- Radicular cysts are the most common type of cyst, occurring at the apex of a nonvital tooth with necrotic pulp. They appear on radiographs as well-defined, radiolucent lesions with a curved outline located at the apex of a tooth root. - Dentigerous cysts are the second most common type of cyst, occurring around the crown of an unerupted tooth. On radiographs they appear as well-defined, radiolucent lesions with a curved, circular outline that is attached to the cementoenamel junction of an unerupted tooth. - SBCs (simple bone cysts) occur more commonly in the mandibular ra

1. CystsYasaman sherafatmand

3. Radicular cyst
• Disease mechanism
Inflammatory products of nonvital tooth
• Clinical features
Most common cyst
Necrotic pulp
Swelling and crepitant

4. RADIOGRAPHIC FEATURES

5. location
• Apex of a nonvital tooth
• Mesial or distal of a tooth root
• Deep periodontal pocket
• 60% maxilla (incisor and canine )
• Expansion of cysts around latral tooth
into antrum
• Deciduous molar positioned buccal

6. Periphery and shape
Well defined
corticated
Curved and circular
Secondarily infected :
Sclerotic
Loss of cortex

7. Secondry infected Peripheral cortex

8. Internal structure
• Radioluscent
• Dystrophic
calcification

9. Effects on surrounding
structures
• Displacement and resorption of root
with curved outline
• Invagination in sinus
• Inferior displacement of alveolar
nerve canal

10. Healing radicular cyst
after RCT

11. DDX
• Apical granuloma : 2cm> , ill defined
blending
• PCD : History
• OKC : vitality test
• Ossifying fibroma : epicentral opacities
• Benign fibro osseous

13. Residual cyst
• Cyst that remains after removal of
original cyst
• Asymptomatic
• In edentulous area

14. RADIOGRAPHIC FEATURES

15. Location
• Man > max
• Epicenter above the
I.A.C
Periphery
• Well defined
corticated
• Secondarily infected
...
• Oval or circular

16. Internal structure
• radiolucent
Effects on surrounding
structures
• Displacement and
resorption of root with
curved outline
• Invagination in sinus
• Inferior displacement of
alveolar nerve canal

17. DDX
• KOT : less expansion
• Stafne : below the mandibular canal

19. Dentigerous cyst
• Around the crown of an unerupted
tooth
• Fluid between reduced enamel
epithelium layers or between
epithelium and the crown
• Eruption cyst

20. Clinical features
• The second most common cyst
• Around the crown of an unerupted
tooth or supernumerary
• Missing tooth or hard swelling
• No pain

21. RADIOGRAPHIC FEATURES

22. location
• 3rd molar of man or
max
• Maxillary canine
• Attached to CEJ

23. Periphery and shape
• Well defined
corticated
• Curved and
circular outline

24. Internal structure
• radioluscent

25. Effects on surrounding
structures
• Displacement
(apically) and
resorption of root
• Canine and 3rd molar
of max to floor of orbit
• 3rd molar of man to
condyl, coronoid
process , inferior
cortex of mandible

26. DDX
• Hyperplastic follicle : without tooth
displacement , <2-3mm
• KOT : less expansion , not attached to
CEJ
• AOT : radio opaque
• Radicular : deep caries
• Ameloblastic fibroma
• Cystic ameloblastoma

28. SBC
• Intra bony
• Not a true cyst
• Inside cemento-osseous dysplasia and
fibros dysplasia

29. Clinical features
• Firs 2 decades
• m/f : 2/1
• with cemento-osseouse dysplasia in older
population and m/f = ¼
• Asymptomatic
• Vital tooth
• Straw color or serosanguineous aspiration

30. RADIOGRAPHIC FEATURES

31. location
• Mandible
• Older people : ramus
and posterior
mandible

32. Periphery and shape
• Well defined
corticated to ill
defined
• Better defined in
alveolar process than
the inferior aspect

34. Internal structure
• Radioluscent
• Mulilocular
• Scallop in latral view

35. Effects on surrounding
structures
• No effect on teeth
• Intact lamina dura
• Extension >
expansion
• Scallop the
endosteal surface
of outer cortex

36. DDX
• KOT : more corticated periphery,
displacement of tooth , older population
• Malignancies
Biopsy : ossifying fibroma
fibrous dysplasia