Jim Berry: [00:00:00] Welcome to the WSAVA podcast. Today's discussion focuses on advanced dental procedures and the options available when treatment goes beyond routine care. As you listen, consider this, how do you decide when to pursue advanced dental interventions? Our interviewer, Jon Tam, speaks first with Kevin Ng and later with Cedric Tutt. Let's listen in. Kevin Ng: Hi Jonathan. Jon Tam: Hi Kevin. We're happy to have you in our interview to talk about periodontal and endodontic disease and how we can save the teeth. First of all, we should talk about what periodontal disease and endodontic disease are and, as I know like, periodontal disease is probably the most common disease in dogs and cats, and endodontic disease is also quite common in animals, but quite often they got under diagnosed, would you mind sharing like what they are and how common they are? Kevin Ng: Thank you for having me, Jonathan. So I think that, not just [00:01:00] periodontal and endodontic disease, but essentially oral pathology in quite a few variations is very common. I think that we like to focus on gum disease, or periodontal disease as it's more officially known, because it is one of the most common oral conditions in dogs as well. Studies have shown that up to 70% of cats, 80% of dogs have periodontal disease and we also know that periodontal disease tends to become more common, not just as the patient ages, but in dogs at least, as the patient gets smaller in size as well. So gum disease is more common in smaller and older dogs. If you've got an older, smaller dog, it's likely they'll have gum disease. In my experience, almost every patient I examine has some level of periodontal or gum disease. Let's just focus a little bit on gum disease for the time being, and we'll talk about endodontic disease a little bit later. Periodontal disease is, [00:02:00] it's a little bit complex, like it's not, not a disease in terms of fulfilling like koch's postulates in that you've got an infectious agent that comes along, infects an animal and then they get disease and then the moment you get rid of that infectious agent like a virus or, or a certain bacteria for example, the disease goes away. It doesn't quite work like that. So what starts it all off is it starts as proteins in your saliva as well as from your food attaching to the surfaces of your teeth, and that's called the salivary pellicle, bacteria love proteins. It's one of the things that they consume in order to generate food, in order to, to multiply. So what happens is that the bacteria from the mouth and from the environment, they attach to proteins on the surface of the teeth, and then they start to multiply. When this first happens, the bacteria tend to be cocci, they tend to be more what we call commensal bacteria, which are bacteria that live normally inside your mouth. But as the layer of bacteria [00:03:00] gets thicker, then what happens is that it changes the environment. As that layer of bacteria gets thicker, then you start to form what we call an anaerobic environment, which is where there's less oxygen, and that allows more aggressive bacteria or more pathogenic bacteria, such as rods, spirochetes, and gram-negative bacteria in order to multiply. These bacterias are the ones that kind of produce inflammatory mediators as well as chemicals that can insult the gum tissue that surrounds the tooth itself. So periodontal disease as it progresses, these bacteria cause inflammation of the gums, and inflammation is a host or an animal's normal response to those bacteria, and it causes inflammation. Now, if we don't get rid of that bacteria, what ends up happening is that inflammation gets severe enough to damage the structure surrounding the tooth, not just the gum tissue, but the other components of [00:04:00] what we call the periodontium, the supporting structures of the tooth, and these include things like the cementum, which is the outer surface of the root of the tooth itself, the alveolar bone, which is the bone in the jaws that supports the tooth, as well as the periodontal ligament, which actually attaches the tooth to the surface of the bone. Now, when we have enough inflammation for long enough, these structures get irreversibly damaged and go from gingivitis to periodontitis, which is the irreversible stage of gum disease. Jon Tam: It seems to be complicated disease and I, I've seen there's still a lot of things that we don't know about  periodontal disease, even with the newest technologies. And it also explains why brushing your teeth is very important because it happens with removing all these particles and pathogenic bacteria. Is that right? Kevin Ng: So brushing and removal of these what we call dental deposits. So dental deposits, like the layer of bacteria is called plaque. Given it enough time, that hardens into something called [00:05:00] calculus. Toothbrushing is good at removing plaque, but calculus is mineralised, so it's hard. That mineralization comes from calcium, phosphorus in the saliva and other minerals in the saliva itself. So once it hardens, it's quite attached to the tooth surface itself, and we find that toothbrushing is no longer effective, and we have to be a little bit more proactive in trying to remove that dental deposit. Once we start to see that hardened deposit develop on the tooth