• Affects any tooth
• When small – symptomless
• When large – expansion of alveolar bone + enlarge through sinus
• Seldom pain, unless inflamed and abscess formation

Etiology

• Dental caries
• Pulpal death due to trauma
• Restoration irritation
• Invaginated odontome

Pathology

• Proliferation of rests cells of Malassez

Common site

• Maxillary anterior teeth (12, 21)

Growth

• Regular, limited, buccal expansion

Peak age

• 4-5th decade

Clinical

• Slow progressing painless swelling, no symptoms unless infected
• Initial swelling is round
• When bone reduced to eggshell thickness – crackling on pressure
• When wall resorbed – soft fluctuant swelling, blue color, beneath mucous membrane

Radiology

• Round/ ovoid radiolucency at apex of tooth
• Dead pulp
• If pulp alive: Periapical cemental dysplasia

Histology

• Cyst wall:
  • Granulation tissue
  • Thick fibrous outer zone
  • Inflammatory cells infiltrate
  • Cholesterol clefts
  • Multinucleated giant cells
  • Vascular
• Epithelial lining:
  • Non keratinized stratified squamous epithelium (absent in some places)
  • Hyperplastic
  • Arcading rete pegs
  • ± Goblet cells (mucous metaplasia)
  • Rushton bodies
• Lumen:
  • Serous exudate (pale pink)
  • Macrophages (foamy)
  • Cholesterol clefts

Management

• Non surgical: RCT
• Surgical:
  • Enucleation (remove whole cyst)
  • Marsupialization (suture ends of cyst to external surface)
  • Decompression (small opening in cyst and drain)
  • Apicectomy (tooth’s root tip removed)

Recurrence

• Rare
• Residual cyst if retained after extraction of tooth

NB: Lateral type rare, Due to inflammation of pulp extending into lateral periodontium along lateral root canal

Residual cyst

• 20% of radicular cyst – persists after extraction of causative tooth
• Common cause of swelling in edentulous jaws in old people
• Interferes with fitting of dentures but regresses spontaneously

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