Pet Dental Education

Below are common pet dental conditions, side effects, and treatments

Pet Tooth Resorption

While pet tooth resporption is typically thought of as a feline condition, we are seeing more and more of this in our canine patients as well. This problem is very common in cats, with studies suggesting that up to 60% of cats over 6 years of age are affected. Feline tooth resorption is second only to periodontal disease in the overall incidence of oral disease.

As of yet, we do not know exactly causes pet tooth resorption. What we do know is that they result from the activation of cells called odontoclasts. These cells are responsible for the normal remodeling of tooth structure. In this disease process, the odontoclasts inappropriately continue to resorb tooth structure until in some instances the entire tooth is lost.

Tooth resorption lesions start on the roots of the pet's teeth where the cells start destroying the underlying root structure. Over time, the resorption typically extends into the crown of the pet tooth (the part of the tooth that you can see above the gumline). The tooth’s outerenamel is undermined which will cause it to break off, exposing the underlying tooth structure which is called dentin. The dentin layer is very sensitive, and when the protective enamel layer is lost tooth pain results.  Tooth resorption therefore becomes very painful, especially when the lesions are advanced. If you probe one of the lesions even under general anesthesia, the cat will react. However, most cats will not show evidence of oral pain, even when the tooth is fractured with an exposed root canal.  In fact, the teeth can be so painful that even cats under general anesthesia often react with a pain response when these teeth are probed with dental instruments. 

Because tooth resorption starts below the gumline and progress into the crown of the tooth, they are first seen at the gumline. The teeth most commonly affected are the premolars, followed by the molars and finally the canine (fang) teeth. The majority of the lesions are on the outer (cheek) surface of the tooth, however they can also seen on the inside (tongue) side of the tooth as well.

Diagnosis is made by a combination of visual and tactile examination in addition to dental x-ray. Resorptive lesions are initially seen as little erosions along the gumline with associated gum inflammation. These lesions can progress to large holes in the teeth, eventually destroying most of the tooth. In severe cases, the entire crown of the tooth can be lost, with only the roots remaining under the gumline. These areas will usually be rough along the gumline when an explorer instrument is rubbed over the suspected lesion.

Veterinary dental x-rays are absolutely critical for treating patients with tooth resorption. First of all, x-rays are necessary to diagnose (find) lesions under the gumline. Secondly, x-rays are also required in order to determine the proper method of therapy and ultimately resolve the painful condition.(See below).

Currently, the only accepted method of treatment for tooth resorption is extraction.  In general, complete extraction of the tooth and all root structure is recommended. However, extraction of these teeth is often quite challenging. This is because it is very common for the roots to be significantly resorbed and replaced by bone, making extraction by a surgical approach necessary. On occasion, the roots can be completely replaced by bone.  This finding has led to the development of a technique called crown amputation, where the crown of the tooth (the part of the tooth above the gumline within the mouth) is removed, the area smoothed and sutured closed, allowing the body to continue resorbing the roots.  This is a much less invasive procedure than a surgical extraction.

However, crown amputation can only be performed with advanced resorptive lesions if no root structure remains. Veterinary dental x-rays are required to determine this. Always insist on dental x-rays when taking your pet to the veterinarian for a dental procedure. 

Restoring (filling) tooth resorptive lesions is no longer recommended. This is because there is no way to stop or slow down the resorptive process and it just continues to progress under the filling.  In a short period of time (usually around 6 months), the tooth loss will progress to the point where the filling falls out and extraction is necessary.  Appropriate initial treatment will save the pet from enduring continued tooth pain.

Retained Deciduous (Puppy) Teeth 

A deciduous pet tooth is considered retained as soon as the permanent (adult) tooth erupts. The permanent pet tooth does not need to be fully erupted for the deciduous to be considered retained.

Cause of retained diciduous (puppy) teeth

The most common cause for a deciduous tooth to be persistent is an incorrect eruption path of the permanent. This will result in the deciduous tooth staying in the mouth and the permanent tooth erupting alongside. This is contrary to the classic but mistaken belief that a retained deciduous tooth causes the permanent tooth to erupt in an unnatural position.


This is most common in toy and small breed dogs, but can occur in any breed as well as cats.  The most common teeth affected are the canines, followed by the incisors, and premolars; and it is typically bilateral. Oral exam will reveal additional teeth in the arcades, which often appear crowded. In addition, the adult teeth are typically deflected into an abnormal position.