surface. We really need a professional periodontal treatment. Also, some people also call it a COHAT. Some people also call it a professional cleaning or scaling to actually remove those deposits. Jon Tam: So talking about COHAT. So not only does it look for periodontic disease, but we also investigate into a disease like endodontic disease. Would you mind like telling us about like how common endodontic disease is in animals? Kevin Ng: So, COHAT stands for Comprehensive Oral Health Assessment and Treatment. It's just a system of [00:06:00] examinations and procedures in order to make sure that we have a complete oral examination. So the other thing that COHATs will often identify is they'll often identify what we call endodontic disease. So the tooth is a hollow system filled with blood vessels, nerves, connective tissue, and important cells vital to the function of a living tooth. The endodontic system is like a straw, and whenever we have a fracture of a tooth surface, you are opening up one end of the straw and the other end of the straw is actually buried in your jaw bone. So if you have an open tube that leads into your jawbone, that bacteria that are, that live inside your mouth, can actually migrate into that hollow tissue and then make its way down into the bone. And then going beyond that, the jaw bone, or in some cases the periodontal ligament or the periodontium of the tooth is what we call endodontic disease. It's pretty common. Jon Tam: That's very common and so it seems it's also quite under diagnosed in terms of [00:07:00] how often we general practitioners find them. So what are some of the most common misconceptions gps have about periodontal and  endodontic disease and saving damage teeth through these treatments? Kevin Ng: I'm glad you asked that because this is all an area I'm particularly passionate about. One of the most common things with general practitioners is not so much that they have misconceptions, but that we could definitely teach them more. There is so much to learn. When I was a general practitioner at 15 20 years ago, extraction was the only option that I was well aware of. And whenever I had a tooth presented with a dog that had periodontal or endodontic disease, I would extract those teeth. As I became more educated, I realised if theres endodontic disease, we could do a root canal or vital pulp therapy, endodontic treatments, even if the tooth is minimally fractured, like in some cases there are steps that we can perform to minimise irritation to that tooth. Jon Tam: So would you mind sharing what's your overall philosophy on saving teeth versus [00:08:00] extraction and how that decision impacts the animal's quality of life? Kevin Ng: I'm in the business of saving teeth. If there is an option to preserve a tooth for function, in some cases, the presence of the tooth is really important for that dog's use, say for example police dogs or military dogs, like the function of a canine tooth is really important for their job. And not just that, but a lot of our clients these days have dogs that go to shows and the loss of a small tooth can play a big role in their ability to work and interact with their owners. I like to preserve teeth. But don't just try to save every single tooth. There are so many factors that I take into account as well. I take into account what's the cost of the procedure, not just the monetary cost as well. How many anaesthetics does the dog need to go on? Some of our procedures, yes, we can do them in a single sitting, but some of them might need to be staged. And then how healthy is the dog or the cat? What is their overall health status? Do they have any underlying health [00:09:00] problems? Let us see how long we can afford to anaesthetize this patient for. I also take into account the client's ability to come back for follow-up. Are they willing to take another x-ray, for example? Are they willing to brush their dog's teeth on a regular basis? Because if the dog has poor husbandry at home, we can invest in trying to save these teeth. But if the client is unable to, for whatever reason, perform requisite home care. I don't want to waste the client's money. I don't want to put a dog under anaesthesia unnecessarily. I take into account all of these things. I cater my treatment recommendations to the patient. I also cater them to the client itself, and I like to have a really frank discussion with my clients as to what's the best for Fluffy or Ginger, but also what's the best for your situation at home. Jon Tam: What do you do to make sure the owner is doing enough active home care, and how do you monitor regular for the periodontal [00:10:00] condition? Kevin Ng: I'll answer your question in two parts. I think you asked initially about how do I monitor the client's ability to perform home care and their level of home care. That's where history taking comes in. I'll have a detailed discussion with my clients and I'll ask them, what do you do to keep your dogs teeth clean? How often do you present to your regular vet to have a periodontal treatment or a clean? We ask them all of these questions, and then after we recommend treatment options, part of that conversation is how much home care will you be willing to do? And the clients where they are willing to do the home care, I say to them, why don't we consider trying to