PERIODONTAL DISEASE P2
2013
Attachment loss, as I say, is where you get changes in the gum margin. So, in the top picture, we can see how the root has become exposed of the upper carnassial and post-molar. We can see that there’s no bone between the distal root of the upper carnassial and the first root of the molar. We can also see in the bottom picture how the area between the roots is exposed once again, called furcation exposure.
What’s possibly more of a problem for us is if a periodontal pocket forms because you can’t always see those. Those you need to assess and add an anesthetic. So, in the top picture, that is a periodontal probe that’s been used to examine the whole circumference of the tooth, and probe has been inserted a good 12 millimeters. So, it goes a long way down, and that’s indicating that the ligament of the bone has all been lose around that area, which has enabled me to insert that probe. The problem, as I say, is you cannot see that. You only just take a problem like that under an anesthetic. Also, a client is never going to keep that area clean because no toothbrush is going to go 12 millimeters under the gum margin. So, a tooth like that would need to be extracted.
The bottom picture’s just indicating how teeth get loose. You know, mobility is usually a result of periodontal disease. There are other courses of mobility, and if, for example, you’re examining your mouth and you find a tooth that is loose with no apparent attachment loss if you can’t see gingivitis or you can’t see root exposure or a periodontal pocket, then I would always be suspicious for a root fracture. In general practice, most of the cases that we see are because of attachment loss.
So, this dog, in this day and age, this should never be happening to a mouth. There’s no reason why a dog should be left like this. This doesn’t happen in days or weeks. This is months of accumulation. What we can’t tell by looking at this picture is truly how bad or what the extent of the problem is. The teeth look terrible. We can see a lot of calculus accumulation. We can see a lot of plaque accumulation, but we don’t know what the pocket depths are. We can’t see furcation exposure. So, it’s when that enamel is under and anesthetic that we can fully assess the periodontal status of that patient.
As I’ve said before, a lot of research now is looking at the rate of progression, destruction. Looking at factors, why do some dogs have a huge mouth calculus but actually no deterioration in the actual supporting structures whereas others will get mouth gingivitis or just plaque accumulation on the tooth with gingivitis? Yet, when you probe the mouth, it’s got deep periodontal pockets. So, we’ll look at these individually.
The way I approach periodontitis is I look at areas where there’s going to be increased plaque build-up, and that’s either going to be due to plaque retention or plaque stagnation areas. For example, plaque retention. Calculus would contribute to plaque retention. It’s a much rougher surface so bacteria can accumulate on that surface a lot more readily. Fractured teeth, for example, this picture where you’ve got an abnormal continuity to the tooth or where dentin’s exposed will favor plaque retention. If there are enamel defects on the surface of the surface of the tooth where the enamel hasn’t formed properly, you get a much rougher surface to the tooth. So, that will favor plaque retention and exposed root cementum as you will see in cases of periodontitis. It’s a much rougher area so more plaque is going to accumulate.
Areas of plaque stagnation are areas where plaques are going to get reduced or where plaque’s going to accumulate because it cannot be dislodged, and that we see in cases of tooth crowding or malocclusion, misalignment of teeth, or sometimes where there’s missing teeth. For example, in this picture, the cat has got an extra mandibular premolar. Because they have such a large angle, you’re going to get more plaque accumulation between the teeth, making those teeth more prone to periodontitis. I’m sure you’ve seen this in cases in your own clinics where perhaps you extract an upper carnassial in a dog, and when you go back and look at the dog a few months down the line, there will be more plaque accumulation and perhaps a little bit more gingivitis on the lower molar purely because those teeth aren’t biting against one another, and the plaque is not being disrupted.
Probably the biggest concern for us is a periodontal pocket because periodontal pocket is that area that we don’t see where you’re perhaps getting a 3, 4, 5, in some cases, 12 millimeter pocket, which is area where bacteria can accumulate and be completely undisrupted. So, with a toothbrush, you’re not going to get to them. Eating and chewing is not going to be effective. So, this bacteria can just flourish. So, those are areas of plaque stagnation and also if there’s an abnormal gingival margin. So, for example, if there was gingival hyperplasia like you see in boxes and the gum actually grows over the tooth, it almost creates a false pocket so bacteria can sit under that tissue and disturb.
The important thing always to remember with periodontal disease and I know there is a lot in the Times and the Letter Pages about this, that diet alone is not the cause of periodontitis. You know, it doesn’t matter what you’re feeding an animal, they will get periodontitis. They will get plaque accumulation on the teeth. We know this because wild animals get periodontitis. The difference between wild animals and our pet dog is wild animals have got a much better conformation in most cases. Wild animals also don’t live as long, and we know that adult onset periodontitis is progressive with age. So, a wild dog that may live until 6 or 7 is not going to be the same as Mrs. Jones’s Yorkshire terrier that she’s hoping it will live until it’s 17 or 18 years of age. You know, you’re dealing with completely different disease progression.
