Periodontology (Proceedings)

Diagnosis

The periodontium is made up of the gingiva, the periodontal ligament(PDL), cementum and alveolar bone. The gingiva attaches in the form of a collar around the neck of the tooth. Coronal to the attached gingiva is a free margin called unattached gingiva. The distance from the coronal margin of the gingiva to the attached portion is called the sulcus. A normal sulcus in the dog is 0 to 3 mm. A normal sulcus in the cat is 0 to 0.5 mm. Gingivitis is an inflammation of the gingiva. Periodontitis is an active disease state of the structures that make up the periodontium. Periodontal disease refers to the altered state of the periodontium with or without active disease. Therefore, an animal may have periodontal disease but not an active state of periodontitis. Periodontitis usually develops from gingivitis creating an attachment loss of the gingiva. The percent attachment loss(PAL) can be measured with the periodontal probe. Measurements beyond the normal sulcus depths are called periodontal pockets. When the loss of gingival attachment progresses the alveolar bone is involved. Bone lysis follows with involvement of the PDL and cementum. Pockets that do not involve bone are called supraboney pockets. When bone is lost, infraboney pockets are formed often called vertical bone loss. If bone is lost in a more generalized fashion, the condition is referred to a horizontal bone loss. Indices are used in periodontal disease to score plaque, gingival inflammation, sulcus bleeding, calculus, radiographic bone lysis and PAL. A veterinary periodontal index is used to score the stage of disease. A table for staging is listed in VDPP page 198.

The cause periodontal disease is plaque. Plaque is a white to yellow to grey colored stratified biofilm composed of salivary glycoproteins, oral bacteria, and extracellular polysaccharides. The polysaccharides account for a carbohydrate composition of approximately 30%. The most common carbohydrate of plaque is dextran. The carbohydrates of plaque form an excellent substrate for bacterial growth. Plaque is stratified in different bacterial layers supragingivally and descending into the periodontal pocket. The bacteria in supragingival and subgingival plaque is similar in the healthy gingiva. The microflora is composed primarily of aerobic and facultative anaerobic bacteria, mostly Gram positive, nonmotile, aerobic bacteria. As gingival health decreases and pocket depth increases, the flora becomes more Gram negative, anaerobic, motile, with rod and filamentous shape. Bacteria in healthy gingiva of dogs is

about 25% rod bacteria, while in periodontitis it becomes 95% of the microfloral population. Some common periodontal pathogens are: Porphyromonas, Bacteroides(pigment forming), Fusobacterium, Prevotella, and Spirochettes. The byproducts of these bacteria produce significant inflammation to the surrounding tissue by way of chemotoxins, mitogens, antigens and enzymes. These products stimulate the migration of polymorphonuclear granulocytes to the area, affect an immune response and cause direct tissue damage. Understanding the mediators of inflammation will enhance the therapy for this disease. Plaque will harden into calculus on the surface and in the superficial layers. The calculus has a combined effect by way of protecting the deeper layers of anaerobic bacteria from oxygen and creating an irritation to the gingiva. Gingivitis can develop in as little as 2 to 4 days with 4 to 14 days to develop periodontitis. There a two theories related to plaque/periodontitis. The specific plaque hypothesis says the disease is caused by specific strains of virulent organisms. This usually is a more rapid onset disease. The nonspecific plaque hypothesis says there is a superinfection of a mixed bacterial population and a lack of a host immune response. This is usually a slower onset, smoldering disease.

Periodontitis is categorized by the time and progression of disease in the animal. There are various forms of periodontitis: prepubertal(PP)-or early onset, adult(AP) , localized juvenile(LJP)-or early onset but limited to location, rapidly progressive(RPP)-or aggressive, and refractory rapidly progressive(RRPP)-or necrotizing. The disease periodontitis can be subclassified into three major types: Chronic, Aggressive and As Manifested by Systemic Disease. In general, small dogs are much more likely to have periodontal disease than large dogs. Some breeds are more likely to have a certain form of the disease than others. The following applies:

     • PP - Abyssinian and Somali cats.

     • AP - seen in all breeds and species.

     • LJP - miniature Schnauzer and greyhound dogs.

     • RPP - seen more in young adults, Lhasa apso, Shi Tzu,

           o Yorkshire terrier, greyhound, Maltese dogs, and

           o Abyssinian and Somali cats.

     • RRPP - greyhound, Maltese, miniature Schnauzer dogs

     • and Abyssinian and Somali cats (see LPGS under feline diseases). Associated with chronic ulcerative paradental stomatitis (CUPS).

Treatment and prevention

The best means of treatment of this disease is to prevent it from occurring. Frequent dental examination, prophylaxis and home-care are most important. As with most diseases, early intervention will give the easiest and most successful treatment. Before any treatment is decided, it is important to understand the clients dedication and ability to treat periodontitis at home. If the patient or the owner will not allow meticulous oral home care, extraction must be considered. If the owners of the animal can provide excellent home-care, the treatment is based on the stage of disease.

Stage 1

Examination and prophy every 6 months. Daily home care with oral brushing and dentifrice. Chew items.

Stage 2

Examination every 3 months and prophy as indicated. Closed root planing and currettage. Use of periodontal absorbable antibiotic resin (Doxirobe Therapeutic), Antibiotics preoperatively and following for 10 days. Recheck in 7 to 10 days. Daily home care with Chlorhexidine brushing gel and rinse. Chew items. Daily NSAID and eicosanoids.

Stage 3 & 4

Surgical (open) root planing, curettage with prophy, possibly bone augmentation with guided tissue regeneration (using an osseoconductive agent like Consil and a impermeable membrane). Antibiotics pre-operatively and following for 14 to 28 days. Recheck in 14 days then in 1 month. Once condition is controlled recheck every 3 months. Daily home care with Chlorhexidine brushing gel and rinse. Pulse antibiotic therapy for 5 days of each month. Daily NSAID and eicosanoids. The antibiotic of choice for periodontitis in the dog and cat is either clindamycin or amoxicillin/clavulanate. Other antibiotic that have shown a good response are doxycycline and metronidazole.

Periodontitis is the most common disease seen in small animal practice. One study indicated that the disease was seen in 80% of the dogs and 70% of the cats with ages ranging from 20 to 27 months of age. The incidence of this disease increases with age. A much higher incidence is expected in older animals.