save this tooth with an advanced procedure? Because it sounds as if you are really committed to providing the necessary care, increasing our chances of success. To answer the second part of your question, how do we determine what to do with each particular tooth? I treat each of the teeth in a dog or cat's mouth, or any animal's mouth for that matter, as if it were its own patient. We measure periodontal probing depths. We take intraoral radiographs. [00:11:00] We perform a complete oral examination, the outside of the patient's head all the way through to the back of their throat. We take six periodontal probing measurements around each tooth. We use a dental explorer to examine for cavities to examine for pulp exposure, to examine for tooth resorption. We examine all the surfaces of their mucus membrane, so that would be the tongue inside of their lips, like the mucus cutaneous junction, like their tonsils. We examine all of these things and then we list down a summary of findings for each tooth for periodontal disease. We measure the amount of bone supporting the tooth as a factor of its root length, right? So normal is what we would consider to be a hundred percent of root length, and then you've got various increasing severity. So mild periodontitis would be loss of bony support up to 25%, moderate 25 to 50, and severe greater than 50%. We also measure pocket depths. Because we don't just want to look at this as a fraction of [00:12:00] bone support. We also wanna measure how deep the pockets are because the deeper the pocket, the harder to maintain. Toothbrush bristle can only clean a pocket up to five millimetres. A professional clean can only clean up to five millimetres deep. Anything more than that has a poor prognosis for the tooth. For endodontic disease, we look at the amount of the tooth that's been damaged. Is the pulp exposed? If the pulp is exposed, the tooth really needs treatment. We're talking either a root canal or an extraction and if the pulp isn't exposed, we take a radiograph to figure out if the tooth is still alive because there are some cases, and this is one of those points where I'm going to harp on a little about the importance of dental radiographs, even if the pulp isn't exposed, the tooth can still die. We take a radiograph and look at the endodontic system, we look at the underlying bone. Is there any evidence that the tooth has died, as in the pulp is abnormally wide? Is there any evidence of a [00:13:00] periapical pathology inflammation around the root of the tooth? Some people call it an abscess. It's not really an abscess. Oftentimes it's a granuloma. Sometimes it can be a cyst, rarely an abscess. That's why we call it periapical pathology, and that's why you'll see me avoid the use of the term tooth root abscess. So we'll assess the inside of the tooth. The other thing I ask is, when did the fracture happen? If the fracture happened within 48 hours, then we can do what's called the vital pulp therapy, which is where I remove the infected portion of the pulp, typically about five millimetres, and I put down the layer of medication onto the surface of that pulp and then I'll restore it. And that procedure has a success rate of around about 85% and when I say success rate, that's the ability to keep that tooth living, to keep that tooth alive, to keep the tooth functional for a vital pulp therapy. If the fracture is greater than 48 hours old, the likelihood of a vital pulp therapy succeeding is not great, will perform what we call a root canal treatment. And we can only do this if the tooth is old enough. [00:14:00] Typically after about one year of age in both dogs and cats, a root canal treatment involves removing the entirety of the pulp cavity. Oftentimes it's necrotic or infected. We remove it, we sterilise it completely, and believe it or not, we use sodium hypochlorite, also known as bleach. We obviously use lower concentrations typically around somewhere between 2 to 6%, thereabouts. So we sterilise the inside because what we wanna do is we wanna kill that bacteria. After we kill the bacteria, we need to prevent bacteria from getting back into that potential space. So we fill the pulp cavity with a combination of gutta-percha and a sealant. Gutta-percha is plant derived. It liquefies slightly when it's warm, so it allows us to fill all the spaces within that pulp cavity and then we put a filling on top of that. And if, say for example, it's a working dog, or it's a dog that's prone to chewing on something, the other thing we can do is we can actually put a metal crown on the outside of the tooth to provide some form of abrasion [00:15:00] resistance. Now that adds additional cost, but in those patients where the abrasion is a risk, I say to my clients that we wanna protect our investment. Jon Tam: So I guess the good thing about us being a dentist is we can do things from the lower invasiveness to the most invasive surgery if needed. Let's talk a little bit more about endodontic disease. How do we advise our pet owners to prevent endodontic disease in dogs and cats? Kevin Ng: What I usually recommend is managing their chewing behaviour. Chewing is a dog centric behaviour. I generally try to avoid bones. If you're gonna give a dog something to chew for their oral health, I usually say to my clients, look like I use the products