This unnatural position may cause tooth or gum trauma leading to possible infections of teeth or even the nose.   Studies have shown these orthodontic problems can occur within 2 weeks after the adult teeth erupt.  In addition to orthodontic consequences, periodontal problems also occur with retained deciduous teeth. This is due to the adult and puppy tooth being crowded together. The abnormal anatomy results in a weakened periodontal attachment and increased susceptibility to future periodontal (gum) disease.  This is even more concerning given the fact that the patients who tend to retain teeth (toy and small breeds) are also more prone to periodontal disease.

Treatment for retained diciduous teeth

There should never be two teeth of the same type in the same place at the same time.

Therefore, any persistent deciduous teeth should be extracted as early as possible. Do not waituntil 6 months of age to perform the extractions along with neutering. The time of adult tooth eruption is 3-4 months for incisors and 5-6 months for canines. You should examine your pet’s mouth at least once a week to ensure the prompt removal of these teeth.

Dental radiographs are absolutely critical to the proper performance of deciduous extractions, because there is often some degree of resorption of the deciduous root. 

The extraction of deciduous pet teeth can be very difficult due to the considerable length and thin walls of the deciduous tooth. Resorption of the retained deciduous tooth can also compromise the extraction. Dental x-rays provide this information which allows the practitioner to remove the tooth less invasively. In some cases, the root may be completely resorbed, making the extraction simple. However, if the veterinarian does not perform x-rays to find that the root is already gone, they may attempt to surgically remove it, causing unnecessary pain and trauma to the pet. Some veterinary dentists perform surgical extractions for deciduous canines; however, at Veterinary Specialties and Oral Surgery we generally perform a less invasive closed technique.

A retained root tip left behind after an extraction attempt may become infected, or more commonly act as a foreign body and create significant inflammation.  There are rarely any clinical signs associated with this, but the patient suffers regardless. Dental radiographs should be exposed following all extractions to confirm complete removal of the deciduous tooth.

Abscessed Teeth

These are also commonly called "carnassial abscesses" because they most often occur with fractures of the maxillary fourth premolar. However, any infected tooth can result in a clinical abscess. It is critical to note that these teeth have been dead and infected for a long time (sometimes years) and have just recently showed outward clinical signs. The patient has been subclinically infected for a long time. They are most often associated with a complicated crown fracture. However, it is critical to note that uncomplicated crown fractures can often result in clinical abscessation. The infected teeth harbor anaerobic bacteria which create a constant low grade infection through the apex and into the surrounding bone. Oral infections may be spread by the bloodstream to the vital organs. Dental radiographs are required to definitively diagnose an abscessed tooth. Skull films are generally insufficient to diagnose this subtle pathology associated with most tooth root abscesses. The presence of a tooth fracture alone does not necessarily indicate that the tooth is the cause of the infection/swelling. The presence of periapical rarefaction is the diagnostic key. Furthermore, it is recommended that the entire arcade be radiographed to ensure that there are not additional teeth involved. Emergency treatment: Emergency treatment is directed at relieving the pain and decreasing the amount of infection. Pain medications should be prescribed in addition to broad spectrum antibiotics. This treatment should alleviate the acute issues, but it will not solve the problem. The tooth must be definitively treated, and treatment should be performed before the antibiotics are finished to avoid developing resistance. Definitive therapy: Once the tooth becomes infected, there is no way to effectively medicate the root canal system. Further therapy is therefore required, regardless of the resolution of the acute problem. The infection will smoulder for a period of time and then recur, leaving the patient to suffer through that entire intervening period. Definitive treatment options include complete extraction or ideally root canal therapy.

Broken, Fractured Pet Teeth

Broken (fractured) teeth are a very common occurrence in dogs and cats. Pet teeth can break due to trauma (hit by a car, ball, or rock) or due to chewing on hard objects. Any pet tooth can break, however some teeth are more commonly fractured than others, such as the canine (fang) teeth in the dog and the cat, and the upper fourth premolar (large tooth on the upper jaw in the back of the mouth) in dogs.

There are two categories of broken pet teeth: those that directly involve the root canal (termed complicated crown fractures) and those that do not extend deep enough to expose the root canal, but rather only expose the layer beneath the enamel which is called dentin (uncomplicated crown fractures).  Both of these types of tooth fracture require therapy, but the treatment can be very different.

