Small Dog, Big Smile. How to make sure your little dog has a happy, healthy mouth. Christine Hawke Sydney Pet Dentistry

Transcription

1 Small Dog, Big Smile How to make sure your little dog has a happy, healthy mouth Christine Hawke Sydney Pet Dentistry

2 INTRODUCTION Hello and thanks for downloading my book, Small Dog, Big Smile How to make sure your little dog has a happy, healthy mouth. Small dogs are gorgeous, and deservedly very popular throughout the world. Centuries of careful and selective breeding has provided us with a huge range of small breeds to choose from, each with their own specific characteristics and charm. While good things certainly come in small packages, one of the drawbacks of their small size is that many of these dogs suffer silently from serious dental issues. While all dog breeds are susceptible to teething problems, periodontal infection and orthodontic disorders, dogs with small mouths have the added issue of overcrowded teeth to contend with. Similar to their larger ancestors, they have to find space for 42 teeth, which is sometimes no easy feat. As a result, things don t always go according to plan. My name is Christine Hawke, and I am a veterinarian with almost 20 years experience in small animal practice. After many years in general practice, I developed a passion for all things dental, and have been running a small animal dentistry- only practice in Sydney since I am a Member of the Australian and New Zealand College of Veterinary Scientists in the field of Veterinary Dentistry (this can only be attained through examination), and the American Veterinary Dental Society. I am currently the President of the Australian Veterinary Dental Society, and teach veterinary dentistry to vet students (at The University of Sydney), vets and nurses across Australia. Imagine having a sore mouth and not being able to tell anyone! One of the biggest misconceptions is that dental problems don t need the same treatment in animals as they do in humans. Nothing could be further from the truth! Dogs teeth have the same type of nerve supply in their teeth as we do, so anything that hurts us will hurt them as well. All dogs, whether they are performance dogs or pets, deserve to have a healthy, pain- free mouth. Oral and dental issues frequently go undiagnosed in dogs, partly because the disease is hidden deep inside the mouth, and partly because dogs are so adept at hiding any signs of pain. As a pack animal, they don t want to let the rest of the pack (including us!) know they have a problem, as anything that limits their usefulness to the pack may be grounds for exclusion. This is a survival instinct. 2

3 Dogs will suffer in silence for as long as they can, and they only stop eating when they cannot bear the pain any longer. How to get the most out of this book This book has been written to help you understand how oral and dental problems develop in small dogs, what the implications of these issues are, and what options are available to you and your dog to achieve the best outcomes in terms of overall health, comfort and, if applicable, performance. If you would like to speak to me for advice on your dog, please feel very welcome to call me on Alternatively, you can me on 3

4 TABLE OF CONTENTS WHAT S THE BIG DEAL ABOUT SMALL DOGS? 4 PERIODONTAL DISEASE AND JAW FRACTURE 5 UNERUPTED TEETH 10 UNDERERUPTED TEETH AND PERICORONITIS 13 TRAUMATIC BITE DEVELOPMENT (MALOCCLUSION) 14 PERSISTENT DECIDUOUS (BABY) TEETH 16 SO HOW DO I MAKE SURE MY SMALL DOG HAS A BIG SMILE? 19

5 WHAT S THE BIG DEAL ABOUT SMALL DOGS? Small breed dogs have been selected and bred over many generations to have small heads and jaws, but not necessarily small teeth. In fact, tooth size tends to be more resistant to breeding selection than head or jaw size. While a Chihuahua or Pomeranian obviously has smaller teeth than a Mastiff or a Greyhound, their teeth are relatively huge when the differences in jaw size are taken into account. Therefore they are more prone to overcrowding. Sometimes small jaws and overcrowded teeth may lead to issues affecting performance in the show ring. The bite may become bad with one or more teeth out of alignment, or even a major malocclusion such as reverse scissor bite (or rostral crossbite). However, the consequences of small jaws and crowded teeth are not always purely cosmetic, and can have significant health implications.

