding platform where all the friction is taking off the horse, so actually, The standard human table that you or I would pass through the, the centre of the scanner can be used just to draw the horse's head, usually out of the scanner. We put them in and then the scanner actually takes as the horse is retracted out of the, out of the scanner, and, and this is a Picture that's kindly given to me by Henry Tremain from their, their scanner at Bristol University from when he was there.

And this can be used to make very high detail images like this, this volume rendered reconstruction on the right here where you can take slices through the teeth and and and reorientate them, and it, it really is at the moment, the kind of gold standard we've got on diagnosing dental pathology and horses. So again, Justina's kindly let me steal one of her videos as I wasn't being able to access mine, and this is just a fly through of a of a standard CT scan from a horse. So starting from just behind the pole, and we're coming forward with the wing of the atlas of the occipital joint here, going into the guttural pouches you can see now on the larynx, and then the back of the mandible just coming into view now with the hyoid bones just sectioning the guttural pouches there.

Here's your TMJ joints and your. Brain is coming into view there and then you've got your ethmoids and your perinasal sinuses that are starting to come forward now. Your cheek teeth are just about to start coming in now, you can see your orbiter as well, and they're just gonna work rostering now as we're just working our way through these cheek teeth as we're working down the arcade.

You can see all the interactions of the sinus anatomy here, which isn't straightforward, and now into that nasal meatta and the concordbuller as well. And then in a minute, we're just gonna hit the incidental space now, and then you'll see the maxillary bone separating into the incisive bone. And then I think on this video, we can just see the, the lower incisors come into view as well then.

So it does show that you can get really, really good high quality images on a CT scan. Obviously, that's just a fly through, so you can, you can look at those slice by slice and really, really drill down on the detail. Just a note on that, so this image on the left of the screen here is a transverse section as the CT scanner gets, you can see this is very good detail.

Now you can look at the scanner in any plane you want through something called multiplanar reconstruction, but do bear in mind that when you do that, the quality of the image does drop significantly because that's not the true data, that's the data that the computer programme is reformatting. Back together, and that does depend on the software you're using to reconstitute the image, etc. Etc.

And then on the far right is a volume rendering 3D reconstruction, and owners quite like them and they can be quite good for surgical planning, but as far as diagnostic, you can see. And the detail just drops on that image again. So do bear that in mind if you're ever looking at CT images and trying to interpret them, is, is this true data or has the computer filled in the blanks to give me a multiplayer reconstruction or a volume rendered model?

But there's been some scan then some research studies on. Computer tomography scans relating to dentistry now because it's been around a little while now. We've had some studies on abnormal cheek teeth, in fundibular lesions, adontogenic tumours, and also the merits of CT versus MRI, and they're all quite interesting.

Just put these two images from two peer reviewed papers here, one by Carsten Stay on the left and the paper by Morgan on a adontogenic tumours on the right. And, and these are some lovely volume rendered images, particularly that one of the tumour on the right, and then this really elaborate reconstruction through multiplanes of an incised tooth here. But just bear in mind, these aren't the sorts of images that most people have the computing power to regenerate when you're looking at images.

You know, these are very top end regenerated images with very, very powerful computers, but they can undoubtedly produce some really, really stunning images. So, just moving on to some dental disease and its management, and I quite like to use the phrase management rather than treated because there is a lot of dental disease out there, particularly with horses, where we can manage it to a greater or lesser degree. We can't always completely fix or treat these pathologies that we do find in horses.

So let's start with regional analgesia. And regional analgesia or, or nerve blocks in combination with the use of constant rate infusions of modern sedatives, particularly alpha 2s, has massively changed dentistry for the better. When I first started, the majority of cheek teeth were extracted under a general anaesthetic.

If that's very tricky, trying to do an oral extraction under general anaesthetic, your orientation, everything is very wrong, and if that didn't go well, then you tended to go to repulsions. There used to be a lot of collateral damage, a lot of complications and comorbidities going with that. So, the fact that now, We do the vast majority, I'd say well over 90, 95% of the procedures done in, in my clinic are done standing now, and most of the ones that are done under general anaesthetic are actually done for temperament reasons.

Now, a horse, you know, simply won't tolerate you hammering. Their head unless they're under GA or dripping through their sinus or something like that. So, the vast majority now with, with good regional analgesia and, and a, and a good grip on constant rate infusions and, and the drugs and, and how we can implement them, and, you know, has, has really made the, the morbidity rates of this a lot better.

