Coming in August: Dr. Carmichael will complete his discussion on feline oral diseases including odontoclastic resorptive lesions, treatment options for fractured teeth, feline gingivitis/stomatitis syndrome and feline oral neoplasia.
Dental disease is common in domestic felines. In fact, dental problems are the most common disease that we see in cats, and many dental problems are painful.
The sensory nerves (branches of trigeminal nerve) that cause humans to experience dental pain are present in the cat as well. The most common sign of pain in cats, however, is no sign at all. By diagnosing and rendering appropriate treatment, we can eliminate pain and afford our feline patients a better quality of life.
Dental disease is not a diagnosis. There is no specific treatment for "dental disease." Specific treatment can only be recommended and performed when a specific diagnosis is discovered.
By making a diagnosis, we can offer specific and rational treatment or treatment options for the specific dental problem(s) encountered.
The vast majority of feline dental problems can be grouped into one of five disease categories: periodontal disease, feline odontoclastic resorptive lesions (FORL), fractured teeth, feline gingivitis/stomatitis syndrome and oral neoplasia.
When performing your oral examination, a diagnosis of one of the above-listed problems will direct you to a specific treatment recommendation.
Of course, there could very well exist multiple dental problems in the same mouth. Think of the cat's mouth as 30 individual little patients, each with the potential of having some problem. Recommend treatment on a tooth-by-tooth basis based on the results of your examination.
Kittens are born adentuous (without teeth). By 1 to 2 weeks of age, the deciduous or temporary teeth begin to erupt. The 6-week-old kitten should have a full complement of 26 deciduous teeth.
Between 4 and 5 months-of-age, the deciduous teeth will be shed, and the permanent teeth will erupt. By 6 months of age, a total of 30 permanent teeth will have erupted that comprise the complete feline adult dentition.
Photo 1 Depicts early-stage periodontal disease: gingivitis. Note the plaque and calculus accumulation, especially on the maxillary fourth premolar, where the gingivitis is most pronounced.This mouth could be brought back to a state of health with a dental prophylaxis and institution of a home care program.
These 30 teeth include 12 incisors, four canines, 10 premolars and four molars. If the primary dentition fails to be shed by the time the permanent tooth erupts, a condition called "retained deciduous teeth" occurs. The rule of thumb is to recommend immediate extraction of the retained deciduous tooth.
The dental formulas of the cat are:
Cat: Deciduous teeth: 2X (3/3 i, 1/1 c, 3/2 pm) = 26.
Permanent teeth: 2X (3/3 I, 1/1 C, 3/2 PM, 1/1 M) = 30.
Feline teeth are "hollow" and the hollow chamber inside the tooth-the pulp cavity (root canal)-contains the blood vessels, nerves and lymphatics that comprise the dental pulp. The pulp tissues communicate with the rest of the body through multiple small foramina located at the root apex (apical delta.)
The pulp chamber is surrounded with a tissue called dentin. Dentin is a hard tissue that is produced by odontoblasts, and forms the bulk of the tooth's structure. As the tooth ages, the odontoblasts continue to produce dentin, causing the dentin to thicken and the pulp chamber to narrow.
On the crown of the tooth, which is the part of the tooth visible above the gum line, a protective layer of enamel covers the dentin. The root dentin is covered by cementum, which is where the periodontal ligament fibers insert.
The periodontium consists of the structures "around the tooth" that function to attach the tooth in the mouth. The periodontium consists of the gingiva, the alveolar bone, the cementum and the periodontal ligament.
Pathologic conditions are more common in the mouth of the cat than anywhere else in the body.
Photo 2 shows moderate-stage periodontal disease: early periodontitis. Note the gingival recession and furcation exposures of the mandibular premolars and molar tooth. An intraoral radiograph of these teeth (not shown) documented 25 percent horizontal bone loss. The tissues that have been lost will not grow back. Frequent prophylaxis and at-home plaque control will be necessary to keep this from progressing.
A broad classification of feline dental pathology includes disease conditions that affect the teeth, and disease conditions that affect the structures around the teeth.
The common "tooth lesions" in cats are feline odontoclastic resorptive lesions and dental fractures.
The common "around the tooth lesions" include the lesions of periodontal disease (gingivitis, periodontitis), and the severe inflammatory condition called feline gingivitis/stomatitis syndrome (lymphocytic-plasmacytic stomatitis). The lesions of feline gingivitis/stomatitis syndrome include inflammation of the periodontal structures as well as the oral mucosa (and sometimes the lips and tongue).
Oral neoplasia can affect soft tissue, bone and tooth structure.
Histopathologic examination of oral mucosal lesions is required to confirm a diagnosis.