6 PERIODONTAL DISEASE AND JAW FRACTURE Dogs with crowded teeth are much more prone to periodontal disease than those with roomier mouths. Periodontal disease is an inflammation of the gingiva (gums) and deeper supporting structures of the tooth (ligaments and bony socket), caused by the buildup of plaque bacteria on and around the tooth. Natural tooth cleaning mechanisms that assist in controlling plaque accumulation include chewing (mechanical removal of plaque deposits by abrasion) and saliva flow (flushing action and antibacterial components, including immune compounds and enzymes). Both of these processes are far less effective if teeth are crowded together, rotated or overlapping. Even our best human efforts to keep overcrowded teeth clean, such as tooth- brushing or use of antiseptic rinses or gels, can be rendered ineffective as many of the tooth surfaces are just too difficult to access. In humans, flossing between teeth can help, but few dogs will tolerate this!! Overcrowded, rotated teeth with advanced periodontal disease in a two year old Japanese Chin (left). Despite the young age of the dog, the canine and all four premolars required extraction. Left undisturbed, these bacteria multiply and spread below the gum margin, causing gingivitis (gum inflammation and bleeding) and eventually destroying the jawbone itself. Bacterial spread into the underlying bone is further enhanced when teeth are crowded together, as the lack of space prevents the gum from forming a seal around each tooth. With no effective barrier between overcrowded teeth, irreversible damage to the deep structures of the jaw rapidly follows. Crowded teeth without a gingival seal between the teeth (arrow). Bacteria can easily invade the jawbone between these teeth as there is no effective barrier.

7 While early loss of teeth is the most common final outcome of severe periodontal disease, far more serious issues can also occur, including infection of the sinuses, oral fistulas penetrating into the nasal cavity, and even broken jaws! The lower jaw is particularly susceptible to fracture in small breed dogs, as it is relatively small and the tooth roots often extend right through almost the entire thickness of the bone. Dental xray of a 2.5 kg Maltese terrier X (left). Severe bone loss is occurring around all teeth, with the overcrowded tooth crowns providing areas for bacteria to collect and head down into the deeper structures. The mesial root of this oversized lower carnassial tooth (the left root of the biggest tooth) extends right down to within about a millimetre of the lower edge of the jaw. The root has developed with a big bend in it as it ran out of space to grow. Overcrowded teeth in a 6kg terrier (right, top picture). Plaque and tartar can build up in between these teeth (arrow), which have no gum barrier between them to prevent bacteria from entering the jawbone. A dental xray (right, bottom picture) shows the extent of the bone loss between these two overcrowded teeth. A probe confirmed that this pocket was 1cm deep a lot for a small dog, and on track for a fractured jaw in left untreated. The tooth was extracted to prevent further bone loss and allow the infection to heal. 6

8 Jaw fracture in a 12 year old Australian terrier with severe periodontal disease. Chronic infection weakened the bone to the point where it snapped when she bumped her face coming down the stairs. Damage caused by chronic periodontal disease can severely weaken the jaw - enough for it to snap with only minor pressure (such as catching a ball, or bumping into a wall or doorway). Finally, bacteria can easily gain access to the bloodstream when the gingival attachment is weak or damaged, spreading to the rest of the body, including the liver, heart and kidneys. In humans there is a well- documented association between periodontal disease and illnesses such as heart attack, stroke and premature birth in humans. In dogs, heart, liver and kidney pathology has been reported to be associated with periodontal disease. What can we do about the risk of periodontal disease in small dogs? All dogs, large or small, should have a good oral hygiene program to control plaque and tartar buildup. This should be started from a young age, and can include varying combinations of tooth brushing (by far the most effective method this is why OUR dentists recommend it!), chewing using effective dental diets and chews, and chemical disinfectants designed for use in pets. For more information, including tips for introducing tooth brushing, check out 7

9 For dogs with overcrowded teeth, early intervention can reduce the risks and make it easier for the teeth to be kept in good condition. The best treatment plan for each individual dog depends on which teeth are involved, and what the plans are for the dog (eg performance vs pet). Orthodontic movement and and selective extraction are a couple of options to consider. Orthodontic treatment may help move the teeth into a better position, and may be the preferred option for dogs that need all of their teeth eg for working or showing. Remember that orthodontics can be complicated, and may not actually create more space if crowding is severe. Each tooth also has a large root hidden below the gum level, so the degree of crowding may be even worse down there than it appears on the surface, limiting orthodontic options. Orthodontic movement of teeth also has serious ethical considerations for showing or breeding dogs, so it is strongly advised that you discuss this with a vet who is well informed of the restrictions on, and ramifications of, this treatment method. For further advice, you can also call me on Selective extraction of teeth can reduce the risk of oral infection, and increase the likelihood that major teeth will remain healthy and functional for the many years our modern pets now live. The decision to remove one or more teeth, and which teeth to remove, is based on several factors, including the: position of the tooth (eg a tooth that is severely out of alignment vs one that is in the correct position) importance of each tooth (eg a large carnassial or canine vs a small premolar) health status of each tooth (eg a tooth which is damaged or already has significant periodontal disease vs a healthy tooth) Severe bone loss Crowded teeth Crowding between the large first molar (right) and the smaller second molar (left) has resulted in severe periodontal disease affecting both teeth. Had the smaller tooth been removed earlier, the larger tooth may have been kept healthy and saved. The thought of extracting teeth, particularly healthy teeth, to prevent future extractions may sound counterintuitive. However, in the long run, selective extractions can save more teeth than not doing anything, as the remaining teeth are less prone to infection and disease. For example, it can be better to lose one small lower incisor and save the neighbouring canine, than to lose both down the track! 8