So, what are the different dental nerve blocks that we can use? Well, local blocks are, are, are never, never, you know, Not to be used, you know, wolf teeth, and local blocks around them, if they're small ones, and then it's not a very old horse, will be more than enough to really revolutionise taking your wolf's teeth out if you're not using a local block for that. All the textbooks say that these, these specific dental nerve blocks will numb the ginger bat, and in my experience, that just simply isn't the case.

So whatever nerve block you are implementing, I would fully encourage you just to infiltrate. Local around the ginger margin of any tooth you're wanting to work on because it will make your life an awful lot easier. You've obviously got the mental block through the mental framing, which is number 8 on this, this image here that I've kindly borrowed from, from Henry Tremain's paper on dental nerve, nerve blocks.

And you've got infraorbital, which is number 6 here, that nerve there and the, and the, frame and just here on this image. Got the palatine, which is, is this one that just comes on the inside of the cheek through there. You've got that mandibular nerve, which gets blocked on the.

Axial side of the, mandible here, the maxillary nerve, which is blocked behind the eye. There are a few different approaches to that, and, and it's a really, really valuable block, but there are potentially a few more complications that go with that blocks and some of the others. And obviously, the temporal mandibular joint can be anaesthetized like any joint can be, and that's, that's pretty, informative when it comes to trying to diagnose any potential TMJ pathologies that, that may or may not be going on.

So let's try and lay some evidence-based medicine over this again for you. So again, Nicole De Toit and did another critically placed topic and which nerve blocks will help me with a tooth extraction? And what she did is she looked at a variety of papers that have been published on this, on these, techniques, and she looked and found that there was no significant difference between the two of the different maxillary nerve block techniques.

And what she looked at was the paper that looked at the extra ocular fat body infusion technique versus the lateral approach, OK? So the image on the left here shows the fat body which sits just under the eye and you inject the locally into the fat body just below the eye and that infuses into the nerve. You have to use a higher volume, you have to wait a little bit longer, but the complications are lower.

And then on the right from the barle paper is an image just showing the, the lateral, the lateral rostral approach using a spinal needle to go right to the. Frame and below the eye. That's far more accurate, so you don't have to use so much volume, but there is potentially more complications, particularly retrobar hematoma.

But both approaches were successful in about 80% of nerve blocks performed. And as I was saying, the extra ocular fat body infusion techniques had a reduced risk of potential complications. And then another paper by Harding Eel looked at an angled approach for the mandibular nerve block versus a perpendicular approach and found that there was no significant difference.

It was successful 73% of the time with the angled approach versus 59% with the perpendicular approach. That is a, a better outcome with the angle approach, but that difference wasn't statistically significant. I personally do use the angle approach, and that paper just could make me a little bit more confident that at least the approach I was using, the one that had a slight marginal gain on the paper, even if that wasn't statistically significant.

The mandibular nerve block, there's been an intra approach that's been recently described by, Henrietta, and, and, and this potentially reduces the potential complication of anaesthetizing the lingual nerve. Most of the time when you use the, the, the standard angled approach from mandibu nerve block, you will get. Paralysis of the tongue, and that does mean that they can sometimes cause some trauma to their tongue, post the procedure when they're trying to eat and come back on.

So do starve them for an extended period of time, and, and never bilaterally nerve block, a mandible if you're doing that, because you can, can get some pretty horrendous outcomes. So, so what did Nicole conclude? Well, she concludes that there's no difference in the different techniques you use to perform dental nerve blocks.

You should obviously use them and implement them, but actually, which of the approaches and techniques you use doesn't have a significant impact. So, the other thing I just wanted to highlight from this thing from another peer reviewed paper by Antana and Hubble was just that dental nerve blocks should be considered as safe. So this pair looked at 162 equine patients and where they did 270 regional nerve blocks, and only 8 complications were identified in only 7 patients.

And that's an incidence of less than 3%. And, and, and what were these? Well, I had 3 supraorbital hematomas that I just mentioned, a local hematoma, some lingual self trauma that I was just mentioning in the previous slide, and, and one failure of the block.

And, and this image from Carsten Starzak, who's a really amazing autonomist from . Over on the continent just shows where the needle goes to the extraor orbital fat pod technique and just where the artery is quite close to the nerve there. So there isn't a lot of scope when you're putting the needle in directly, but that's where the advantage of this diffusion block comes in, but.

