Periodontal Disease

Typical Signalment

• Pure bred cats are particularly susceptible and include:
  • Persian
  • Maine Coon
  • Burmese
  • Siamese
• Affects majority of cats over two years of age.
• Certain breeds of dogs are thought to be susceptible to an aggressive form of the disease including:
  • Greyhounds
  • Maltese dogs
• Small breed dogs are more prone to tooth crowding, predisposing the animal to the initiation and rapid progression of the disease

Description

Periodontal disease is essentially an inflammatory response by the supporting structures of the teeth known as the periodontium. These structures include:

• gingiva
• periodontal ligaments
• cementum
• alveolar bone

It is the most common dental disease in dogs and cats and the major cause of tooth loss in both species. There are numerous factors that contribute to the formation of the disease but the primary agent is dental plaque. Plaque accumulates at the gingival margin, partly due to insufficient oral hygiene.

Initially the bacterial flora tend to be non-motile aerobes or facultative anaerobes. However, as the supply of oxygen is reduced by supragingival plaque accumulation and pocket formation, the bacterial flora become more motile and anaerobic. Important bacterial flora responsible include:

• Porphyromonas gingivalis
• Bacterioides asaccharolyticus
• Fusobacterium nucleatum
• Actinomyces viscosus
• Actinomyces odontolyticus

Gingivitis and periodontitis are the two main forms of the disease. Gingivitis is the early form of the disease and often but not always progresses to periodontitis.

• Gingivitis - Reversible inflammation of the marginal gingival tissues that does not affect the periodontal ligament or the alveolar bone.

• Periodontitis - Inflammation and irreversible destruction of the tooth's supporting structures that includes the gingiva, periodontal ligament, alveolar bone and root cementum. It usually occurs after years of plaque acculmulation and gingivitis. The epithelial attachments of the tooth regress apically and there is absorption of the associated alveolar bone, resulting in permanent loss of tooth support.

Diagnosis

Clinical Signs

• fetid breathe odour (Halitosis)
• excessive salivation
• blood in saliva
• dysphagia
• pain on mastication
• difficulty eating
• loose teeth
• lethargy
• weight loss
• poor grooming

Oral Examination

This is the most important part of the diagnostic procedure and should include inspection of the following:

• Extraoral structures (looking for swelling, atrophy or assymmetry)
  • face
  • lips
  • muscles of mastication
  • temporomandibular joints
  • salivary glands
  • lymph nodes
  • maxillae
  • mandibles
• Intraoral structures
  • dentition
  • gingiva
  • mucosa
  • tongue
  • tonsils
  • occlusion

On visual inspection of the intraoral structures, an animal with periodontitis may demonstrate the following:

• oral mucosal ulceration
• inflammed and bleeding gingiva
• loss of normal gingival contour
• purulent discharge from periodontal pocket
• gingival recession
• loose teeth
• variable quantities of plaque and calculus on the tooth surface

Periodontal Examination

A thorough periodontal examination of dogs should always be performed under general anaesthesia. The examination under general anaesthesia in cats allows a more detailed evaluation of the oral cavity.

The periodontal examination is performed using a periodontal probe which is gently run under the gingival margin of each tooth. An evaluation is made of the following:

• amount of plaque and calculus present on the tooth surface
• degree of gingivitis
• presence of gingival hyperplasia or recession
• degree of attachment loss
• boney resorption at the furcation
• mobility of individual teeth

The disease can then be staged:

• Stage 0 - Normal and healthy periodontium
• Stage 1 - Periodontal disease/Gingivitis (0% attachment loss, Pocket depth <0.5mm)

Diagnostic Imaging

Oral radiography can be used to assess periodontitis. Cases of periodontitis will show generalised horizontal and vertical alveolar bone loss in focal areas.

Radiographic signs of periodontitis:

• resorption of the alveolar margin
• widening of the periodontal ligament space
• loss of the lamina dura (cortical bone of the alveolus)
• alveolar bone destruction

Treatment

The suspected cause of the condition should be corrected first. This may include a multimodal treatment plan aimed at controlling plaque formation including teeth brushing and providing the animal with sticks/toys that clean the teeth crowns

• Gingivectomy and gingivoplasty - should be carried out under general anaesthetic if significant pseudo-pockets are present between the gingiva and teeth crowns. The aim should be to eliminate the pseudopockets and re-establish the normal anatomy of the gingival margin.
  • Electrosurgery and Laser surgery - care must be taken with electrosurgery to avoid contact between the teeth crowns and the electrodes to prevent irreversible heat damage to the pulp.

References

• Tutt, C., Deeprose, J. and Crossley, D. (2007) BSAVA Manual of Canine and Feline Dentistry (3rd Edition) BSAVA

• Merck & Co (2008) The Merck Veterinary Manual