10 Of course, extractions are not always an option, especially in show animals. The alternative is meticulous plaque control, using home hygiene methods such as toothbrushing, appropriate chewing and oral disinfectants. Regular scaling and polishing under general anaesthesia to remove plaque and calculus that can t be controlled by these methods is also required. 9

11 UNERUPTED TEETH Unerupted teeth can be a serious issue! Pups may have missing deciduous (baby) teeth, permanent (adult) teeth, or both. When a tooth is missing and has never been present, the possibilities are: 1) There is no tooth present at all (congenitally missing) this may be a genetic trait in some breeds, including many of the smaller breeds 2) There is a tooth present but it is having trouble erupting overcrowded mouths are especially predisposed to as there isn t much room for error and neighbouring teeth can block the eruption pathway A congenitally missing deciduous tooth almost always means that there will also be no adult tooth in that position (this is because the adult tooth buds develop from the deciduous tooth buds during gestation) 1. Not all congenitally missing teeth are genetic problems - just like humans, sometimes these things just happen during development. However, in many cases genetics do play a role, and so caution needs to be exerted when planning breeding that involves an affected dog or its close relatives. Dental xrays can be used to determine the presence of adult tooth buds prior to eruption, from 8-12 weeks of age. Deciduous tooth Xray revealing a congenitally missing permanent second premolar tooth in a six month old pup. The deciduous tooth is still in position, with no sign of the permanent tooth underneath it. If the tooth is present but unerupted, early detection is critical. Commonly, something is obstructing its eruption, such as thickened gum tissue, a narrow bony socket opening, or another tooth blocking the pathway (commonly a persistent deciduous tooth, or a neighbouring adult tooth). In other cases the tooth may be deformed or in the wrong position, and therefore unable to erupt. 1 The exceptions here are all molar teeth, and the first premolar teeth, which do not have a deciduous predecessor in dogs

12 Persistent baby teeth An eight month old Pomeranian with persistent deciduous teeth sitting over a bony swelling in the upper jaw, which was suspected to be an unerupted permanent tooth. Xray of the same dog showing an unerupted permanent upper fourth premolar (carnassial) tooth (red arrow), which became impacted due to persistent deciduous upper third and fourth premolars (blue arrows). What can we do about unerupted teeth? If a tooth is missing, it should be investigated with dental xrays as soon as it is noted to determine if there is a tooth hidden below the gum. If the tooth is congenitally missing, no intervention is required. In fact, depending on which tooth is missing, this may be a good thing for the dog as far as health and function goes, if it reduces the very overcrowding that we are concerned about. If an unerupted tooth is detected early, before the eruption process has finished, it may be able complete its eruption once the cause of impaction is surgically corrected (eg removing the tooth, bone or gum tissue that is impeding eruption). Sadly, in other cases, normal eruption may not be possible, even with advanced surgery. This is especially true if the tooth is deformed, poorly positioned or orientated, or the eruption process has finished (closure of the root will mean further eruption is not possible). 11

13 Unerupted teeth should be surgically extracted as they can form a dentigerous cyst around themselves. These destructive cysts can grow to occupy most of the jaw, destroying the surrounding bone and leading to facial deformity, tooth loss, jaw weakness and even jaw fracture. This seven year old dog had a missing lower right canine tooth that had never erupted (above). Xrays confirmed that the tooth was indeed present, but had become impacted behind a lower incisor, and was therefore unable to erupt (below left). A huge dentigerous cyst had formed around the tooth, destroying the jaw bone. Despite the high risk of jaw fracture, it was successfully surgically extracted and the cyst tissue removed (below right). This post- surgical xray shows the incredible amount of destruction a dentigerous cyst can cause. Fortunately, while the remaining bone was only about half a millimetre thick, the jaw healed uneventfully. 12

