odontogenic cysts

Question 1

What is a cyst?

Answer 1

Pathological cavity filled wholly or partly by epithelium and contains fluid or semi fluid contents

Question 2

Name 2 types of inflammatory cysts?

Answer 2

Radicular

Residual

Question 3

Name 4 types of developmental cysts?

Answer 3

Odontogenic keratocyst 
Dentigerous cysts
Eruption cyst
Lateral periodontal cyst
Gingival cyst
Calcifying odontogenic cyst

Question 4

Name 4 non odontogenic cysts?

Answer 4

Nasopalatine
Nasolabial
Stafne bone cyst
Aneurysmal bone cyst

Question 5

Radicular cysts:

Explain where they are derived from, clinical and radiology signs and treatment options?

Answer 5

Aetiology:

• derived from cell rests of malassez
• 50% most common cyst

Clinical:

• associated with non vital teeth
• most common in maxilla

Radiology:
- round radiolucency with radiopaque margin extending from lamina dura of non vital teeth

Treatment:

• Endo Tx
• apicetomy +/- cyst enucleation
• retrograde root filling
• XLA +/- cyst enucleation

Question 6

Residual cysts:

Explain where they are derived from, clinical and radiology signs and treatment options?

Answer 6

Aetiology:

• derived from cell rests of malassez
• peak age >30yrs

Clinical:
- not associated with teeth

Radiology:
- round radiolucency with radiopaque margins not associated with teeth

Treatment:
- enucleation or marsupialisation

Question 7

Dentigerous cysts:

Explain where they are derived from, clinical and radiology signs and treatment options?

Answer 7

Aetiology:

• derived from reduced enamel epithelium
• 2nd most common cyst

Clinical:

• associated with crown of unerupted tooth
• mandibular 3rd molar and maxillary canines most commonly affected

Radiology:
- circumscribed, unilocular, well defined sclerotic margins associated with crown of an unerupted tooth

Treatment:

• Enucleation +/- XLA
• consider coronectomy if risk of nerve damage

Question 8

Eruption cysts:

Explain where they are derived from, clinical and radiology signs and treatment options?

Answer 8

Aetiology:

• derived from reduced enamel epithelium
• most common in children

Clinical:

• painless, soft, fluctuant swelling seen in gingivae overlying erupting tooth
• may be blue or purple
• may be common with deciduous and permanent erupting teeth

Radiology:
- radiolucency lesion at alveolar margin and non bony involvement

Treatment:

• asymptomatic - monitor
• symptomatic - surgical excision

Question 9

Lateral periodontal cyst:

Explain where they are derived from, clinical and radiology signs and treatment options?

Answer 9

Aetiology:

• inconclusive
• peak age 40-70yrs

Clinical:

• may be seen as blue fluctuant swelling associated with gingivae adjacent to vital tooth
• common in mandibular premolars and anterior maxilla regions

Radiology:
- between cervical margin and apex of tooth, round or oval shape, less than 1cm diameter with sclerotic margins

Treatment:
- enucleation or excision

Question 10

Odontogenic keratocyst:

Explain where they are derived from, clinical and radiology signs and treatment options?

Answer 10

Aetiology:

• inconclusive
• lined with stratified squamous keratinised epithelium
• recurs due to daughter cysts, friable lining and site
• 3rd most common cysts

Clinical:

• may have Associated inferior alveolar nerve paraesthesia
• most common on angle of mandible

Radiology:
- may be unilocular/multilocular, defined sclerotic margins but may be diffuse and have scalloped margins.

Treatment:
- enucleation +/- cryotherapy and carnoys solution due to increased recurrence rate

Question 11

What is the pattern of inheritance of Gorlin-Goltz syndrome?

Answer 11

Autosomal dominant condition

Question 12

What is the other name for Gorlin-Goltz syndrome?

Answer 12

Basal cell naevus syndrome

Question 13

What are the characteristic features of Gorlin-goltz syndrome?

Answer 13

Multiple odontogenic keratocysts in young people
Multiple basal cell naevus (BCC)
Mid face hypoplasia 
Frontal bossing - trapezoid skull 
Prognathism 
Falx cerebra calcification. 
Skeletal abnormalities - bifid ribs

Question 14

What radiology feature is observed with nasopalatine cysts?

Answer 14

Radiographic heart shaped radiolucency

Question 15

What is the process of enucleation?

Answer 15

• removal of entire cyst lining and repair of the defect
• incision clear of margin lesions and bone overlying lesion may be removed
• aspiration of lesion contents to allow for dissection and avoid rupture followed by debridement of the area
• sutures will lie over healthy bone once removed
• requires 1 visit as whole lining is removed for histology. Less likely to recur but may require GA/sedation

Question 16

What is the process of marsupialisation?

Answer 16

• involves creation of surgical window in lining of the cyst by removal of overlying mucosa, mucoperiosteal bone to decompress the lumen
• patency of the hole is secured by suture of the cyst lining to mucosa with non resorbable sutures for 10days then removed/replaced
• allows for cyst to decrease due to decreased hydrostatic pressure
• requires multiple visits - minimally invasive, less histology sample and recurrence more common

Question 17

What is an Ochsenbein-Luebke flap?

Answer 17

Modified 3 sided flap for peri radicular surgery

Question 18

What is the process of peri radicular surgery?

Answer 18

Remove 3mm of apex and then remove apical 3mm of obturation using ultrasonic
Cut at right angles to root - perpendicular

Retrograde seal:
- RM ZOE; radiopaque, bacteriostatic. Doesn’t prompt cementogenesis and may resorb.

• MTA: (biocompatible, promotes cementogenesis, good seal and moisture resistant).

Close flap with 4 or 5.0 sutures starting with papillae then relieving incisions.

Question 19

What is the commonest mode of spread of adenoid cystic carcinoma?

Answer 19

Perineural spread