Even using those more specific techniques, you know, an instance of less than 3% I think is, is very easy to discuss with owners and, and, and explain why benefits far outweigh the risks of the complications. OK, so just moving on to EOTRH and for any of you that aren't familiar with this, this stands for equineodontoclastic teeth resorption and hypercementosis. And we describe it as a syndrome.

So it affects horses and ponies, and it probably affects donkeys and mules, and I'm not aware that's been reported to date. Adontoclast, the cells responsible for the resorption of dental materials, so that's cementum, dentin, and enamel. The teeth involved with horses as radicular hypsodonts, and resorption is the lysis and the assimilation of the substance such as tooth and bone, and this happens within this process as well.

And, and hypercementosis is the addition of cementum to tooth to try and firm up these teeth when they've undergone the resorption process and. There is some papers out there that are trying to suggest that EOTRH comes in different forms. I can be a predominantly resorptive form or predominantly cementosis form.

Myself personally and, and Carsten Stasi, who I've authored a paper with on this, we believe that it's the same disease. You're just seeing it at different points in the disease process. It was first described clinically by Clue in 2004 and then CA and Starzi first did a really lovely pathological study on it and where they looked at at at slices through the microscope, etc.

In 2008 and this was really the first time this this disease syndrome had been had been noted. So myself and and Carsten Stark, we did a review article on this a few years back and, and, and basically the, the kind of take home messages from it is, it's a progressive and painful disease syndrome. It affects age horses, and that's primarily kind of over 1415 years of age, affects incisors, canines, and infrequently cheek teeth, and it tends to work in, in, in a rostro cord or a medial to distal fashion within the teeth involved.

And it's characterised by gingival inflammation, subgingival swellings, draining tracts, and this bulbous enlargement of teeth, which is shown lovely in this, this picture on the right here, or also resorption of teeth where basically just, just big swathes of the dental material is just lost. Diagnosis is based primarily on clinical presentation and and then backed up with the age profile of the horse and and the radiographic changes when you radiograph these cases. And treatment of EOTH is currently not possible.

There are some management strategies in which we feel you can maybe slow the progression, but in the end, unfortunately, these teeth, once they become significantly painful, mobile, and marked secondary periodontal disease, they really do need to be extracted. And sometimes we do whole mouth incisor instructions. So all 12 in insides of the teeth are extracted, and while that seems very radical.

The patients generally, you know, do very well and, and, and really, really do very well, have a massively improved quality of life after you've done this. So these are just some images, some of the images of myself, some of my colleagues of just some of the more significant EOTRH cases you can see and hopefully you can see these bulbous gingival swellings, resorption on teeth like you can see on here, you know, wearing teeth with big swelling on the gingiva, and these big kind of almost cannonball like swellings you get sub gingivally. And this is probably one of the worst cases I've ever seen.

It was a, a local EDT, Alex Jessie that sent this case, and basically the resorption was so bad that the gums had basically receded off these hyper cementoic teeth, and, and kind of left them just like tombstones sitting out the front, and it, you know, it was, you know, it's not a stretch to understand that this, this horse is going to be in chronic unrelenting dental pain. So just to try and put a little bit more detailed evidence on the top of it, a recent study by by Ry here looked at the, the radiological prevalence of EOCRH within horses, and really some lovely radiographic images here just highlighting the, the, the apical changes, the hyper cementosis, the marked hypercementosis, the lytic regions within it, and just really highlights, you know, what you can see when you radiograph these cases, you know, sometimes you are just seeing the tip. The iceberg on your clinical supra gingival exam and when you radiograph them, you can't quite believe what what your eyes are showing you.

And what this paper showed was that 94% of horses had at least minor radiological changes, OK? And that 62% had moderate to severe radiographical changes, and then no horse that was older than 14 years of age was without any radiological signs of EOT or age. That does just suggest.

If we look for it radiographically, we will find it. And all horses over 28 years of age had at least a moderate level of radiographic changes relating to EOTRH. So, you know, I think if you're dealing with older horses and your population of horses you deal with are aged, this is gonna be out there in your populations, and if you start looking for it and asking, does this patient have EOTRH, they will do.

And these are just some images, again, some from myself, some from my other colleagues that that just show some, some non-paper, some real life images that just so you can just see here, this is a very interesting image from Professor Nick at Edinburgh that shows that how marked the mineral density between two adjacent dental teeth can be on this image. Some really big swellings here with some big areas of lucency and resorption, and you know, to the point where these teeth are so brittle that they're spontaneously fracturing in this case here. So, moving on to infantdibular disease.