Pet teeth with direct root canal exposure are excruciatingly painful to a dog or cat. Unfortunately, only very rarely will animals show discomfort, as they are evolutionarily conditioned to mask pain fairly well, preferring to suffer in silence. This allows owners (and veterinarians) to ignore the problem, as “it doesn’t seem to bother the pet”. But we now know that these animals are suffering with consequences both locally in the mouth as well as systemically throughout the body. This means that in today’s current age of veterinary medicine, it is no longer appropriate or acceptable to ignore broken teeth in our patients. We have had numerous clients who have told us that their pet is not bothered by its broken tooth when it is discovered, that later tell us joyfully that their pet is acting “5 years younger” just two weeks after the problem is fixed.

The reason that a broken pet tooth with direct pulp exposure presents a problem is that after the tooth is fractured, bacteria from the mouth gain access to the root canal and infect the tooth. Eventually, the tooth will die and become a bacterial haven. The bacteria then leak out through the bottom of the tooth, and infect the bone in that area. Eventually, the bacteria cause bone destruction around the tips of the tooth root. Next, the blood vessels in the area pick up the bacteria and spread it to other areas of the body, including the liver & kidneys which filter the blood, and potentially to the heart valves, which damage these vital organs.  In fact, infected teeth (and periodontal disease) can so greatly affect the rest of the body and its vital organs that we have had numerous patients with elevated liver and kidney enzymes found on the pre-op blood which then improve or return to normal levels within two weeks of the dental procedure.

Occasionally, the infection at the root tips will get so bad that an abscess will break out through the skin and appear as a wound on the face, often below the eye. This most commonly occurs with a fracture of the upper fourth premolar in dogs, and it is known as a carnasial tooth root abscess. It can also happen secondary to an infected canine as well as most other teeth. In cats, an abscess will usually be due to a fractured canine tooth, but due to the shortness/shape of the nose, this wound will open below the eye as well. Antibiotics will usually resolve the problem for a while, but invariably the problem will continue to reoccur if the offending tooth is not appropriately dealt with.

Treatment Options for Broken Pet Teeth

There are three options for treatment of a fractured tooth with direct pulp expsure, and ignoring it is NOT one of them. This problem can only be solved with either root canal therapy, vital pulp therapy, or extraction.

The first and best option to treat fractured tooth that is otherwise healthy is root canal therapy.
This procedure removes the infected root canal tissue (called the pulp), medicants to help prevent future bacterial contamination. This is most commonly done for canines in dogs and cats, and the upper fourth premolars and lower first molars in dogs. However, any tooth can be saved in this manner. The advantages of root canal therapy over extraction of the tooth include:

    Saving the tooth
    Preserving the strength in the jaw
    Avoiding surgical pain
    Especially for large teeth
    Decreases risk of surgical complications

Vital pulp therapy (VPT) is only recommended in pets under 18 months of age. This is because the teeth are generally not mature enough for root canal therapy until that age.  Once the teeth are mature, root canal therapy has a much better prognosis. However, if VPT is to be performed, it should be done as soon as possible

The final option is extraction of the offending tooth. Choosing this treatment option may depend on the tooth involved, degree of fracture, and any other disease issues. Extraction is the least   ideal option for the most “strategic” (i.e. useful) teeth which include the canine (fang) tooth, as well as the upper fourth premolar and lower first molar teeth in dogs this is the last option. There are several reasons we prefer to extracting these teeth if possible.

These are very large teeth with very large roots in animal patients. The root of the canine tooth is twice as long and wider than the crown (the part you can see). Extraction of these teeth requires more invasive oral surgery, i.e. they are not simple extractions.   The patient loses the function of the tooth, which can be very important for chewing in some cases.

Orthodontic problems can occur as a result of losing of the tooth.

We try to avoid extraction in cases of otherwise healthy teeth.

Uncomplicated crown fractures are approached with different treatment options. These are also a very common finding on oral exam, particularly in large breed dogs. The most common teeth involved are the carnassials (maxillary fourth premolar and mandibular first molar) as they are the primary chewing teeth.  However, any and all teeth can be fractured. These fractures almost always result in exposure of the underlying tooth structure called dentin. This will uncover dentinal tubules which contain what amounts to nerves and creates significant pain for the patient.  

This is similar to us having a sensitive tooth from a deep cavity. In addition, some of these teeth will die either due to the trauma, inflammation, or direct pulpal invasion via the dentinal tubules.  For these reasons, it is recommended that these teeth be radiographed to ensure vitality. If the teeth are dead (evidenced by bone loss at the tips of the teeth) the teeth need to be root canalled or extracted.  If the teeth appear to still be alive, the application of a bonded sealant is recommended to decrease sensitivity, block off the pathway for infection, and smooth the tooth to decrease periodontal disease.

