Radicular cyst & residual cyst

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



  • Proliferation of rests cells of Malassez

Common site

  • Maxillary anterior teeth (12, 21)


  • Regular, limited, buccal expansion

Peak age

  • 4-5th decade


  • 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



  • 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


  • 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)


  • 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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