So This has become quite prevalent in the modern case load that we see, and it is always quite a hot topic to talk out at conferences. It was first observed at the turn of the century by Coya with a prevalence of about 13%, and, and then later on in the 1960s, and other reports said that, you know, there was a prevalence of 100% in maxillary cheek teeth of horses over 12 years of age. Well, that's a big swing in in prevalence there in, in, in 60 odd years, and I think probably some of these problems and changes in instances are how these lesions are being classified, and I'll talk to you a little bit more about that in a minute.

And in a recent study of 786 maxillary cheek tes from 33 horses, it found that only 11% of infant dibula were completely filled with normal, normal cementum all the way from top to bottom, and that does beg the question is, is. It's probably not normal to expect all infant dibular to be filled with perfect cement all the way from top to bottom, and areas of cemental hyperplasia that were observed in 22% of infantdibular is probably normal to a degree. But Obviously The carers process can then take hold and, and that can lead to to true caries which were found in 8% or 62% of the 786 pieces of the fundibular.

But just do bear in mind that the upper09s and maxillary Onis accounted for 47%, that's nearly half of all the carious teeth that were found in this tub in, in this study by Fitzgibbon. So, so massively nines and to a lesser degree, upper sixes are massively overrepresented, so bear that in mind when you're looking in the oral cavity. And only 10% of, of.

Mach3 nines that were examined by a CT scan were found to have normal inffedibular cementum formation in a CT study by Windley Atta from the Royal College. So just bear in mind that there are a lot of variations on normal, but having said that, that indiblicar is prevalent, particularly in the nines and to a lesser degree, the sixes as well. But said the difference in the prevalence of infant decay, I think, possibly comes down to the fact that that the three different classification systems, the first ones described by, Homer in 1962, and then Ian Dacus's PhD work in 2005, and then more recently, Professor Dixon's work from Edinburgh, does show there are some variations in how these legions and classified.

So in order to classify these lesions, you do just need to be, you know, quite on point with your occusal anatomy. So if you're not happy with your infant dibular, from your pulp horns and numbering your pulp horns and what's your peripheral cementum versus your. Your, infant dili cementum, you know, spend a bit of time just revising that anatomy, so you can be very clear in your own mind when you're doing a normal exam as what's what and, and is it normal and is it abnormal, if it's abnormal, what's affected?

And I would encourage people to use the pulp numbering system. Originally, in Day again in 2005 proposed, equine pulp numbering system, and this was just slightly modified by Nicole de To as part of her PhD in 2008, and, and, and basically the easiest one. For me to remember it is that with this revised system by Nicole Dutoit, is that the most rostro buckle pulp horn is always number one.

If you work, digitally from that, it goes 12, and then if you swap into the next line, 34, and 5, etc. Etc. So it's quite logical to work your way through it.

And yet this is the most up to date infant tubular grading system and proposed by Dickson SL in 2005 graded from 0 to 1. So, on the far left, this is grade zero, which is a normal tooth. There's, there's no macroscopic signs of any, any caries.

You can probably just see the remnant of the vascular channel within them. Then go to grade one, where it's only the cementum that's affected. Grade 2, where the cementum and the anomaly started to be affected.

Grade 3, when you get cementum, enamel, and it goes into the dentin, you can see the secondary dentinal defects on, on this tooth here, and then grade 4 where the integrity of the tooth has happened. So that's either inventdibu have coalesced, or in this picture, you've actually got a sagittal fracture right through the middle. So, the prevalence of infantdibular disease and infant diaries is associated with increasing age, the older they get, the more of it you're going to see.

And, and infantdibucas has sequelae. So what could it lead to? Well, apical infection.

So if the caries progresses through the infantipar enamel into the adjacent dentin, the dentin is connected to the pulp, something called the, the dentinop pulp complex, and you're gonna get a pulppitis at best, if not pulp or death on the back of this. And, and a study by Ian Dayer in 2007 showed that 16% of maxillary cheek teeth a factors were due to caries. And then eventually, when the tooth becomes.

So carious, you get a pathological dental fracture. Most often these are sagittal midline sagittal fractures, as I showed in the previous slide, but not always. And, and yet, it's a significant structural weakness.

And this is the rationale of why actually restoring some of these infant diblicar can have significant merit. And, and such fractures, if you do let them occur, do result in a infection 100% of the time in, in a study by Dickson EA in 2000. So.

