35 Tooth Root Abscess (Apical Abscess)


  • An abscess is a localized collection of pus in a cavity formed by the disintegration of tissues
  • Accumulation of inflammatory cells at the apex of a nonvital tooth: periapical abscess (Fig. 35-1)

x25AA001rs Figure 35-1 Collection of purulent tissue at the apex of a nonvital tooth at extraction.



  • Can divide into “acute” and chronic phases on the basis of severity of pain and presence or absence of systemic signs and symptoms
  • Acute exacerbation of a chronic periapical abscess is called a phoenix abscess
  • An abscess spreads along the pathway of least resistance from the tooth apex, resulting in osteomyelitis if perforated through the cortical bone, a cellulitis that can result in extension into a draining tract

    • Opening through the skin to create a cutaneous sinus (Fig. 35-2)
    • Opening through the alveolar mucosa, often at or apical to the mucogingival junction

  • Systemic spread of bacteria (bacteremia and pyemia) can affect other organ systems
  • Periodontal disease can extend to the apical region of the tooth resulting in endodontic involvement (perio-endo lesion)
  • Potential causes

    • Any pulpal trauma
    • Direct blow causing fracture of the crown of severe pulpitis and pulpal necrosis
    • Defense (fighting): the canines are most commonly affected
    • Chewing hard objects (e.g., bones, hooves, rocks, wood, especially with knots): carnassials are most commonly affected
    • Malocclusive trauma
    • “Tugging” rags with puppies
    • Previous surgical repair to an area around the dentition: bone plating for fracture repair
    • Bacteria: the pulp can be affected by bacteria from dental caries, exposed dentinal tubules
    • A deep periodontal pocket, especially at the palatal root of a small dog, can encompass the apex and bacteria can enter the pulp through the apex
    • Septicemia: documented in humans but not yet proven in animals
    • Thermal heat resulting in pulpal necrosis: electrical cord burns
    • Diabetes or Cushing’s disease
    • Radiation necrosis

x25AA001rs Figure 35-2 Typical appearance of infraorbital abscess with draining tract opening below the eye: likely an extension of apical abscess and should be fully evaluated.



  • Dogs and cats
  • Can occur in deciduous and permanent dentition
  • Usually occurs in active animals that bite or chew a lot or chase objects (balls, cars, etc.)
  • Can involve any tooth; canines (trauma) and carnassial teeth (iatrogenic chewing) are most commonly affected


  • Tooth is visibly broken: 90% of cases

    • Malocclusive trauma where there is constant trauma to the tooth is the exception

  • Tooth may only be cracked with pulp or near pulp exposure
  • Tooth may appear discolored
  • Tooth is not sensitive to cold or hot liquids or foods

    • Note: acute tooth fracture with pulp exposure would be sensitive

  • Facial swelling: usually localized but can spread, resulting in a cellulitis (Fig. 35-3)
  • Draining tract exuding purulent material

    • Cutaneous: below the eye (infraorbital abscess)
    • Opening through the alveolar mucosa, often at or apical to the mucogingival junction (mucosa draining tract coronal to the mucogingival junction would likely be periodontal in origin) (Fig. 35-4)

  • Facial sensitivity may be slight, but could be extensive if there is no drainage
  • Increased accumulation of plaque and calculus on the affected side of the mouth
  • Animal does not want to chew, especially on the affected side (plaque and calculus may accumulate more extensively)
  • Animal may be head-shy
  • Animal may bite but will release quickly instead of holding on
  • Tooth may be asymptomatic for a long time but will be affected sooner or later
  • Tooth may be clinically asymptomatic, yet nonapparent problems, such as bacteremia, may be occurring.
  • Tooth may be sensitive to percussion
  • A deep vertical periodontal pocket may extend to the apex of the affected tooth, or may be formed from an extension from the apical infection (endo-perio lesion)
  • Putrid smell
  • Tooth may be loose and painful on palpation
  • May have facial lymphadenitis
  • Sinusitis: maxillary sinus is most commonly affected
  • Sense of smell may be affected, especially with working dogs (drug or bomb-sniffing)

May 22, 2017 | Posted by in GENERAL | Comments Off on 35 Tooth Root Abscess (Apical Abscess)
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