The tooth, the whole tooth and nothing but the tooth….about teeth
February 6, 2014
From the desk of Dr. Voorheis
“Whadaya mean I have to brush my pet’s teeth?” “Are you serious?” “How do I do that?” “Why do I have to do that?” These are questions I hear all the time from clients. These questions are great because it gives me the opportunity to provide answers and educate people about the importance of oral hygiene in our pets. And believe me….it is VERY important. Things that happen in a pet’s mouth can not only cause poor dental hygiene, but they can also cause residual health issues in the body’s major organs. So let’s talk about teeth!
February is National Veterinary Dental care month. This is a month devoted to highlighting your pet’s dental care. My disclaimer on this subject is while I think it’s a fantastic way to get clients and veterinarians to focus on dental care for their pets, it shouldn’t be a focus for only one month each year. Our pets need dental care year round, much like flea control. But that’s another week in the life of the blog. Let me put it to you this way – are you going to brush your teeth for only one month of the year? Are you going to have your kids brush their teeth for only one month of the year? So why should we focus on our pet’s dental health for only one month every year? Let’s make dental care an ongoing goal for our pets.
I’m going to give you some fun facts before getting into more depth on teeth and oral care. For starters, mammalian teeth are pretty cool and they are not all the same. The shape of the tooth pretty well allows us to classify the animal’s eating habits such as carnivore, omnivore, herbivore, etc. Teeth are either polyphyodont or diphyodont. Huh? Polyphyodont teeth are continuously replaced like in kangaroos, manatees, and elephants. Diphyodont teeth are teeth that have two sets, i.e, deciduous teeth (baby teeth) and a permanent set of teeth. Some baby teeth are lost before birth (or shortly after) like in rabbits. Dogs and cats lose their deciduous teeth between 4.5 and 5.5 months of age. And the human mammal? We keep our deciduous teeth through childhood and when they fall out, the tooth fairy sticks a quarter under your pillow. Well, that’s what happened in my house back in the day. In veterinary medicine there is a general rule of thumb which is that no two teeth of the same type should be in the mouth at the same time. What does that mean? There should not be a “baby” canine tooth sitting next to an “adult” canine tooth. Never, ever. This leads to dental disease in a more rapid fashion due to overcrowding of the teeth. Now, more fun facts-Dental Formulas.
A dental formula indicates the numbers of teeth in the mouth. Here is more than you ever wanted to know about teeth: The “I” corresponds to Incisors, the “C” corresponds to Canine teeth, the “P” corresponds to Premolars and the “M” to Molars. The number in the numerator corresponds to upper jaw (maxilla) and the denominator represents the lower jaw (mandible). The number 2 indicates that this formula occurs twice, once on the left side of the mouth and once on the right side of the mouth.
Dog: 2 (I: 3/3, C: 1/1, P: 4/4, M: ⅔ ) total number of teeth = 42
Cat: 2 (I: 3/3, C: 1/1, P:3/2, M 1/1) total number of teeth = 30
Ferret: 2 (I 3/3, C: 1/1, P: 3/3, M ½) total number of teeth = 34
Rabbit 2 (I: 2/1, C: 0/0, P: 3/2, M 2-3/3) total number of teeth = 26-28
Opossum 2 (I 5/4, C: 1/1, P: 3/3, M 4/4) total number of teeth = 50
I, for one, am glad to not be cleaning Opossum teeth, they have very full mouths!
So where do we start in trying to determine whether or not our pet needs dental care? A ha! Trick question! They all do. I’ve included pictures in this blog (fancy!) and each picture represents a mouth that needs dental care. The “at home” examination begins with you, specifically with your eyes and your nose. If your dog or cat has bad breath, further investigation is needed. To put it bluntly, breath should not stink. If it does, you need to look at your pet’s mouth. I promise it’s not hard. Simply lift up the lip, one side at a time, and take a look. I’ve included some pictures in this blog to help you identify where your own dog or cat may fit in the grading scheme. Cats have the same stages of dental and oral cavity disease as dogs, plus a couple that are unique to cats (of course). Cat’s teeth are more prone to resorptive lesions which are erosions of enamel and painful. Cats are also prone to lymphocytic-plasmacytic stomatitis which is extremely painful. Keep in mind that a painful mouth, just like in humans, can lead to your dog or cat not eating.
While we’re on the subject of bad breath, allow me to elaborate. Halitosis (bad breath) is not always caused by dental or oral cavity disease. It can be caused by any one of these diseases:
- metabolic disease (diabetes mellitus, kidney disease)
- respiratory disease (inflamed nasal passages)
- gastrointestinal disease (megaesophagus – enlarged esophagus traps food – trapped food smells, stomach or intestinal foreign bodies, cancer)
- dermatologic disease (skin fold infections in the lip folds), trauma (electric cord injury, caustic agents, open fractures)
- infectious diseases (bacterial, fungal or viral) of the oral cavity, and masses within the mouth caused by cancer or autoimmune disease.