from the Veterinary Oral Health Council. If you're looking for environmental enrichment, then there are a lot of food puzzles that are available now. Hence, if you're playing fetch, play fetch with a, a rubber ball. I avoid tennis balls and the reason is that tennis balls have an abrasive [00:16:00] nylon surface and given enough time that can actually wear down a tooth surface. Jon Tam: So what about cats? Kevin Ng: I love cats when they are comfortable, they're very friendly, they're very affectionate. They are some of my favourite patients. They are less aggressive chewers and they don't have that same drive to chew as dogs do. Yeah, I think that there are some products by the VOHC they can chew on. We do see cats with fractured teeth, usually the canine teeth, oftentimes this is from fighting. Oftentimes it's traumatic, and I'm not sure where they fracture their teeth on, but in Australia, we are moving towards keeping cats indoors. We have catios or cat runs, which are outdoor enclosed areas. These help protect cats from altercations. That's my strategy for preventing endodontic disease in cats. Jim Berry: After Kevin Ng, Jon Tam is joined by Cedric Tutt to continue this conversation. Jon Tam: Welcome Dr Cedric Tutt. Cedric Tutt: Thanks for the welcome, Jonathan. Jon Tam: To start with, maybe we can start with talking about like the definition of [00:17:00] prosthodontic treatments and maybe we can also talk about how those treatments in animals are different from human beings. Dr Tutt, would you mind telling us more about what actually is for prosthodontics treatments? Cedric Tutt: Yeah, sure. So prosthodontics is the field of dentistry, dealing with maintenance of functional teeth, and this might mean restorations or replacement of missing or damaged teeth. It involves the use of manufactured devices and implants placed in the jaw onto which prosthetic teeth can be attached. So if we look at prostheses, they include crowns, bridges, and implants. Today we're going to concentrate mainly on crowns and implants. Bridges can either be attached to one tooth and then have a cantilever where there's no tooth supporting it underneath or to two teeth, one in front, and one at the back and then we have a prosthesis in between the two. If we think about dentures [00:18:00] and animals, it's not actually a practical option in animals, mainly because the severe biting forces that animals have. And secondly, that these devices become dislodged, and if they become dislodged, they can cause some distress to the animal because it might prevent them from closing their mouth. Jon Tam: Where would you recommend prosthodontics restorations, such as crowns? And what key factors should a vet consider before proceeding? Cedric Tutt: In animals, the teeth are either conical or triangular shaped. Now, if we want to have retention, when we do a crown prep, we need the convergence angle to be less than 20 degrees. If the convergence angle is less than 20 degrees, we're going to get a very good physical fit and there'll be some physical retention. If the convergence angle is more than that, and it commonly is in the animal's we treat, we rely more on adhesive or cement to keep the crown in place rather than physical retention. There are different crowns [00:19:00] that can be placed and the crown preparation is going to be determined by the crown that we intend placing in the mouth. If we think of porcelain or a metal crown, that is a very thick structure. Then porcelain metal is usually gonna be put onto a crown prep that involves a shoulder and quite a substantial amount of tooth needs to be cut away to place that crown in in place. What we are finding in animals is that cutting away so much tooth to get maybe a little bit more retention or put a thicker crown on the tooth itself, we're going to end up weakening the tooth. In animals we prefer two techniques, the chamfer technique and the feather edge or the knife edge technique. Both have minimal removal of enamel. Yes, it does involve removing some of the enamel to get a good margin and some retention, but it doesn't go deep into the dentine. If we think about the carnivores that we treat mainly dogs, because yes, we do put crowns on cats, but intermittently, we [00:20:00] mainly put crowns on dogs and dogs have the canine third incisor interlock, which means that if we are going to put a, a prosthesis on any of those canines, we need to be sure that the prosthesis doesn't interfere with occlusion. So we need to be sure that the interlock is something that we can maintain after the crown is put on. In carnivores, we have carnassial teeth that work like scissors. Again, we need to be sure that the shape of the crown that we're gonna put onto the carnassial is such that we can restore that scissor function and we need be sure that the animal can close the mouth and without it interfering. So some veterinarians who have a lot of experience doing the crowns will be more likely to advise a client that they should have crowns put in the animals then veterinarians who use crowns infrequently. So I think that there's a lot of personal decision involved in whether we convince the client the animal needs a crown. If we look at crowns [00:21:00] in working dogs, we can place crowns to give the animal a longer working life. However, if we make the prosthetic crown as long as the original crown was, they're going to be leverage effects so the chance of fracturing the crown off right at the gum level are increased. So we need to be sure that if we are going to place these crowns, people understand that the working behaviour has to change.  