If these teeth go on to break, they're gonna cause anapal infection, you know, and that has been proven. So, you know, a lot of the people out there say, 00, the tooth is just fractured, we're just gonna keep an eye on it. With what we now know, that's probably not OK any longer.

So just some images of obviously using the probe just to see little little areas of infant dibuy, seeing how deep they go. Little little files can sometimes be very helpful to see how far these, what can sometimes seem like very minor lesions go, because as this image from a nice paper by Barracks I Barnett shows. You know, on CT and on postmortem cross section, some of these lesions can go very, very deep apically.

So just because it's a little. Lesion on the occlusal surface doesn't mean it isn't a very deep lesion as well, so just do bear that in mind. And just as I said before, you know, there are practitioners out here, and, and I'm one of them days practising, infantylic car restorations.

I think picking the right cases, you don't want to go with ones that are are too high a grade, yet there is no reason to go filling every grade one and grade. Two lesions. So I think picking the right cases and also picking the right owners, I think is important, because just like with human restorations, you know, fillings can and do crack and fall out, and, and you need to have the right owners that understand that when they're first put in and aren't gonna suddenly, you know, make your life more difficult if any of these restorations do need replacing or revising.

And just going back to that previous image, you know, we quite often see air bubbles in them when we've done them, that's why I put these images there, and, and they're normal, that's, that's just because it's very hard to get a a a consistent fill right through with horses, with the techniques that we use, and quite often they will fracture. Chewing sit, but that doesn't mean that they, they're not solid and they have to come out as long as the restoration is firm on good probing. Then, then even if they do have some, some fractures within the fillings once you've done them, I don't think that's the reason to revise those restorations always.

So, moving on to periodontal disease, and I'm about 2/3 of the way through, so I think I'm, I'm doing OK for time, which is good. Yeah, periodontal disease, it's, it's basically inflammation that involves and disrupts one or more of the four components of the perdontium. So what are the four components of the perdontium?

The gingiva, the periodontal ligament. The cementum, or the peripheral cementum that that surrounds the tooth and the alveola bone, and that's what holds the teeth in the horse's head, for want of a better word. And, and a couple of really nice images I like here that again I've borrowed this one from, from Nick Moore from the states shows a cross sectional image here of just how Interdisposed the perdontium of this horses with the structures and particularly on this image where how close the perdontium is to the sinus.

So, so you can see how infected teeth and periodontal disease can work their way into sinus disease with with not too much of a leap here. And then the one on the right is a really lovely image from a paper by Custen Stars Academ that he published in 2004, just showing the different orientations of the gingival and, and the more apical fibres of the periodontal ligament that hold the tooth in situ and and how these teeth in. A young to ageing horse are almost suspended within the, within the alveolus like on a trampoline of, of, of wires, and I think that's really interesting to bear that in mind, particularly when you're, when you're taking teeth out, you can bear in mind that most of the periodontal ligaments are on the.

Coronal aspect of a young horse, whereas on an older horse, those periodontal ligaments are far more distributed down the length of the tooth, and that's why even geriatric teeth, when you think they're going to be very easy to get out, it's very easy to fracture these stubborn little thin roots at the bottom because of the periodontal anchorage they've got down at the bottom. So, Going on to talk about periodontal disease, more specifically in the equine species, it primarily revolves around disruption of the row of the six cheek teeth, because they're meant to act as one functional unit. And they do that by being kind of dovetailed in by the rostrochordal angulation of the 6th and the 11.

This image here, which was taken from a study by Miriam Casey when she did her residency at Bristol Vet School just shows by some angle on the 6 and some angle on the 11, it really nicely keeps the interproximal spaces all nicely tight there. Whereas on this in The intraural image that I took here shows that the 6 is quite upright, and even the 11 hasn't got much angulation. You can see that there are inter proximal spaces evident here, and even with some incidental bone loss here as well, and here.

And and that shows what actually that rotrochordal angulation is very important for the health of the of the row of cheek teeth. So, so what are these gaps that could occur between the cheek teeth? Well we turn them to Astomata, and these are detectable into proximal or interdental spaces between adjacent teeth, and why do they occur?

Well, primarily, in my opinion, it's due to poor angulation, as I showed on those previous radiographs, but it can also be due to displacements or rotations, media aversion, disdiversion. And, and, and actually just inappropriate spacing of teeth, sometimes the dental buds are just too far apart in certain horses to get good apposition of the cheek teeth. And also with age, the cheek teeth taper as they go down towards the roost.

