Diagnosis of periodontal disease relies on clinical examination of the periodontium in the anesthetized animal. In addition, radiography is mandatory if there is evidence of periodontitis on clinical examination. It is essential to differentiate between gingivitis and periodontitis in order to institute appropriate treatment. In individuals with gingivitis, the aim is to restore the tissues to clinical health; in individuals with established periodontitis, the aim of therapy is to prevent progression of disease.
The following parameters need to be assessed and recorded for each tooth in all patients:
Gingival recession (GR)
Gingivitis is defined as a reversible plaque-induced inflammation limited to the gingiva (i.e., no loss of periodontal attachment).
Clinical Signs and Diagnostic Methods
Gingivitis manifests clinically as swelling, reddening and often bleeding of the gingival margin. It may be accompanied by halitosis. It is diagnosed clinically by means of a combination of visual inspection and tactile examination. The presence and degree of gingival inflammation is assessed based on a combination of redness and swelling, as well as presence or absence of bleeding on gentle probing of the gingival sulcus. Various indices can be used to give a numerical value to the degree of gingival inflammation present. In the clinical situation, a simple bleeding index may be the most useful. Using this method the gingival sulcus of each tooth is gently probed at several points and given a score of 0 if there is no bleeding and a score of 1 if the probing elicits bleeding. The patient with uncomplicated gingivitis will have normal periodontal probing depths (1–3 mm in the dog and 0.5–1.0 mm in the cat) and show no evidence of gingival recession, furcation involvement or tooth mobility. Radiography is not mandatory if the clinical examination reveals no evidence of periodontal destruction (i.e., periodontitis).
Gingival hyperplasia may be the result of plaque-induced inflammation (i.e., hyperplastic gingivitis). It may also be of idiopathic or familial origin, and it can be induced by certain drugs (e.g., hydantoin, cyclosporins). Gingival hyperplasia is common in some breeds (e.g., Boxer, Springer Spaniel). There is an increase in periodontal probing depths due to the gingival overgrowth.
Consequences to Affected Animal
Uncomplicated gingivitis is generally not associated with discomfort or pain in humans. In fact, it is an insidious process and the patient may be unaware of its existence. The significance of gingivitis is that, if untreated, periodontitis may develop as described earlier.
Gingival hyperplasia does pose an additional concern. The hyperplastic gingiva alters the position of the gingival margin and results in a false or 'pseudo' pocket. It is called a pseudopocket because the increased periodontal probing depth is not due to destruction of periodontal ligament and alveolar bone with apical migration of the junctional epithelium, as in periodontitis. Instead, the increased periodontal probing depth is due to the overgrowth of the gingiva. The presence of hyperplastic gingiva compromises tooth cleaning and may predispose to periodontitis. Radiography, to identify and thus treat concurrent periodontitis, is mandatory for patients with gingival hyperplasia.
Individuals with untreated gingivitis may develop periodontitis. The inflammatory reactions in periodontitis result in destruction of the periodontal ligament and alveolar bone. The result of untreated periodontitis is eventually exfoliation of the affected tooth. 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). Periodontitis can generally be considered 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.
Halitosis is common and is often the first sign noted by the pet owner. Large amounts of dental deposits are often present. These deposits need to be removed to allow a detailed examination of the periodontium. Ulcers affecting mucous membranes of lips and cheeks may be present in areas where these tissues are exposed to plaque-covered tooth surfaces.
Tissue destruction in periodontitis is assessed by measuring periodontal probing depth, gingival recession, furcation involvement and degree of tooth mobility. In many cases, measuring or calculating the periodontal attachment level (PAL) is also useful. Periodontal probing depth (PPD) is not necessarily correlated with severity of attachment loss. Gingival hyperplasia may contribute to a deep pocket (or pseudopocket if there is no attachment loss), while gingival recession may result in the absence of a pocket but also minimal remaining attachment. PAL records the distance from the cemento-enamel junction (CEJ) (or from a fixed point on the tooth) to the base or apical extension of the pathologic pocket. It is thus a more accurate assessment of tissue loss in periodontitis. PAL can either be measured with a periodontal probe or it can be calculated (e.g., PPD + gingival recession).
Radiography to assess the type and extent of alveolar bone destruction is mandatory for periodontitis patients. Consequently full mouth radiographs should be performed prior to the institution of any therapy. In addition, radiographs need to be taken at regular intervals to monitor outcome of any treatment. A detailed examination of the periodontal ligament space and interproximal alveolar margin requires the use of an intraoral radiographic technique. The radiographic changes associated with periodontal disease include resorption of the alveolar margin, widening of the periodontal space, a break in the path or loss of the radiopacity of the lamina dura and destruction of alveolar bone resulting in supra- or infrabony pockets.
Radiographs using a parallel technique will demonstrate more accurately the features of periodontitis because this technique provides a better view of the alveolar margin and reveals more accurately the actual extent or depth of the periodontal lesion in relation to the root of the tooth. Radiographs produced with a bisecting angle technique may show greater destruction of the alveolar bone than is actually present, because the central ray is directed obliquely to the long axis of the teeth and jaw, which produces dimensional distortion. Moreover, with the bisecting angle technique, subgingival calculus may be superimposed on alveolar bone and would thus not be detected. Views taken using a parallel technique will demonstrate deposits of subgingival calculus and defects of the cementum but may not cover a sufficient area to demonstrate extensive periodontitis lesions adequately. In the maxilla and anterior mandible, bisecting angle and parallel views of the same region may be required to visualize the extent of the tissue destruction more accurately.
Consequences to Affected Animal
Based on feedback from human patients, uncomplicated periodontitis is not associated with severe pain or discomfort. In contrast, complications such as the development of a lateral periodontal abscess or ulcers in the mucous membranes are very painful.
It has been shown that a severe infection in the oral cavity, as with extensive periodontitis, will lead to a transient bacteremia on chewing (Thoden van Velzen et al. 1984). In fact, an association has been demonstrated between periodontal disease and histopathologic changes in kidney, myocardium, and liver in the dog (DeBowes et al. 1996).
The treatment of periodontal disease has two components:
Maintenance of oral hygiene is performed by the owner and is often called home care. Its effectiveness depends on the motivation and technical ability of the owner and the cooperation of the animal.
Professional periodontal therapy is performed under general anesthesia and includes:
Supra- and subgingival scaling
Tooth crown polishing
And sometimes periodontal surgery
While it is essential to perform a thorough oral and dental examination to identify pathology and then treat it appropriately, the benefit of any professional periodontal therapy is short lived unless maintained by effective home care. In fact, if no home care is instituted after professional periodontal therapy, then plaque will rapidly reform and disease will progress. It has been shown that if no home care is instituted by three months after periodontal therapy, gingivitis scores are equivalent to those recorded prior to therapy (Gorrel, Bierer 1999).
However, the owner must realize that even with home care, most animals will still need to have their teeth cleaned professionally at intervals. The intervals between professional cleaning need to be determined for each animal. With good home care, the intervals between professional cleaning can be greatly extended. It is useful to draw an analogy to the situation in humans, i.e., most of us do brush our teeth daily but still require dental examinations and professional periodontal therapy (at a minimum scaling and polishing) at regular intervals.
References are available on request.