Periodontal disease-a primer on recognition and therapy

Periodontal disease-a primer on recognition and therapy

Jan 01, 2004

Periodontal inflammation is the most common syndrome affecting small animals. In no other area of the body can the dedicated veterinarian and dental team make a lifelong difference in patient health and longevity.

AnatomyThe term periodontium describes tissues that surround and support the teeth including the gingiva, alveolar bone, periodontal ligament, and cementum.

In the dog, the healthy free gingival margin of premolars and molars is 1-2 mm coronal (toward the crown) to the cementoenamel junction (CEJ), where root cementum meets the enamel. In the feline, the free gingival margin is 0.5 mm to 1 mm coronal to the CEJ. The attached gingiva is located apical (toward the tooth root) to the marginal gingiva and normally is tightly bound to the alveolar crest and the periosteum of alveolar bone. The width of the attached gingiva varies in different areas of the mouth. Attached gingiva is keratinized to withstand the stress of ripping and tearing. The connection of firm attached gingiva with loose alveolar mucosa is the mucogingival junction (MGJ), also called the mucogingival line (MGL). The mucogingival junction remains stationary throughout life although the gingiva around it may change in height due to hyperplasia, recession or attachment loss.

Plaque and calculusWithin 20 minutes of teeth cleaning, a glycoprotein layer (acquired pellicle) attaches to the exposed crown. Within 6 hours, bacterial colonization (plaque) forms on the glycoprotein layer. In some patients, plaque irritates the gingiva, allowing pathogenic gram-negative bacteria to survive subgingivally. By-products of these bacteria stimulate the host's immune response to release cytokines and prostaglandins that weaken and destroy the tooth's support. The progression of periodontal disease is dependent on the regulatory interaction between bacteria and immune modulators of the host response.

Calculus (tartar) plays a role in maintaining and accelerating periodontal disease by keeping plaque in close contact with gingival tissues, decreasing the potential for repair and new attachment. The therapeutic importance of removing all calculus during the professional oral hygiene visit cannot be overemphasized.

Photo 1: Stage 1 early gingivitis in the maxillary fourth premolar.
Four stagesThere are numerous grading systems used to classify gingivitis and periodontal disease. Generally, gingivitis is used to describe soft tissue inflammatory changes. Periodontitis is diagnosed when attachment loss has occurred. The patient can be "graded" by the worst tooth (i.e., if there is one stage 4 area, the patient has stage 4 disease). After the disease has been treated, the patient can be upgraded.

Stage 1 (gingivitis) appears as gingival inflammation at the free gingival margin. As gingivitis progresses, advanced gingivitis appears as gingival inflammation, edema, and bleeding on probing. Advanced gingivitis is limited to the epithelium and gingival connective tissue. There is no tooth mobility or attachment loss. Gingivitis is reversible with proper initial therapy and aftercare at home (Photo 1).

Photo 2: Stage 2 early periodontitis in the maxillary fourth premolar. Note slight gingival recession.
Stage 2 (early periodontitis) occurs when there is apical migration of the junctional epithelium, resulting in a deeper sulcus called a pocket, or gingival recession. In stage 2 disease, up to 25 percent attachment loss occurs (Photo 2 ).

Stage 3 (established periodontitis) is present when 25 percent to 50 percent attachment loss exists around a root. Slight tooth mobility occurs in single-rooted teeth. Early furcation exposure at the trunk of multirooted teeth and/or gingival recession may exist (Photos 3 and 3a).

Photo 3: Stage 3 established periodontitis in the maxillary fourth premolar and Photo 3a: Stage 3 furcation exposure in the maxillary fourth premolar.
Stage 4 (advanced periodontitis) presents when marked (greater than 50 percent) attachment loss occurs. Stage 4 periodontal disease can appear as furcation exposure, abscess formation, tooth mobility, deep pockets, and/or gingival recession (Photo 4).

Gingival hyperplasia Abnormal proliferation of the gingiva is termed gingival hyperplasia. The boxer breed is more prone than others to be affected by gingival hyperplasia. Gingival hyperplasia results in increased pocket depths, caused by increased gingival height, not attachment loss. The resultant pseudopocket can accumulate plaque, which, if untreated, may progress to attachment loss. Gingival hyperplasia is treated by gingivectomy and strict home care to help prevent recurrence.

Photo 4: Stage 4 calculus and marked gingival recession in Stage 4 periodontitis.
Radiographic appearanceIntraoral radiography provides critical information when making periodontal therapy decisions by imaging the supportive bone mesial (rostral) and distal to the affected teeth.

If clinically and radiographically greater than 50 percent of the bone and tooth support remains, periodontal procedures together with a healthy patient and stringent home care will often result in a saved tooth. A guarded prognosis is given when 50 percent to 75 percent bone loss exists. If greater than 75 percent support is lost, the prognosis for saving the tooth is poor (Photos 5-7).

Periodontal probingA periodontal probe is the single most important examination instrument used to evaluate periodontal health. By gently inserting a calibrated periodontal probe just apical to the free gingival margin and tracing the gingival crevice from mesial to distal, a rapid determination of the health of the sulcular tissues can be made.

Photo 5: Normal appearing radiograph of the maxillary first molar in a dog with gingivitis, Photo 6: Radiograph of stage 2 disease with 4 mm pocket (periodontal probe inserted), Photo 7: Furcation involvement and exposure in a dog's mandibular third, fourth premolars and first molar.
The probe stops where the gingiva attaches to the tooth or at the apex of the alveolus if attachment is lost. Each tooth should be probed on a minimum of four sides. Bleeding on probing is indicative of an inflammatory process in the connective tissue adjacent to the junctional epithelium. If the sulcular lining is intact and healthy, no bleeding will occur. If, however, periodontal disease is present, bleeding will usually take place.

Normal dogs should have less than 2 mm probing depths, and cats less than 1 mm. Abnormal probing depths are noted on the dental record and discussed with the client, before a treatment plan can be formulated.

PocketsThe clinical sulcus is the distance from free gingival margin to the most apical point that a probe reaches when gently inserted into the gingival crevice. Pockets that result from attachment loss are called periodontal pockets. The periodontal pocket is a pathologically deepened gingival sulcus. The clinical (absolute) pocket depth is the distance from the free gingival margin edge to the base of a pocket, measured in millimeters.

Attachment loss (attachment level) is used to evaluate support loss in cases of gingival recession where little or no pocketing exists. The measurement of attachment loss is the backbone of a periodontal examination. The clinical pocket depth plus recession (measured CEJ to free gingival margin) equals the total periodontal attachment loss.

Therapy of periodontal diseasePeriodontal care includes supragingival and subgingival scaling, application of local medication, bone graft implants, periodontal flap surgery, extraction and home care.

Stage 1 gingivitis care includes thorough supra and subgingival teeth cleaning and polishing, followed by daily brushing. Gingivitis will usually resolve within weeks of the oral hygiene visit.

Image 1: Drawing of periodontal pocket before antibiotic insertion.
Stage 2 early periodontal disease, where minimal to moderate pockets are diagnosed, can be treated similarly to stage 1 disease +/- root planing, +/- local administration of an antibiotic (LAA). Doxirobeª Gel (Pfizer) contains a flowable biodegradable solution of 8.5% doxycycline hyclate, which is applied subgingivally to cleaned periodontal pockets greater than 3 mm in dogs older than 1 year.