So as a horse age, you do get what we term senile dastomata, and, and they're a very different subset of diastomata and periodontal disease. They commonly affect the caudal mandibular cheek teeth. I certainly see the vast majority between the lower nines, 10s and 11, and they're undoubtedly very, very painful.

And I see horses very commonly within, in my clinic, where you literally can't do their teeth without a truckload of sedation until you've blocked their lower jaw. Give them the periodontal disease some treatment, resolve that a little bit, and then they'll let you do their teeth normally quite uneventfully. So they can be very painful, quite often leads to quitting, poor condition, although it's surprising how often they can have terrible paradontal disease and still look at fat as a rhinoceros.

But poor behaviour, quite often once you treat this periodontal disease, they'll all say, oh, so much better now, but they never really perceived the problem to start with, so I always think that's very interesting. So trying to get a handle on periodontal disease in your cases, I'd encourage everyone to start using indices, so periodontal disease indices from 0 to 0. This is based on the percentage of attachment loss, and it's, it's come from humans and small animals industry.

That's not overly applicable in my opinion in equine industry. But, you know, having a grading industry from from index from 0 to 4, or even if it's just mild, moderate, severe, I think is, is very important, so you can follow up your cases and see whether your management is making an impact or not. And also to.

Mobility index. So 0 is no movement. OK, 1 is slight movement, 2 is moderate movement up to 3 millimetres, and 3 is severe movement up more than 3 millimetres.

And when you're trying to grade, you know, you're getting moderate or severe movement on these teeth. There has to be a significant amount of periodontal destruction to get that movement. So I think the periodontal disease index and the tooth mobility index do kind of work together hand in glove.

So, how do we manage these lastoma and periodontal disease? Well, it's very challenging, and as I said, I like to use the phrase management because I don't think we can treat them massively successfully. I think we can manage them.

Usually I can improve the periodontal case one or two grades generally, but it requires both local and systemic treatment. It's based around removing teeth from occlusion, where required, reducing transverse ridges that can wedge food into these interdental spaces like what we call a piston effect. You want to flush and remove food material from these in proximal spaces, sometimes pack.

You know bridging of kits, sometimes with paraceuticals is, is warranted, and, and widening can be effective for some cases, but I do think you need to select these quite carefully because that's the widening when done inappropriately and without care can have some quite catastrophic effects. So Neil Townsend and. Another diplomat in in equine veterinary dentistry looked at whether flushing and packing is adequate for diastomata treatment.

OK. And what he concluded is there's little peer reviewed evidence on the treatment of equine diastomata full stop at the moment. OK.

There's just some images of the mine here with, with some diastomas here. So this one here you can see is because there's a displacement. OK, again, there's some, some slight, displacement of tooth here to.

Get the food packing in the proximal space here. And, and what I just wanted to show you on this image here is, is this diastomata isn't perpendicular to the line of cheek teeth, and, and it's very close to the pulp horns here. So you can see, you know, inappropriate diastoma widening here without the the right training and the right instrumentation is highly likely to expose some sensitive structures here in that teeth if you haven't got your wits about you when you're doing it.

So, just moving on to Malausian correction and, and this is obviously the cornerstone of equine dentistry. So any of you out there day in day out doing teeth, you know, this is the cornerstone of what you're doing and it's essential for oral health and comfort in my mind, and there's many methods and many techniques and ways to skin a cat on, on how to do good. Dentistry, occlusal equilibration, if you've been trained in the states at all or anything like that.

And there's many types of instrumentation to do this, and there's hands versus motorised and, and that debate has been been raging for many, many years, but I think it would be fair to say that most people doing a significant amount of Eco dentistry in modern practise are doing the majority of their work with motorised instruments now. And that's not to say you can't do a very good job with hand instruments, but with the volume of work we're doing the stuff now, most of it are using motorised instruments. And obviously, these are some of the focal overgrowths in these images here that you'll all be very familiar with.

OK. So if we are using motorised instruments the majority of the time, Rob Pascoe, another diplomat in, in equine inventory dentistry, raised the question, does thermal injury affect teeth during dentistry? And basically what he's looking at here is, is with the temperature rises that we can affect with motorised dentistry, should we be worried about this?

And this paper looked at some of the historical peer reviewed literature on this, and basically talked about that temperature rises of less than 2.2 degrees Cel didn't produce any histological evidence of damage to puls tissues based on the Zach and Cohen paper of 1965. And this is the kind of seminal paper which also showed that temperature rises of greater than 5.5 degrees resulted in pulp necrosis in 15% of the teeth.