14 UNDERERUPTED TEETH AND PERICORONITIS The crown of each tooth is covered in a hard mineralised material called enamel, while the root is covered in cementum, which is closer in composition to bone. The gum normally forms its seal around the tooth by attaching to the cementum just where it meets the enamel. Gum cannot attach to enamel. If a tooth only partially erupts, part of the crown remains submerged below gum level. This creates a deep pocket around the crown of the tooth where the gum cannot attach to it. This pocket traps food, debris, plaque bacteria and pus, leading to severe inflammation around the tooth, called pericoronitis (meaning inflammation around the crown ). Pericoronitis can be very painful - in fact, this is one of the most common reasons humans have their wisdom teeth removed! Undererupted premolar tooth this dog is only six months old and already has significant inflammation (pericoronitis) due to the pocket around this tooth If a partially erupted tooth gets stuck underneath the crown or roots of an adjacent tooth (due to overcrowding), a proper gum seal cannot form between the two teeth, resulting in a direct pathway for bacteria to enter the jawbone. The resulting periodontal disease can then result in premature loss of both the undererupted tooth and its neighbour. What can we do about undererupted teeth and pericoronitis? Early identification of undererupted teeth and extraction can save the dog from the pain and infection that they cause. It can also save any adjacent, more important teeth from irreversible damage. While many undererupted teeth go undetected (as the partially exposed crown is not necessarily flagged as abnormal but just small ), having your dog s dentition examined by someone who is very familiar with the normal shape and position of the teeth may allow early detection. Dental xrays can then be taken to assess what is happening below the gumline, so that a treatment plan can be made.

15 TRAUMATIC BITE DEVELOPMENT (MALOCCLUSION) In dog breeds that are of similar size and facial profile to their wild ancestors (mesocephalic or mesaticephalic head- type), the muzzle length provides plenty of room for all 42 teeth to sit in a scissor bite arrangement, with smooth arcades that are not crowded. While smaller dogs obviously have smaller jaws, this has not always been bred for in a proportional way. The brachycephalic facial profile has become popular, a relatively short muzzle, even when the overall smaller size of the dog is taken into account. Several smaller breeds, such as the Pug, Pekinese, French Bulldog, Lhasa Apso and Shih Tzu, are typically undershot (short upper jaw compared with lower jaw), which can lead to a traumatic bite if the upper incisors are striking the lower incisors or the soft tissues on the floor of the mouth. Even in small breeds where a scissor bite is the standard, such as the Pomeranian, Cavalier King Charles Spaniel, Chihuahua, and Yorkshire Terrier, there is less room for error when the jaws are smaller and tighter, so traumatic malocclusions are not uncommon. Traumatic malocclusion - the lower canine in this seven month old pup is hitting the upper gum and incisor because there isn t enough space for it to move into a comfortable position. It is also crowded against the lower incisor, with no space for a proper gingival seal between these teeth. In many cases an undershot jaw or other jaw- related malocclusion does not cause the dog any problems, and they can eat without trauma or pain (otherwise all brachycephalic dogs would be in trouble!). However, if there is any trauma occurring, it needs to be resolved for the dog s health and welfare. This includes both damage to the soft tissues (the gums, lips, tongue) and the teeth (when teeth strike or rub each other, painful pulp inflammation or excessive wear can occur). Painful ulcers behind the lower incisor teeth in a nine month old dog with a rostral crossbite (undershot jaw). These are caused by the upper incisors digging into the floor of the mouth every time she closes her mouth. 14

16 Always remember that dogs are very adept at hiding oral issues, and will not show trouble eating or signs of pain unless they are in extreme pain. Therefore it is important to have your dog s bite thoroughly assessed to ensure that the jaw arrangement is not causing discomfort that will permanently affect their quality of life. What can we do about malocclusions? If there is a traumatic malocclusion, the best type of intervention will depend on the exact nature of the trauma. Options may include orthodontic movement of teeth into a better, more comfortable position, surgical shortening of teeth to stop them from hitting other tissues or teeth (odontoplasty or vital pulpotomy and capping), or selective extraction of teeth. Taking it back a step, it is also important to take jaw length issues into consideration when breeding smaller dogs. While pups with sweet, short faces are undeniably cute and irresistible, and most live happy and comfortable lives, we don t want to make them even more prone to dental and oral disease by poor breeding choices. Selecting for a correct bite or more moderate facial profile may decrease the risk of future puppies being born with uncomfortable or poorly functioning mouths. 15

