Pathology of Periapical Periodontitis

• Learning outcomes:

  
• What is periapical periodontitis?

  Inflammation of periodontal ligament and other tissues around tooth apex
• What are the causes of periapical periodontitis?

  Usually due to spread of infection following death of the pulp

  
  

  Extrusion of antiseptics through apex during root canal treatment

  
  

  A high filling or biting suddenly on a hard object sometimes causes an acute, usually transient, periapical periodontitis
• What tends to be the clinical findings associated with acute periapical periodontitis?

  History of pulpitis

  
  

  Escape of exudate into periodontal ligament causes a small amount of tooth extrusion

  
  

  Pain well localised: Tender to touch/percussion

  
  

  Tooth not vital & not responsive to vitality tests unless pulpal necrosis limited to single canal in multirooted tooth

  
  

  As inflammation becomes more severe, there can be intense throbbing pain

  
  

  Infection usually remains localised

  
  

  Abscess can develop

  
  

  Can spread in tissue planes causing facial swelling Rarely local lymphadenopathy

  
  

  Very rarely, osteomyelitis or cellulitis

  
• What can you see radiologically & pathologically relating to acute periapical periodontitis?

  Radiology: bone resorption not had time to happen so only radiographic change may be widening of periodontal ligament space

  
  

  Pathology: acute inflammation i.e presence of neutrophils
• How would you manage acute periapical periodontitis?

  Endodontic treatment

  
  

  Extraction

  
  

  Open drainage through skin or mouth if needed due to abscess causing swelling
• What are the clinical signs relating to chronic periapical periodontitis?

  - Low grade infection

  
  

  - May follow acute periapical periodontitis

  
  

  - Tooth is not vital, unless very rarely pulpal necrosis is limited to a single canal in a multi-rooted tooth.

  
  

  - Symptoms may be minimal

  
  

  -Can be tender to percussion

  
• What are the radiological signs of chronic periapical periodontitis?

  -Often diagnosed on identification of a periapical radiolucency
• What is the pathology of chronic periapical periodontitis like?

  -Chronic inflammation and granulation tissue
• What are the sequelae of chronic periapical periodontitis?

  Periapical granuloma and in some cases, subsequently radicular cyst

  
  

  Acute exacerbation with suppuration/abscess, cellulitis and sinus formation

  
  

  Very rarely, focal sclerosing osteitis

  
• How do you treat chronic periapical periodontitis?

  Extraction or root canal treatment

  
  

  A radicular cyst may need to be enucleated (removal)
• What are some features of periapical granulomas and how does it affect the tooth?

  Most asymptomatic

  
  

  May be history of pulpitis

  
  

  But can have coexisting pulpitis and therefore be symptomatic

  
  

  Tooth is not vital and will not be responsive to vitality tests unless the pulpal necrosis is limited to a single canal in a multirooted tooth

  
• What are some radiographic features of periapical granulomas?

  
• What is important to remember about a periapical granuloma?

  A periapical granuloma isNOTgranulomatous inflammation so don't get them confused!

  
• What would you pathologically see regarding a periapical granuloma?


  See chronically inflamed granulation tissue at apex of a nonvital tooth

  
  

  Defensive reaction secondary to the presence of bacteria in the root canal with spread of related toxins into the apical zone

  
• What is the relation of periapical granulomas to apical scars?


  It's a defect created by periapical inflammatory lesions, may rarely heal by filling with dense fibrous tissue rather than normal bone

  
  

  These fibrous periapical scars occur most frequently when both the facial and lingual cortical plates have been lost
• What is the relation of periapical granulomas to apical abscesses?

  Periapical granulomas may arise after quiescence of a periapical abscess or may develop as the initial periapical pathology
• What is a cyst?

  An epithelial-lined cavity
• What is the relation of periapical granulomas to radicular cysts?

  Cell rests of Malassez (epithelial remnants from tooth development) lying in vicinity of periapical area may show reactive proliferation to inflammation / infection leading a radicular cyst
• What is focal sclerosing osteitis?

  Very rare condition which is most frequent in children & young adults but can occur in older people

  
  

  It's localised, usually uniform bone sclerosis (radiodense) adjacent to tooth apex of a tooth with periapical periodontitis

  
  

  And most occur in lower premolar and molar areas
• What can focal sclerosing osteitis resemble?

  Several other intrabony lesions
• How does focal sclerosing osteitis usually progress?

  85% of cases of focal sclerosing osteitis will regress, either partially or totally, after root canal treatment or tooth extraction

  
  

  A residual area of condensing osteitis that remains after resolution of the inflammatory focus is termed a bone scar