I think we can all agree that that's bad. I don't think, you know, saying there's a 15% chance that you can kill a tooth by, by heating up is acceptable. But you do have to bear in mind that this paper looked at primate teeth, so monkeys, and they're bracket on teeth, and that is very different to hit on teeth.

OK. And these increased pulpable temperature can be produced through the use of motorised instruments, that's, that's been established, and, and that measured temperature increases of up to, you know, over 24 °C in one site have been noted in, in researching this, and that larger diameter discs were found to increase the likelihood of reaching a. Critical temperature by eightfold because of the rotation and the distance that those larger discs are spinning in, and the doubling rotation speed resulted in a reduction in the time needed to reach critical temperatures by 52% in maxillary teeth and by nearly 80% in mandibular teeth.

So you want smaller discs rotating at slower speeds to try to keep the temperature down and that an increase. Pulp temperature of 1 degree C continued after you stopped grinding, so you can, you can work on a whole teeth and then stop, and that tooth would increase by another degree once you'd stopped doing. And the length of time on a teeth for a cool for a tooth to cool back down after, was about 5 minutes in a younger horse and 10 minutes in an older horse, and there was some postulation that was due to the amount of blood flow that goes through a younger tooth than an older tooth.

But water cooling is good. Intermittent water cooling reduces increases in temperature and continuous water cooling prevented any significant temperature increase, OK. But water cooling following a reduction of tooth was found to be protective, and increases both secondary denting was also protective, and we know there are quite large variations in the depth of secondary denting based on some previous literature.

And I just wanted to include these pictures here of the little adon adontoblast processes coming out of the tubules here and then this next picture. And when you're thinking about maloclusion correction and reducing dental overgrowth and stuff, just always have this picture in your mind and that you can do harm to the dentin, and it's linked to these odontoblast processes and it is a vital living structure. And again, these are some images from the papers about secondary dentity.

I talked about in another lovely anatomical illustration by Cartenta here that just show, you know, how available the pulp is to the occlusal surface of these teeth and just bear this in mind. I also think this image is very interesting to show that #4 pulporn isn't actually linked to the greater pulp network in this, and this does beg the question. With some people in this day and age that are advocating root canal therapies in sheep teeth, well, how would you ever root canal?

That pulp horn there when it isn't connected to the rest, so, so that's just something to bear in mind as well. Stoke conclusions, there's a likely that uncalled motorised instruments causes significant heating of dental tissues, and the consequences of this heating remains unestablished in a clinical scenario, but it's likely to cause thermal trauma. And as far as I know, there are just two main suppliers out there, HD and Derson that at the moment.

Sell water cooled hand pieces out there, so they're just people to maybe just think about and keep in mind if you are wanting to buy a new bit of kit and I think really we should be moving in that direction. So just quickly moving on to minimally invasive dental surgery, I know I'm getting near to the end of the hour now, so I'll try and just go through these reasonably quickly. It was basically the development of less invasive techniques for the extraction of, of cheek teeth and primarily fraction cheek teeth.

And they fall into two main categories, ste and pin or minimally invasive repulsion, and then minimally invasive trans buckle or minimally invasive trans buckle screw extractions, OK? And this reduced the complications that we used to see with traditional repulsions significantly, and a complication rate of only 26% of horses undergoing MTE was noted in a recent paper by 10. DSL and and 81% of the time it was successful MTE with a complication rate of only 16% in the previous paper by Lang and Hart in 2015.

And over 90% of these MTE procedures were able to be performed in the standing stated horse, which echoes what I was saying about the use of constant rate infusions and regional nerve blocks earlier. So this is minimally invasive repulsion and some images just from Frank Stellenberg, that I, I borrowed from him just to show how very small fine repulsion pin can be used just to repulse teeth in, in some images. Here's another image from Frank just showing a maxillary repulsion with a very small pin just going through a a fisture on the top of the face to try and repulse the tooth.

And again, equine Blaze Direct, which is a good, very good equine, dental company in this country, they do a very nice MIR kit that is, you can just buy straight off the shelf and use, and it, it's very useful. There's a sharp one to, to make your incision and then a, a flat base punch just to try and renew the fractured tooth or dental remnant or whatever it is you're trying to get. So moving on to MTE, this is a lovely MTE kit made by Pegasus 4D in Germany, and it's a company run by Frank Stellenbosch.