Bad breath can also be caused by our pets eating malodorous or offensive smelling items. Here is a disgusting dose of reality – some of you (and you know who you are) have “poo eaters” in your house. Yes, dogs who prefer to snack on their own poop. And let’s not forget the dogs who venture into the cat’s litter box. Cat poop is a magnificent delicacy for a dog. Gross but true. For so many reasons, best to keep them out of the litter box and out of their own poop piles.
But let’s get back to oral hygiene. Often, multiple components of halitosis are acting at the same time. A dog or cat may have periodontal disease and one of the situations mentioned above. It will take a trip to the veterinarian to sort this out and prioritize treatment. Since the subject of this particular blog is on dental care, let’s focus on periodontal disease. Perio what?
Periodontal Disease – How does it happen?
Periodontal disease is the most common dental disease and the major reason for loss of healthy teeth and oral pain. Periodontal disease affects the supporting structures of the tooth, which are the gingiva, alveolar bone (tooth socket bone), periodontal ligament (connective tissue attaching tooth to bone) and cementum which covers tooth roots. These structures make up the “periodontium”. Now, bear with me here: Plaque is the major cause of periodontal disease. Plaque is a soft, cream/light grey amorphous deposit. It consists of bacteria, salivary glycoproteins, extracellular polysaccharides mixed with cells, inorganic substances and water. It adheres to teeth and must be mechanically removed. It begins to calcify about 3 days after it is deposited. Calcified plaque is dental calculus (tartar). With me so far?
As plaque calcifies, and calculus thickens, it begins to extend beneath the gingiva. Harmful bacteria get involved and cause gingival inflammation and pain. The gingival margin and epithelial attachment begins to recede. The epithelial attachment begins to recede beyond the cementoenamel junction and a periodontal pocket forms (now we are beginning to abscess the tooth root). Eventually, alveolar bone and periodontal ligament is destroyed and when 50% of the periodontium is lost, teeth become mobile. The mobility results in pain, and continued infection results in tooth loss. In addition, periodontal disease can result in systemic bacteremia which may have a deleterious effect on organs such as the liver, kidneys and even the heart.
Time for a dental check up!
As veterinarians, we stage teeth and periodontal disease during a dental examination. You can ask your veterinarian what stage (or grade) he or she is giving the teeth. When we, as veterinarians, examine the oral cavity of a cat or dog, we will look for things like obvious masses or foreign bodies in the mouth. We will also look for evidence of gingivitis (gum inflammation), gingival hyperplasia (gum thickening), bleeding gingiva, small fractures of the teeth, dental calculus, receding gingiva, exposed roots and loose teeth. We will look for retained deciduous teeth (baby teeth). Based on what we find, we will rate or grade the condition of the oral cavity with one of the following categories:
Normal – Gingival tissue is coral pink or pigmented. It is firm and resilient. There is a sharp knife like border.
This is a normal mouth – note the pope smiling in the background – he agrees with me.
Stage 1 – Gingivitis – Gingival edema, erythema (redness), and loss of stippling occur (stippling can be best explained as a healthy orange peel texture to the normal gum), bleeding is found with minimal manipulation (probing with a dental instrument), there is no attachment loss. This stage of periodontal disease is completely reversible with performance of a complete dental cleaning and daily maintenance of oral health.
Stage 2 – Early periodontitis – Same as stage one, but minor attachment loss is present. Treatment is the same as stage 1.
This is a late stage 1 early stage 2 mouth. There is some calculi present on the upper canine tooth, and the lateral surface of the fourth premolar tooth. Increased pink color over PM4 indicates some gingival inflammation. This mouth can be managed with a professional cleaning, and followed up with home care.
The above mouth is a grade 2 mouth moving to grade 3. Even though there is not a lot of calculi present, this dog has more advanced gingival hyperplasia and is a heavy plaque former. Teeth cleaning followed by home care will make a significant impact in the health of this mouth.
Stage 3 – Moderate Periodontal disease – Moderate loss of attachment with the development of moderate to deep pockets (space between tooth and gum when probed). Gingival hyperplasia (thickening) and or recession may be present. Gingival recession will limit pocket depth. Bone loss of 30-50% may be found and only slight tooth mobility is present. Treatment is prophylaxis (cleaning), root planning (cleaning under the gum line) and possible gingival surgery). This stage is manageable but not curable. Following a cleaning, home dental care is a must.
Stage 4 – Severe Periodontal Disease – Severe pocket depth, major gingival recession is present. There is greater than 50% bone loss. Teeth are very mobile. Treatment will involve removal of severely affected teeth, with gingival surgery, possible sliding-flap surgery (which involves sliding gum tissue along to cover fistulas (holes) that communicate into nasal passages. This stage is manageable but not curable. Following a cleaning, home dental care is a must.