Carnassial teeth, maxillary  carnassial, benefit from the crowns placed on them. When those teeth are fractured, often there's a slab fracture that happens, and those slab fractures can extend subgingivally, which means that the tooth bulge is no longer there to protect the gingiva from food that's been chewed. By placing a crown on the tooth, we recreate the tooth bulge, and that moves the food away from the surface of the gingiva rather than it being impacted into the gingiva. Normally, we would suggest that in the carnassial teeth, once root canal treatment is successful one can consider putting a crown on it. It's not wise to tell the client the [00:22:00] crown should be put on immediately after root canal treatment because often those root canal treatments fail. If we are going to choose a tooth that is going to have a crown placed on it, we need to be sure that it is a peridontically sound tooth. Also, if an animal has stereotypic behaviour, the animal needs to be unlearned of that behaviour before we put a crown on because if you don't unlearn the behaviour, the risk of it carrying on and doing the same thing is gonna be much greater. Jon Tam: Would you mind further elaborating on the steps for doing crown impression, propagation and cementation? Cedric Tutt: Crown preparation can be done in a number of ways. What I prefer to do is, once I've cut the crown, is to take some hard body material and make an impression of it, and then examine that impression is actually negative of the tooth surface. By looking at that, I can see if my margin is correct and distinct all the way around, and I can check the angles of the walls as well, and the convergence. So we'd start off by taking an impression of the tooth and the adjacent teeth. Then cut [00:23:00] away some hard body material and then place a wash or a light body material in that area and then place it back on the tooth. That's going to give us a good definition of our crown prep, and that's what the laboratory is then going to place the manufacture of the crown on. We also need to take a full mouth set of impressions. We take a a rigid tray, put the poly vinyl siloxane in the rigid tray, and then take an impression of the upper and lower jaw and finally do a bite registration. Our bite registration can be achieved either by using wax, so we take a wax sheet, which is softened, and we place that between the teeth and then close the mouth. Or we prefer to use poly siloxane for that as well. So we take a sausage of polyvinyl siloxane and we will then put it onto the maxillary teeth and then close the jaw so that the mandibular teeth place the impression as well. So we have impression of the upper jaw and the lower jaw on one sausage, and that gives us our bite registration. [00:24:00] Now, bite registration is important because in the laboratory, the technician is gonna create some stone models, and those stone models are gonna be placed into a device to check that the occlusion is okay. There is another technique using alginate. Alginate is a powder that is mixed with water, and then it is placed into the impression trays and placed in the mouth, and then when they are set, you're going to remove them and again, send them to the laboratory. However, they are very moisture sensitive, so if they dehydrate, they're going to change their form So be careful how one handles the alginated patients. If we take an alginate impression and it doesn't get to the lab in a good state, we have to have the patient back and take a new impression. So I think spending a little more money on polyvinyl siloxane is probably beneficial. The client would rather pay a little more for those impressions than having the animal anaesthetised again. [00:25:00] Cementation of crowns is dependent on the manufacturer of the crowns. Crown manufacturers will tell us that we need to use specific cements to cement the crowns in place, and these might be chosen from polycarboxylate cements to zinc phosphate cements. They are also resin modified glass ionomers. They are pure glass ionomers. And there are resin based cements as well. For instance, a resin that is placed onto the tooth and into the crown, and the crown is placed in the position and held in position, and then light cured. And then we have dual cure where the cement might be initiated by light and then continue in a chemical cure. Or that can be chemical cure only. So a number of different cements that can be used to cement the crowns in place. Jon Tam: What are your opinions and what are some indications for doing implants? Cedric Tutt: Yeah, so dental implants is going to be a controversial topic amongst veterinarians. [00:26:00] If we think about the indications for implants, why would we want to put an implant in the animal? One reason for doing that is that we'd like to replace a tooth that was lost if it is a working dog. Or there are people who want implants placed in dogs, and I've had a request before where a dog was missing the third molar in the mandible and the client said, my dog was at a show and