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Diseases of the feline oral cavity (Proceedings)

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Apr 01, 2009

This lecture will be focusing on inflammatory diseases of the feline oral cavity. For the most part, these diseases can be diagnosed and treated in the general practice. The diseases we will discuss are periodontal disease, odontoclastic resorptive lesions, and gingivostomatitis.

When working up inflammatory diseases in the cat, it is important to know that at various stages of the disease process, they can display pathogenic behavior that is similar when compared to one another. Hence, diagnosing these diseases requires a wide variety of diagnostic tests and a thorough patient history. Finally, with all of these diseases, submitting tissue samples for histopathological analysis is a vital tool towards piecing together the diagnostic puzzle.

Treatment of these diseases requires a multimodal approach. This approach involves home care, medical therapy and surgical intervention. Oral hygiene provided by a good home care regimen can prevent or slow the progression of the inflammation. Medical therapy uses antibiotics, antimicrobials, antiseptics, antiinflammatories and antivirals. Surgical intervention usually means extraction in these cases.

Periodontal Disease

The first disease we will explore is periodontal disease. The pathogenesis of periodontal disease is pretty much the same when compared with the dog. In the cat, there are a couple of interesting manifestations of this disease.

Periodontal disease affects 85-95% of cats over 2 years of age Persians, Maine Coons, Burmese and Siamese tend to be more prone to early onset or severe periodontal disease. Geriatric, immunocompromised, or patients suffering from chronic systemic disease have a more difficult time fighting the disease.

Pathogenesis of Periodontal Disease

Pellicle - the oral cavity is a constantly moist environment. The pellicle is a thin film consisting of salivary proteins and glycoproteins. The pellicle protects and lubricates. Pellicle deposition occurs immediately after a dental cleaning. As the pellicle ages, it gives the oral bacteria a surface to adhere.

Dental Plaque - as bacteria colonize on the pellicle, it forms a biofilm on the inert surfaces of the tooth, namely the crown and becomes mature plaque. It forms within 24 hours of a dental cleaning. It is difficult to see but can be visualized using a plaque disclosing solution. The biofilm thickens as the aerobic bacteria consume oxygen and multiply, making the environment more suitable for anaerobic bacteria. An important thing to remember here is that dental plaque is not a disease, but is the cause of periodontal disease. Plaque that is allowed to accumulate will result in gingivitis.

Dental calculus - dog and cat mouths, unlike humans are slightly alkaline, an environment in which calcium salts are more likely to be deposited. Calcium carbonate and calcium phosphate salts are found in the salivary fluid. These calcium products crystallize on the surface of the teeth and mineralize the soft plaque. Calculus contributes to periodontal disease by keeping the plaque in close contact with periodontal tissues. The formation of dental calculus takes 2-14 days. The deep crevices along the surface of the calculus promote further growth of anaerobic bacteria because oxygen is low to unavailable. Calculus cannot be removed except by mechanical action (hand or power scaling).

Gingivitis - plaque extends subgingivally and the mixture of bacteria and cell degradation products become destructive on the periodontal soft tissues and inflammation occurs and gingivitis develops. Sulcus depths are usually normal. There are two forms of gingivitis - acute gingivitis and chronicgingivitis. Acute gingivitis is presents with red, swollen gums that easily bleed. Chronic gingivitis has calculus and plaque present with halitosis being the main complaint. Gingivitis is considered reversible, meaning that once the bacterial laden dental plaque is removed, the inflammation disappears. Not all sites with gingivitis proceed to periodontitis. Gingivitis can become more severe in patients with local or systemic conditions.

Periodontitis - inflammatory destruction of the coronal part of the periodontal ligament allows the apical migration of the bacteria. This causes the destruction of the periodontal attachment tissue (periodontal ligament, alveolar bone). In order to make a diagnosis of periodontitis, bone loss must be present. Periodontitis can have active and quiescent periods, which explains why you could see some teeth with root exposure or increased periodontal pocket depth, but no inflammation

Pathogenic bacteria cause the body to activate immune and non-immune reactions that are responsible for the tissue damage. It is the host response to plaque bacteria and not the virulence of the bacteria that causes the tissue damage. So, all cats will develop plaque, but not all will that plaque develop into periodontitis.

Purebred Cats and Periodontal Disease

In certain purebred cats there are unique forms of periodontal diseases.

Juvenile hyperplastic gingivitis - this commonly affects Abyssinian and Persian kittens. The patient will present with proliferative tissue that covers the teeth. This condition appears at 6-8 months of age. The lesions cause the patient to have difficulty chewing and brushing the teeth is hindered. The treatment is to perform a gingivectomy on the proliferative tissue with submission of a tissue sample for histopath.

Juvenile early onset gingivitis - this condition is seen in the deciduous and permanent dentition of young Persians. The sign is an erythematous line along the gingival margin that extends from the incisors to the molars. The treatment for this condition is regular professional cleanings and rigorous home care

Juvenile early onset gingivitis-periodontitis - this is commonly seen in Maine Coons, Siamese, and DSH kittens. The teeth will have heavy deposits of plaque and calculus with red and swollen gingiva. You will see on oral examination attachment loss, periodontal pockets, gingival recession and bone loss. The gum tissue bleeds so difficulty chewing will be expected. As in the previous disease professional cleanings and rigorous home care are advised in order to slow the progression of this disease. Some cases will not respond to treatment and extractions with oral biopsies will need to be performed.