Most often the results-lymphocytes and plasmacytes-will be typical of an inflammatory response. However, the biopsy is necessary to rule out other inflammatory conditions such as eosinophilic granuloma and neoplasia.
Firm oral swellings, especially over the canine tooth roots, are sometimes benign bone proliferation secondary to feline odontoclastic resorptive lesions. Therefore, do not doom a cat to the poor prognosis of squamous cell carcinoma without the benefit of biopsy.
A minimum amount of equipment that is necessary for performing routine dental care in feline patients includes a high-speed dental drill and a dental X-ray machine.
Attempting to accurately diagnose and treat the most common dental problems in cats without intraoral radiography and high-speed drills puts both the practitioner and patient at a disadvantage.
The moderate expense of upgrading your dental operatory to include radiography and a high-speed drill will be rapidly recouped, and the benefits are immeasurable.
No small animal practice that performs dental procedures should be without this equipment.
Periodontal disease is very common in cats. Left untreated, periodontal disease can cause oral pain, oral abscess formation, osteomylitis, tooth loss and vital body organ infections from bacteremia.
Most cases of advanced periodontal disease in felines could have been prevented through a program of early disease detection and appropriate treatment.
Periodontal disease is caused by the presence of plaque bacteria on the teeth and the host's response to that bacteria. The combined effects of bacterial toxins and the products of the host's inflammatory response cause the periodontal tissues to become inflamed, and if not checked by professional intervention, destroyed.
An "over-response" by the host's immune system may explain why some individual patients or certain breeds (Maine Coon, Ragdoll, Oriental breeds and others) exhibit rapidly progressing and/or more severe disease.
The early stage of periodontal disease is characterized by halitosis and gingivitis. Because the cat's gingiva is very narrow, this gingivitis may not appear dramatic-but it is! (Photo 1, p. 12S.)
This early stage of periodontal disease, gingivitis, is one of the few oral disease conditions where we can perform treatment and return things to a good state of health. Especially in cats, we need to look for this at an early age. It is not uncommon to see cats at 6 or 8 months of age with significant oral inflammation, the so-called juvenile-onset gingivitis. If left untreated, by the age of 12 to 24 months, this may quickly progress to irreversible periodontitis.
Treatment recommendations for cats with early stage periodontal disease include frequent professional prophylaxis, and daily homecare.
Once periodontal disease has progressed into the more advanced stages, periodontitis, the treatment plan is geared more toward damage control than prevention (Photo 2, p. 12S). The loss of periodontal tissue (gingival, bone, periodontal ligament) that occurs with periodontitis is, in most cases, irreversible.
In cats, advanced periodontal disease can quickly progress to a point where extraction is the only valid treatment option remaining. If the goal is to save teeth, aggressive treatment combined with daily homecare is required. If advanced periodontal treatment (flap surgery) is being considered, make sure you have good radiographic documentation to rule out feline odontoclastic resorptive lesions (FORLs). The presence of FORLs will doom your periodontal treatment to failure.
Clinically, there are very few cases where advanced periodontal surgery is warranted in felines.
Photo 3 is an example of advanced-stage periodontal disease: established periodontitis. The gum recession on the maxillary premolar teeth corresponds with (not shown) radiograph evidence of substantial horizontal bone loss. These teeth will never be brought back to a state of health, and extraction is indicated. The canine tooth appears less severely affected by periodontal disease, but appears to have a crown fracture.
These select cases usually involve the canine teeth that have relatively longer roots. Because the roots of the incisors, premolars and molars rarely exceed 7-8 mm, periodontal pockets of similar depth that could reasonably be managed in a dog or in a human doom these short feline teeth for extraction (Photo 3, p. 12S). There is a fine line between prophylaxis and exodontia in the cat.
Daily tooth brushing is the best thing you can recommend for pet owners to do at home to promote good oral hygiene. Remember plaque bacteria can colonize on teeth in 24 to 36 hours. This means that within just a few days following your prophylaxis, the teeth are already starting to accumulate the plaque bacteria that cause periodontal disease.
There are several commercial diets that have been shown to significantly reduce plaque and tartar when fed compared to "regular" dry food diets. This isn't just marketing hype-studies document significant reduction in the plaque index for the foods tested.
Specifically these foods are Iams Daily Dental Care, Hills T/D (prescription diet) and Oral Care, and Friskies Dental Diet. With the incidence of periodontal disease so high, there are few reasons why anyone would not want to provide a diet that promotes good periodontal health.
Oral rinses, sprays and other such products also have a role in homecare.
These products are sometimes used after oral surgery when brushing is not appropriate. In pets that refuse brushing, these products may be the only kind of homecare possible.