The three most common oral problems in the cat are:

1.  Periodontal disease

2.  Chronic gingivostomatitis

3.  External root resorption

PERIODONTAL DISEASE

Periodontal disease is common in the cat. Very few animals do not require periodontal treatment by middle age; in fact, most require remedial therapy earlier in life.

The aetiopathogenesis of feline periodontal diseases is the same as in the dog, namely that the accumulation of dental plaque on the tooth surfaces incites inflammatory responses in the periodontium, resulting in gingivitis and periodontitis. Gingivitis is when the inflammation is limited to the gingiva; while periodontitis is when there is irreversible inflammatory destruction of the periodontal ligament and alveolar bone, resulting in loss of attachment of the tooth. Diagnosis of periodontal disease and differentiation between gingivitis and periodontitis requires oral examination under general anaesthesia. The clinical periodontal parameters that need to be evaluated for each tooth are gingivitis index (GI), periodontal probing depth (PPD), gingival recession (GR), furcation involvement and tooth mobility. Clinical (periodontal) attachment level CAL/PAL) can be measured or calculated. Teeth showing clinical evidence of periodontitis should be radiographed. It is essential to differentiate between gingivitis and periodontitis in order to draw up the optimal treatment plan for the individual cat.

The Gingivitis Patient

Gingivitis is by definition reversible. Removal or adequate reduction of plaque will restore inflamed gingivae to health. Once clinically healthy gingivae have been achieved, these can be maintained by daily removal or reduction of accumulated plaque. In other words, the treatment of gingivitis is to restore the inflamed tissues to clinical health and then to maintain clinically healthy gingivae thus preventing periodontitis.

Toothbrushing is known to be the single most effective means of removing plaque. Daily toothbrushing will restore inflamed gingivae to health and then maintain clinically healthy gingivae. While most dogs (puppies and adults) will allow toothbrushing, the adult cat is not generally as cooperative. However, kittens generally readily accept having their teeth brushed. Toothbrushing instruction can easily be incorporated into the consultations for primary vaccination and is highly recommended.

Mechanically reducing plaque accumulation by means of dietary texture (the use of a dental diet and/or dental hygiene chews) is an important part of preventive dental care in the cat. These products will reduce the accumulation of dental deposits and thus reduce the severity of plaque-induced gingival inflammation.

The Periodontitis Patient

Untreated gingivitis may progress to periodontitis. It is important to remember that periodontitis is a site-specific disease, i.e., it may affect one or more sites of one or several teeth. In most instances in a practice situation, periodontitis is irreversible. The aim of treatment is thus to prevent development of new lesions at other sites and to prevent further tissue destruction at sites which are already affected.

Home care is also a most important aspect of treating periodontitis. Following professional therapy, the owner must prevent or remove the accumulation of plaque on a daily basis. In our experience, adult cats with established periodontitis will not tolerate toothbrushing. Consequently, we extract teeth that have any evidence of loss of attachment.

The effect of dental diets or dental hygiene chews on periodontitis has not been investigated. It is unlikely that such products are effective in treating periodontitis. In fact, they may even be contra-indicated since we know that in an individual with severe periodontitis mastication results in a transient bacteraemia.

FELINE CHRONIC GINGIVOSTOMATITIS

Feline chronic gingivostomatitis (FCGS) is a poorly defined syndrome of unknown aetiology, characterised by focal or diffuse chronic inflammation of the gingiva and oral mucosa.

FCGS can present clinically as focal or diffuse inflammation. Patterns of clinical presentation have been identified as follows¹:

1. Gingivitis with Stomatitis

The gingival inflammation extends past the mucogingival junction onto the buccal and less often palatal/lingual mucosa. Lesions are usually symmetrical and the premolar and molar regions are likely to be more inflamed than the incisor and canine regions.

2. Stomatitis with Gingivitis

The inflammatory reaction is more intense in the rest of the oral mucous membranes than in the actual gingivae. In particular, the palatoglossal folds are inflamed, but there may be extensive ulceration or granulation of the gingival and/or buccal mucosa. The mucosa of the hard palate or the tongue is rarely affected. Affected cats are more likely to exhibit signs of oral discomfort than cats with predominantly gingivitis.

3. Faucitis

The term "faucitis" is a misnomer. By definition the "fauces" is the region medial to the palatoglossal folds. The inflammation, which is commonly called "faucitis", is largely confined to the palatoglossal folds and regions lateral to the folds. On close inspection, there is nearly always also evidence of gingivitis in the premolar and molar regions.

Note that these are patterns of distribution rather than distinct diagnoses. There is often overlap with a patient presenting with one or all of these patterns.

Cats with chronic stomatitis require a thorough work-up prior to any treatment. The purpose of the work-up is not to reach a diagnosis per se, but rather an attempt to identify possible underlying causes. Such a work-up includes testing for feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV); routine haematology and blood biochemistry and sometimes biopsy and microscopic examination of the affected tissues. Radiographic evaluation to identify the presence of other lesions (e.g., retained root remnants, external root resorption) is mandatory. Systemic diseases, e.g., chronic renal failure and diabetes mellitus, which may predispose to the development of severe gingival inflammation in the presence of plaque, must also be excluded before any treatment is initiated.

Historically, the intractable nature of the disease, in combination with a poor understanding of the aetiopathogenesis of FCGS has resulted in the widespread use of empirical symptomatic treatment regimens; however, their efficiency has rarely been documented. In a recent study various treatment regimens, including chlorhexidine rinses, antibiotics, corticosteroids and gold salts were investigated over a six-month period². In the short term, methylprednisolone was shown to be the most effective regimen. Over the long period, the individual clinical responses were found to be diverse and none of the treatment regimes demonstrated superiority.