they marked him down because he's missing the one tooth. And in those situations, I don't do implants. I think it's an unethical thing to do because when the judge looks at it, if you've put an implant in, the judge can say, great. It's got a full dentition. You can breed from it. But we know that some malocclusions and some conditions where animals are missing teeth, for instance, Chinese hairless dog, they're missing teeth because they have an epidermal problem. So if we are going to implant teeth there, they're making the animal look as if it's better than it is. I think it's unethical to do it. In a [00:27:00] working dog, obviously can be done but we need to understand the tooth has a periodontal ligament and that periodontal ligament doesn't only act as nutrition to the tooth, but it also acts as a shock absorber and an indicator to the body as to the amount of force that is applied to it. If you have an implant and you bite extra hard, there's no feedback, and there's a risk that the implant is fractured again. So we need to be careful advocating that we can put implants in the mouth. Most of the time they're not required. We need to be careful of pushing the boundary for aesthetic purposes. Jon Tam: So is there anything we want to say to vets who want to learn dental implantation in animals? Cedric Tutt: Placing implants in animals is a specialist technique and specialists have trained for many years. Some of them, if they've done it full-time, have done it for three years. Part-time, they might have done for six or eight or even 10 years. But those people have a lot of experience and some of them [00:28:00] do implants, but they do it from their specialist knowledge. There's very little written about implants in animals. We need to remember that there are challenges when it comes to doing implants. When we think about our access to diagnostic imaging, we cannot place implants based on radiographs only. We need cone beam CT at best so that we can visualise the jaw. We need to see where the canal is. We need to see the thickness of the jaw and so on. Can we do it? Of course we can. There's no doubt we can do implants, but there's gotta be thorough planning. Implantitis, peri-implantitis will happen if the implant is not taken care of. Jon Tam: So what are some of the ethical concerns for dental implants and how do they align with the WASAVAs welfare centres or global dental guidelines? Cedric Tutt: If we think about the ethics involved with doing implants, if we have an animal that is missing teeth and we are going to place teeth in its mouth, then we are creating something [00:29:00] better than what the animal is. That, to me, is an ethical problem. The fact that the animal needs multiple anaesthesias, some people see that as the ethical problem. If we are considering putting crowns in an animal, that's a minimum of three anaesthesias, one for root canal treatment, one for crown prep, and one for cementation of the crown. The same goes for implants. We need to extract the tooth. We might need to do bone enhancement if pushing the boundary. We need to make sure that bone is gonna be bone that can hold the implant. So we need CBCT images and eventually we need to have a device made. Now I think that most veterinarians who do crowns on a regular basis have gained that experience, and hopefully most of them are only going to use it where ethical considerations have been considered and been found to be not a problem for them to do the procedure itself. I think we need [00:30:00] to remember implants per se are very rarely indicated. However, I must point out that when we speak about implants and veterinary dentistry and jaw surgery, there are implants that are being done for replacing parts of jaws. If you have a tumour in the middle of the mandible and you have to reset from premolar two to premolar four, you can put an implant in there to replace the bone, and you have a bone morphogenic protein, which is added to that, and it's been shown that you can grow a new mandible around the implant. So those type of implants are completely ethical because we are maintaining the occlusion of the animal. We are reducing suffering, we're reducing the drift that might happen that would cause the lower canine to bite into the palate and so on. So using implants to replace parts of the jaw is completely acceptable. But doing implants of teeth only, we need to [00:31:00] look at the guidelines by the WSAVA Dental group. Those guidelines are for the benefit of the animal. We need to be sure that we are abiding by them. Jon Tam: Okay. Thank you, Cedric. To summarise, no matter we are placing anything like a prosthodontic device or like a, an implant, we have to be sure that what we are placing is for benefit of the animals and definitely, for sure, we shouldn't be causing any harm to animals, so we have to be undergoing a lot of considerations before. Explain the procedure to the client and educating the client whether it is necessary. Jim Berry: Thanks for joining us on the WSAVA Podcast where we are transforming care, one episode at a time. We hope today's discussion was helpful. Wherever you are in the world, you'll find more information and further resources on the topics discussed in the show notes and we look forward to sharing our next conversation with you very [00:32:00] soon.