This is a grade 4 severe periodontal disease mouth. There is severe pocket depth and major gingival recession. There is greater than 50% bone loss, and there are several mobile teeth. Root planning and gingival surgery will be performed on less involved teeth. Severely mobile teeth with greater than 50% bone loss usually require extraction.
After your cleaning – it’s time for “at home” care
After this photo exhibit, I think I can safely assume that we might be willing to do a little bit of work to ensure oral cavity health for our pets. There are 5 different categories of home dental care to consider. The more of these you can manage, the better off your pet will be. The 5 options are tooth brushing, breath enhancers, diet, hard treats, and gingival exercises.
I must make a confession here. For years, I didn’t recommend it. I thought it impossible or ridiculous. In the pictures above, the late 1 early stage 2 mouth, and the normal mouth are my own dogs. In this blog I will repost pictures of them in six months, as I am committing here to brushing their teeth. I’ve been doing it for a while and they both tolerate it. “So wait a minute Doc, why do their mouths look so good, if you haven’t been brushing their teeth their whole lives?” The answer is below but first let’s talk more about brushing those teeth.
The trick to introducing tooth brushing to dogs is to go slow. Tooth brushing care should begin about one week after a dental cleaning. Remember, the gums may be painful due to the cleaning and/or extractions. Start by rubbing teeth with a piece of gauze dipped in bouillon and wrapped around the index finger. Start with the front teeth and as the dog becomes accustomed to having the teeth rubbed, proceed to rubbing the outside surface of the teeth between tooth and cheek tissue. When the dog is comfortable with this procedure, move to a soft child’s toothbrush or a veterinary designed toothbrush. There are also veterinary designed toothpastes – don’t use human toothpaste – they foam too much, dogs don’t like it and it can upset their stomach if swallowed.
Brushing a cat’s teeth is a different challenge. Good luck to you! Many will not tolerate it. You can start by gently rubbing on the outside of the mouth, from nose to the direction of the back of the mouth. You can then move to raising the lip and massaging gums with a finger, with the following step moving to gum massage with a piece of gauze wrapped around a finger. Some cats will then allow introduction of a toothbrush – definitely not all cats will allow this. Cat dental care is more challenging and many times will simply just have to rely on tooth cleaning diets rather than brushing.
These are over the counter chewable tablets designed to “improve the breath” and therefore the sociability of our pets. Make no mistake – this is a band aid for bad breath, not a cure for the reason behind the bad breath.
There are specific prescription diets designed to clean teeth while the dogs or cats eat. The best option is T/D by Hill’s Science Diet or a maintenance diet called oral care is the next best choice. These diets are designed to clean the teeth while a dog or cat eat. They are manufactured in such a way that the fibers in the kibble all run in one direction, thus scrubbing the tooth as the kibble is crushed from crown to gingiva. These have been around long enough for me to form an opinion of them. They work. Simply put, T/D works better than oral care, but both work to improve the condition of the teeth. They are maintenance diets that can be lifelong diets for dogs and cats. For over 13 years, oral care diets are the only foods I have fed my dogs. Pure and simple, I have been impressed with their effectiveness.
Hard treats are good, but mostly only clean the crown of the tooth. Carnivores (cats and dogs) generally gulp their food or give one quick crunch and then gulp it down. Even though the benefit is brief, treats do help by providing abrasion to the supragingival (above the gums) tooth surface.
The goal here is to recreate the natural carnivore oral behavior as it hunts prey, kills it, tears the skin and meat from the carcass and devours it bones and all. However, bone chewing can cause significant gastrointestinal problems in domestic pets. Chewing on bones or other hard objects that are harder than the teeth can also damage and break dog and cat teeth. A pink, purple, gray, or tan tooth is a dying or dead tooth and is a condition caused by chewing on objects harder than the teeth. Bone chewing also causes slab fractures on the cheek side of the largest premolar tooth, and tongue side fractures on the lower canine teeth. Rawhide chew toys, biscuits, synthetic bones, knotted ropes, and other such products provide exercise for the gums and abrasive action to help provide gingival exercises and to remove plaque from the crowns of teeth. It is safest for dogs to chew on items softer than their teeth.
I’ve enjoyed writing about periodontal disease in dogs and cats and I’ve only scratched the surface of what we could talk about with the oral cavity of dogs and cats. I will commit to another blog about other oral cavity diseases and specifically will write something about plasma cell stomatitis in cats. Fascinating stuff!
Your pet’s oral care will certainly take a commitment from you. There is work to be done after the dental cleaning so keep in mind it’s not a one stop shop when it comes to a healthy dog/cat mouth. Fortunately, there is significant reward for the commitment you make – a healthier pet with a healthier oral cavity. I can’t see a downside, can you?
Until next week………