17 PERSISTENT DECIDUOUS (BABY) TEETH While not actually a result of overcrowding, persistent baby teeth can exacerbate the overcrowding seen in small dogs. In fact, smaller breeds are prone to problems with retained deciduous teeth, which is ironic as there is very little room in their mouths to start with! Like humans, dogs have two sets of teeth, with their deciduous teeth being replaced by the permanent (adult) ones during the first six months of life. The molar teeth and the first premolars do not actually have a deciduous predecessor; so all deciduous teeth should have been lost by six months of age. The following table gives an indication of when each type of deciduous tooth erupts, and when it is replaced by the adult version. Deciduous teeth (weeks) Permanent teeth (months) Incisors Canines Premolars Molars Sometimes deciduous teeth are not shed because there is no permanent tooth present to replace it. However, if a permanent tooth does erupt without loss of the deciduous tooth, both teeth will end up sharing the same socket. The general rule of thumb is that there should never be two teeth in the same socket. Persistent deciduous teeth are bad news for dogs for two main reasons: 1. Similar to crowded teeth, if there are two teeth in one socket, the surrounding gum cannot form a proper seal between these teeth, leaving a leaky pathway for oral bacteria to spread straight down the roots of the teeth into the jawbone. Trapping of plaque, food and debris between the teeth also promotes accelerated periodontal disease. This not only causes discomfort and puts the adult tooth at risk of early loss, it allows infection to enter the bloodstream and affect the rest of the body.

18 Retained deciduous upper canine tooth predisposes the adult tooth to periodontal disease, Trapped debris and plaque can already be seen in this six month old pup. 2. If the deciduous tooth is still firmly in position as the permanent tooth is erupting, it will force this tooth into an abnormal position. In small dogs with little space to spare in their mouths, this can cause a significant traumatic malocclusion. For example, the permanent lower canines normally erupt on the inside of the deciduous teeth. If they are forced to erupt alongside them, they can end up in an abnormally narrow position. This often results in these teeth striking the roof of the mouth, causing pain and damage many times a day, every day. Retained lower baby canines (green arrows) force the erupting adult canines (red arrows) into an abnormally narrow position. 17

19 Similarly, the permanent upper canines normally erupt in front of the deciduous ones, so pushing them further forward can result in trauma to the inside of the upper lip. The gap in front of the upper canine (where the lower canine normally slots into) is also closed down, forcing the lower canine inwards to strike the palate, or outwards to hit the lower lip. Retained upper baby canine (green arrow) forcing the adult canine (red arrow) to erupt in a more forward (mesial) position. This closes the gap where the lower canine usually sits, and may force it into a traumatic position. What can we do about persistent deciduous canines? When persistent deciduous teeth are associated with an erupting adult tooth, extraction should be performed as soon as the adult tooth is coming through, especially if the occlusion is tight and the risk of developing a significant malocclusion is high. It is crucial that the whole tooth is removed, including the root, otherwise it will still block the correct positioning of the permanent tooth, and can act as a source of infection. Dental xrays prior to extraction are highly recommended, to determine whether the root is fully intact, or whether some resorption has occurred. Post- extraction xrays will then confirm that no root fragments have been left behind. In cases where the deciduous tooth remains and no adult tooth appears, dental xrays should be performed to check for impacted or unerupted adult teeth. Treatment for these has been discussed earlier in this book. 18

20 SO HOW DO I MAKE SURE MY SMALL DOG HAS A BIG SMILE? We cannot rely on dogs to tell us when they have oral pain. It is up to us to be vigilant and watch for signs of developing problems. Train your pup to allow handling and examination of the mouth from an early age. Things can change quickly - check their teeth and bite formation frequently as they grow. Don t assume that older dogs have no problems just because they are not telling you about it. Here is a checklist of some of the things to look for: Check the number of teeth (any missing or extra teeth?) Check the position of the teeth (overcrowded, rotated, out of alignment, undererupted?) Check the jaw length and the way the teeth fit together (is there any abnormal contact between teeth and oral tissues?) Check for redness, swelling, discharge or discoloured deposits on the teeth Does the breath smell bad? Note any problems eating, chewing or playing Seek veterinary care as soon as a potential problem is noticed your local vet is the place to start. You can also call me on or me anytime on christine@sydneypetdentistry.com.au for advice or assistance. Remember, early recognition and treatment is crucial if we want to keep your dog happy and healthy. Many issues are detectable at an early age. The sooner we treat dental problems, the more chance your dog has of having a healthy, comfortable mouth for life.