DEFINITION/OVERVIEW
- 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)
ETIOLOGY/PATHOPHYSIOLOGY
- 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
- Opening through the skin to create a cutaneous sinus (Fig. 35-2)
- 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
- Any pulpal trauma
SIGNALMENT/HISTORY
- 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
CLINICAL FEATURES
- 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)
- Cutaneous: below the eye (infraorbital abscess)
- 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)