It, it's made my life so much less stressful, so, you know, you can get these, these fractured teeth out in a far less aggressive way, . There are some very real risks with going through the tree though and going trap and Buckley, and I think you do need some further training and a good understanding of the, the buckle anatomy to undertake this procedure. So I'd encourage everyone to go on the course that's run on this and to do some further training if this is something that you're thinking of undertaking before and buying the kit.

You need to have a good understanding of the anatomy, you need to be careful about where you're going to put your incision and your local before you put your incision. OK, and then you can obviously put your trocar through the cheek. Take some radiograph images to make sure that your alignment and your and your setting of your instrumentation is right.

And then once you've drilled your hole, you can then tap your hole and then insert your pin and hopefully if you've managed to loosen the tooth with good elevation, either pre or post the MTE you can then extract the tooth successfully. And, and you then start to get the tooth rising, and then you can extract the, the apical remnant as required. And again, Thankful again to Justine who let me steal a video cos mine all went AWOL and this is just a short image showing a dis distomolar supernumerary just being just being moved by an MTE here and out she comes.

So just very quickly, just to touch on the end. TMJ disease. In my opinion, there's a lot of, what should I say, bobbins talks about.

TMJ disease and pathologies and stuff. And I think to start with those people that are trying to talk about the TMJ need to have a slightly better understanding of how the joint functions and the anatomy involved, and these are just some lovely images showing the, the, the diodal nature and the disc in the middle of the TMJ joint. And again, a, a recent critic clearra topic by Tom Whittle from the RBC.

See show that there's no definitive evidence of TMJ disease in the horse, because this, all the evidence is pretty anecdotal and pretty limited. We do have some good evidence that the diagnostic approaches to blocking the joint and stuff are pretty sound, and there's really good evidence for the images, the benefits of imaging, the TMJ by radiography, nuclear sintigraphy, computer tomography and ultrasonography. Here's a really nice CT image showing your cheek teeth.

But. Do just bear this in mind, because experimental evidence regarding cytokine response in the TMJ indicates that this joint may show different dynamics to other joints, and that dental pathology has always been postulated as a cause of TMJ disorders or diseases, and, but a recent study showed that, you know, pro-inflammatory cy. Time concentrations did not correlate with age or dental pathology score in a in a study by Calm out in 2006, so there isn't a clear cause and effect there, and I've just zoomed in on this CT image here just to say, a lot of the horses that go for head CTs for other dental regions have.

Subchondral TMJ cysts, and in my hands anyway, they are very rarely clinically significant. So just so you see these subchondral bone cysts in the TMJ's on CT scans, doesn't mean that they're, they're clinically relevant. So I would encourage people to, to do analgesia to prove that they are a source of discomfort or pain if, if you're thinking of things like surgery or medicating this joint.

So that's me got to the end and as Sophie said, we'll be I'll be happy to take some questions and some answers, now at the end, if any of those have come in. Just a, a quick shout out to where I work at Paul House Equine Clinic. We're lucky that about 24 months ago we just opened a new 2.4 million pounds referral clinic, .

And it's actually opened by His Royal Highness Prince Charles, so this isn't me boring Prince Charles to death about equine dentistry, as you can see he looks thrilled, and just to show we've got the normal gambit of, of surgical and medical referral things and MRI and things like that. I'd obviously like to, thank the webinar vet for kindly inviting me to speak this evening and for Bailey's Horse Feeds who have kindly sponsored, this webinar. I'm a big fan of Bailey's Horse Feed, high fibre nuggets.

They're quite big fibre nuggets, but if you soak those down in warm water, I find that's the perfect post-surgery dental feed for my dental cases when they're in the, in the hospital and works really well. Just to acknowledge my secondary affiliations, I work for Pool House Equi clinic, but we're now part of IBC Evidencia and part of their, referrals network. I'm also a diplomat and a member of the Educational Committee of the European Veterinary.

College, I'm an advanced practitioner, examiner for the Royal College of Veterinary Surgeons. I'm a committee member for the British Veterinary Dental Association, and I'm a member of the governance Committee for Dentistry for both Beaver and the BABT and I've got no consultancies for any of the commercial companies that I mentioned in tonight's proceedings, and I've got no funding grants or anything for doing this webinar and all the cases that were presented in this presentation we got owner consent form. So thank you very much for your, listening to me tonight, and I hope you will manage to stay safe and look after yourselves and your families in, in what's going on out in the world at the moment.