We know that raw meaty bones, well some people do advocate them and they can cause more problems. Unfortunately, we see a lot of fractured teeth related to raw meaty bones, and fractured teeth may result in more plaque accumulation. The raw meaty bone people have has no actual study showing that a raw meaty bone diet will reduce the incidence of periodontitis. One study that was done where they looked at feeding dogs and bovine tractors, and it did show that there was a reduction of plaque and gingivitis in the short term, but no long term studies have been done.
One of the quoted statistics that you see is that 75% of cats under a certain age have got periodontitis, and when you reference all that back, it goes back to the Talbot’s study that was done in 1989. You know, when you think of that, those dogs weren’t on very natural diets. They weren’t on a dry kibble. They were probably on taper scraps. So, periodontitis is not a new disease. It’s been around for years and years and years and not the cause of periodontitis. Certainly, diet can be a contributing factor. We know that sticky, soft foods will accelerate plaque accumulation in the mouth, and the ideal can prevent some of the plaque accumulation but it can reduce periodontitis completely.
We also know that plaque is going to form whether food passing through the mouth or not, and you see this in some cat good when you put the feeding chips. If you’re not going the put the feeding chip, you’ll just see how much plaque accumulation occurs on the teeth. Some studies have shown that there’s no difference between the wet food and the dry food, and it all depends on how you interpret all these statistics in cat’s dry food, which tends to be somewhat better but is not clinically relevant. When I mention these dry foods and wet foods, I’m talking about a commercial diet, not a specific dental diet.
Everyone talks self-cleansing mechanism of the tooth, and unfortunately, I think that’s about as significant as a self-cleansing oven. It corrects to a degree, but it’s not the be-all-end-all. Chewing does have an effect in that it encourages salivary production. It encourages tongue movement, and you do get a little bit of dislodgement of plaque, but as I said before, the food and the chew gets deflected away from the gum margin. It’s at that gum margin and the gingival sulcus that you really want to control the bacteria. So, no product is actually going to clean that area. The only thing that works in that area is really a toothbrush.
In some animals with excessive salivary flow, you actually get more calculus accumulation because the tartar or the plaque will mineralize because of minerals in saliva. So, salivary flow can be good for some animals, but in some animals, it is detrimental as well.
Ideally, if we are feeding our dogs, we want them to be on a tough, non-sticky diet. You want maximum tooth contact so it does cleanse the teeth, but we also want them to chew their food to exercise the periodontal ligament and to keep that area stimulated to keep it healthy. At the end of the day, the periodontal ligament is a ligament, and, like any other ligament in the body, if it not’s exercised particularly, you can get some changes. I don’t think there’s any definite studies showing that this is the case, but it makes sense that you want some chewing activity to keep the teeth healthy.
The net thing were going to look at is host response, and this is a big, big thing in a human periodontology at the moment. They’ve looked at various studies, probably at the last five years, and the general though now is that it’s actually host response, rather than the bacteria themselves, that are responsible for the destruction that you get around the tooth. So, the host response.
There’s supposed to be three aspects. One thing is genetics. When we look at our dogs, definitely we see a difference in size and in breed. We all know that Yorkshire terriers, for example, get really bad teeth, and this might be because relatively, they’ve got a much bigger surface area to gum margin compared to a dog like Labradors. This doesn’t fit in with greyhounds though. Greyhounds got a nice mouth. They’ve got long muscles so there’s no overcrowding, but they’ve got very active tissue destruction. So, you can’t always say that the smaller dogs have the worst teeth. We know that certain breeds, for example [24:10] have got very healthy gums whereas dogs, for example Yorkshire terriers or greyhounds get very aggressive periodontal disease.
Things like the general health status are going to influence the rate of destruction of periodontitis, and the reason for that are multiple. If the body covers onto bacteria or the bacterial capsule at the surfaces of the tooth and the gum margin, you’re going to get more active tissue destruction. So, immunocompromised, diabetic animals will be more prone to periodontitis.
The host immune response is possibly one of the biggest factors, at the moment, that people are looking at as the cause of active tissue destruction. What happens is the body feels the bacteria accumulating on the surface of the tooth. Those bacteria release enzymes. They release chemical mediators that trigger inflammatory response. Body is going to respond to that inflammatory response in various ways, and that inflammatory response, once it’s started, is progressive. Some animals will get much worse destruction than others. There’s two things that occur. One is direct entry by the plaque and bacteria themselves. There are certain bacteria that will release toxins that do destroy tissue, but most of the destruction is actually caused by the immune response where the body is releasing enzymes, interleukins that actually cause destruction of the collagen, destruction of the bone. We also know that you get changes in the inflammatory response and you get changes in the body’s DNA that then make that animal more prone to periodontitis. So, once the whole disease has started, there’s no going back, and that’s important because if you can’t go back that means that these cases are a lot of management. You’re never going to cure them. Once again, a cat like this should never be happening. This years of neglect. So ideally we want to get them while they are early gingivitis cases and not to this degree.