Thirty cats with FCGS were treated by extraction of most or all of the premolar and molar teeth³. Twenty-four of the 30 cats (80%) were significantly improved or clinically cured at the time of follow-up, 11-24 months following treatment.

Based on the above studies, the current treatment recommendations for cats with FCGS include a combination of periodontal therapy and a home care regimen whereby plaque accumulation is kept to a minimum. In some cats, this may result in a reduction in inflammation. Unfortunately, many cats will not cooperate adequately with home care measures and plaque reforms beyond a critical level. These cats need extraction of premolar and molar teeth. In some cats, all teeth may require removal.

EXTERNAL ROOT RESORPTION

External root resorption may well represent the single most common dental disease seen in the cat. Resorptive lesions account for a large proportion of the clinical caseload in small animal veterinary practice.

Odontoclastic resorption refers to a disease process where the hard tissues of the tooth root surfaces are destroyed by the activity of multi-nucleated cells called odontoclasts. The destroyed root surface is replaced by cementum-or bone-like tissue. The process starts in cementum and progresses to involve the dentin where it spreads along the dentin tubules and eventually comes to involve the dentin of the crown as well as the root. The enamel is ultimately resorbed, or is so undermined that it fractures, and a cavity in the crown becomes clinically evident.

External root resorption can be classified into three basic types, namely surface, inflammatory and replacement⁴. While surface root resorption occurs in all feline teeth⁵, the lesions that are called odontoclastic resorptive lesions (ORL) are either inflammatory (associated with periodontal inflammation) or replacement resorption (unknown aetiology). The most common type of lesion seems to be replacement resorption of unknown aetiology⁶.

The lesions can be detected by means of a combination of:

 Visual inspection

 Tactile examination with a dental explorer

 Radiography

Visual inspection and tactile examination with a dental explorer will only identify end stage lesions, i.e., when the process is involving the crown and has resulted in an obvious cavity. Radiography will identify lesions that are localised to the root surfaces within the alveolar bone, which would not be detected by clinical methods. Consequently, radiography is required for diagnosis of ORL. In fact, a series of full mouth radiographs are recommended for all cats presented for dental therapy.

The aim of any treatment is to relieve pain, prevent progression of pathology and restore function. It remains a matter of debate as to whether replacement type ORL cause discomfort or pain to the affected individual. Based on the fact that pulpal inflammation occurs late in the disease process, it seems likely that lesions that are limited to the root surfaces and do not communicate with the oral environment are asymptomatic. However, once dentin destruction has progressed to such an extent that the process invades the pulp and/or a communication with the oral cavity has been established (when the enamel has been lost, thus revealing the dentin to the oral cavity), then discomfort and/or pain are likely.

To date, there is no known treatment, which prevents development and/or progression of replacement type ORL. It seems unlikely that such treatment can be developed without knowledge of the cause of the pathology. Currently, the suggested methods of managing odontoclastic resorptive lesions are:

 Conservative management

 Tooth extraction

 Coronal amputation

Restoration of the tooth surface has been recommended for the treatment of accessible lesions, which extend into the dentin and do not involve pulp tissue. Several studies have shown that tooth resorption continues and the restorations are lost ^7,8. Consequently, the use of restoration of odontoclastic lesions as a major treatment technique can no longer be recommended.

Conservative management consists of monitoring the lesions clinically and radiographically. This approach is recommended for lesions that are not evident on clinical examination, i.e., only seen radiographically and there is no evidence of discomfort or pain. As most lesions are only diagnosed when pathology is extensive, conservative management is rarely indicated in the general practice situation.

In most cases, extraction or coronal amputation of an affected tooth is indicated. With extraction, the whole tooth is removed. This is the gold standard. However, when the root has been extensively resorbed it is often not possible to extract all tooth substance and coronal amputation is indicated. As already mentioned, pre-operative radiographs are mandatory to allow selection of the appropriate treatment option.

References

1.  Harvey CE (1990):Feline oral pathology, diagnosis and management. In: Crossley DA & Penman S (eds) Manual of Small Animal Dentistry, British Small Animal Veterinary Association, Gloucestershire, UK, pp 129.

2.  Harley R, Gruffyd-Jones TJ and Day MJ (1999): Clinical and immunological findings in feline chronic gingivostomatitis, In: Proceedings of the 11th British Veterinary Dental Association's Annual Scientific meeting, Birmingham, UK.

3.  Hennet PR (1997): Chronic gingivo-stomatitis in cats: long term follow up of 30 cases treated by dental extractions. Journal of Veterinary Dentistry 14(1): 15.

4.  Andreasen JO (1988): Review of root resorption systems and models. Etiology of root resorption and the homeostatic mechanisms of the periodontal ligament. In: Davidovitch Z (ed) Proceedings of the International Conference on the Biological Mechanisms of Tooth Eruption and Root Resorption. Birmingham, UK: Ebesco Media, pp 9.

5.  Gorrel C and Larsson (2002): Feline Odontoclastic Resorptive Lesions: Unveiling the early lesion. Journal of Small Animal Practice 43, 482.

6.  Okuda A and Harvey CE (1992): Etiopathogenesis of feline dental resorptive lesions. Feline Dentistry. Veterinary Clinics of North America: Small Animal Practice. WB Saunders, Philadelphia, USA, pp 1385.

7.  Shigeyana Y, et al (1996): Expression of adhesion molecules during tooth resorption in feline teeth: a model system for aggressive osteoclastic activity. Journal of Dental Research 75, 1650.