Canis ISSN: 2398-2942

Periodontal disease

Synonym(s): Gum disease, gingivitis, periodontitis

Contributor(s): Susanna Penman, MarkThompson, Matthew Oxford

Introduction

  • Active plaque is the cause of periodontal disease.
  • Plaque is a biofilm of salivary proteins and oral bacteria which adheres to the exposed tooth surface. Plaque is a very stable environment, which can be affected only very minimally by chemicals such as disinfectants and antibiotics. Plaque elimination requires mechanical removal.
  • If plaque persists for a prolonged period it can become calcified to form calculus Teeth: calculus. Calculus is a largely inert material, however it has two factors that promote the progression of periodontal disease. It increases surface area, which is rough and aids plaque deposition. It accumulates around the gingival margin, reducing oxygen tension here and promotes the proliferation of anaerobic bacteria. It is these that are presumed to be responsible for the progression from gingivitis to periodontitis .
  • Periodontal disease is one of the most common disease processes seen in domestic pets, affecting 70% of adult dogs and cats.
  • Cause: bacterial plaque.
  • Signs: halitosis, dysphagia (especially hard food), hypersalivation (possibly with blood streaks from bleeding gums), rubbing mouth on ground or with paws, general malaise, spontaneous (pathological) mandibular fracture, eg Yorkshire Terrier with advanced peridontal disease.
  • Diagnosis: signs.
  • Prognosis: depends on owner compliance.
  • Treatment: scale and polish, meticulous subgingival scaling, selective extraction, prevention of recurrence; dietary modification.
    Follow the diagnostic trees for Halitosis Halitosis and Periodontal staging Periodontal Staging.
Use the interactive tool from ROYAL CANIN® UK  to explain dog anatomy and disease conditions to your client. Visit ROYAL CANIN Natom Explorer to find out more.​

Pathogenesis

Etiology

  • Active plaque is the cause of periodontal disease.
  • Plaque is a biofilm of salivary proteins and oral bacteria which adheres to the exposed tooth surface. Plaque is a very stable environment, which can be affected only very minimally by chemicals such as disinfectants and antibiotics. Plaque elimination requires mechanical removal.
  • If plaque persists for a prolonged period it can become calcified to form calculus Teeth: calculus. Calculus is a largely inert material, however it has two factors that promote the progression of periodontal disease. It increases surface area, which is rough and aids plaque deposition. It accumulates around the gingiva margin, reducing oxygen tension here and promotes the proliferation of anaerobic bacteria. It is these that are presumed to be responsible for the progression from gingivitis to periodontitis .

Predisposing factors

General
  • Ineffective home care.
  • Possible genetic susceptibility.
  • Systemic disease.

Specific

  • Existing calculus (mineralized plaque) with rough surface aiding accumulation of more plaque.

Pathophysiology

  • Endotoxin released from bacteria within plaque irritates the gingivae and causes a localized inflammatory reaction.
  • Oral bacteria sticks to pellicle (thin protein layer coating all exposed tooth surfaces) to form supragingival plaque (non-motile, aerobic, gram-positive cocci and rods). With time, plaque will mineralize to form calculus.
  • Normal animal's natural defense mechanisms protect underlying tissues from bacterial invasion (gingivitis). At this stage, periodontal disease is reversible by regular removal of plaque through tooth brushing.
  • Pathological: as calculus forms, the oxygen tension within the gingival sulcus changes, promoting the proliferation of anaerobic organisms. It is this switch that leads to the progression of periodontal disease. Inflammatory mediators released in response to the anaerobes promote osteolysis which will cause alveolar bone loss. This may lead to gingival recession or periodontal pocket formation or a combination of both. As the epithelial attachment recedes apically, alveolar bone loss exposes the root surface and the cementum layer. Cementum is rough which promotes in turn greater plaque and calculus deposition as subgingival accumulations. This then further promotes alveolar bone loss in spiralling progression. This is periodontitis, and it is irreverible. It can however be managed and its progression prevented with good professional therapy followed by good home care.
  • Gingival hyperplasia Gingival enlargement is an alternative response to periodontal disease .
  • If the full thickness of alveolar bone is destroyed bone loss proceeds horizontally from the alveolar crest. In this case, the epithelial attachment usually remains coronal to remaining alveolar bone, forming a suprabony pocket. With horizontal bone loss the gingival margin often recedes wiht the epithelial attachment which gives periodontitis without pocket formation, known as gingival recession.
  • If a partial thickness of alveolar bone is destroyed, especially along the root surface, this is called vertical bone loss. In this case, the epithelial attachment often recedes apically beyond the crest of remaining alveolar bone, forming an infrabony pocket. This is a periodontal pocket and owing to the reduced oxygen tension in the pocket, will rapidly progress to deep pocket formation, often exuding pus. Periodontal pockets are harder to manage than gingival recession.
  • The tooth will become mobile when >50% periodontium destroyed. This will weaken the remaining periodontal ligament even more, and most significantly, the periodontal disease will now become significantly more painful for the patient. As the tooth moves within the alveolus, there is stimulation of nerves within the periodontal ligament and at the apex of the tooth supplying the pulp.
  • Eventually the tooth will be exfoliated, taking majority of bacteria with it.
  • The alveolus will then heal slowly with sclerotic bone (3-6 months).

Timecourse

  • Variable (dependent on presence of predisposing factors).
  • Over 70% of adult dogs and cats have periodontal disease that would benefit from treatment.
  • Periodontal disease is not a linear disease, but waxes and wanes depending on the predisposing factors and the host response. The rate of progression of periodontal disease will depend on these factors.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Gorrel C (1998) Periodontal disease and diet in domestic pets. J Nutr 128 (12 Suppl), 2712S-2714S PubMed.
  • Harvey C E et al (1996) Correlation of diet, other chewing activities and periodontal disease in North American client-owned dogs. J Vet Dent 13 (3), 101-105 PubMed.


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