Discolored Pet Teeth

Any pet tooth that is not the normal color is almost certainly dead and infected. This means that teeth which are purple, yellow, grey, or brown are very likely to be a significant problem for your pet. In fact, it is estimated that 93% of discolored teeth are dead and infected, which means that can be painful and/or infected to your dog or cat. Unfortunately dogs and cats almost never show obvious signs of oral pain, therefore they often go untreated. 

It is important to determine if the discoloration is coming from within the tooth or on the surface. Surface staining can be caused by metal or from enamel wear and is usually not a major problem. However, if the whole tooth is discolored, then it is typically not a surface problem but rather an internal tooth issue and is in all likelihood the tooth is dead.

The main cause of tooth death in an intact dog or cat tooth is the disruption of the tooth’s blood supply. The disruption usually occurs due to trauma, either to the jaw or to the tooth itself. The only symptom/sign you may see is a discoloration of the tooth. Once the tooth dies, it can become infected through what used to be the blood supply. Once the tooth becomes infected, it acts as a bacterial fortress allowing the infection to spread out to the rest or the body.

We previously thought that we could to rely on dental x-rays to determine if a discolored tooth is infected. However, a study in 2001 showed that almost all discolored teeth are dead and/or infected regardless of their appearance on x-ray. In addition, it has been our clinical experience that all discolored teeth are dead.

Therefore, we recommend treatment for all discolored pet teeth. Ideally, this is root canal therapy. A root canal procedure will save the pet's tooth and is actually much less painful that the alternative option, extraction. Consequently, extraction is a good treatment option for small teeth, however for larger teeth (like canine (fang) teeth) root canal therapy should be the first choice.

Pet Periodontal Disease

"Missing” Pet Teeth 

If you notice your pet is missing a tooth, it can be a serious problem. It is exceedingly common for teeth to be absent in our pets. In some cases, the tooth is truly missing, while in others the tooth/root is actually present under the gumline. These teeth are usually a problem. Do not assume a tooth is truly absent or that it was previously extracted just because it is not seen above the gumline. Dental x-rays must be taken of the area to confirm true absence of the tooth. It is critical to note that if the tooth is truly absent, no therapy is necessary, however teeth under the gum can cause serious problems. Therefore, all “missing” pet teeth should be x-rayed to determine true absence vs subgingival problems.

Possible reasons for “missing” pet teeth include:

    1. The pet was born without the tooth. This is generally considered to be a genetic problem, but can also occur secondary to significant in utero or neonatal issues. This is common in small, toy, and brachiocephalic breeds, No specific therapy is necessary.
    2. Previously exfoliated or extracted. This is rare in young patients, but quite common in mature and geriatric animals.   Exfoliation (i.e. the tooth has fallen out on its own) most commonly results from periodontal disease, but may also be caused by trauma.  In older animals, extraction is a     more likely cause. In these cases, dental x-rays will usually reveal evidence of bone healing.  Again, no specific therapy is necessary.
    3. Fractured below the gum. This condition is also rare in young patients, but common in adults.  Roots under the gum often occur as a result of an incomplete extraction attempt.  Dental x-rays can confirm a retained root and find infection if present.  Surgical extraction is generally recommended to alleviate pain and infection.
    4. Impacted or embedded teeth. These teeth may be malformed or normal, but do not erupt into the dentition because they are blocked by a structure such as bone, tooth, or most commonly by an area of thick and firm gingiva called an operculum. This condition is most common in the first and second premolars of brachiocephalic breeds. In general, we recommend that these teeth be extracted to avoid a dentigerous cyst.

Unerupted teeth may create a dentigerous cyst. It is estimated that approximately 50% of unerupted teeth will lead to a cyst under the dog or cat's gums. These cysts can grow quite large and be disfiguring, and can ultimately result in a jaw fracture. Furthermore, these cysts can become infected, creating significant swelling and pain. Finally, these cysts can transform into a cancer. Treatment recommendation is surgical removal of the cyst and all involved teeth. The cyst lining should be sampled and submitted for biopsy.  The addition of a bone regenerative substance is beneficial in the treatment of large lesions. Contact our veterinarians at Pet Medical Center of Westerville to find out how your pet can benefit from a dental cleaning.

Dentigerous Cysts

Feline Stomatitis


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