Cysts

Question 1

What is a cyst ?

Answer 1

A pathological cavity having fluid, semi-fluid or gaseous contents and which is not created by accumulation of pus.

Question 2

What are some symptoms of cysts ?

Answer 2

Mobile teeth. Swelling. Discolouration. Pain or tenderness of teeth. Numbness. Loss of tooth vitality. Egg shell crackling. Failure of eruption.

Question 3

Name 3 developmental odontogenic cysts.

Answer 3

Dentigerous cyst (or eruption cyst).
Odontogenic keratocyst.
Lateral periodontal cyst.

Question 4

Name a development non-odontogenic cyst.

Answer 4

Nasopalatine duct cyst.

Question 5

Name two other non-odontogenic cysts.

Answer 5

Aneurysmal bone cyst.
Solitary bone cyst.

Question 6

What are the signs of a radicular cyst ?

Answer 6

Always associated with non-vital tooth.
Asymptomatic (if uninfected).
Slow growing with little expansion.

Question 7

How to differentiate between radicular cyst and a PA granuloma ?

Answer 7

Cysts >15mm in size.
Granulomas <15mm in size.
Cannot differentiate otherwise radiographically.

Question 8

When are radicular cysts more likely to occur ?

Answer 8

50-60 years old.

Question 9

Describe the radiographic characteristics of a radicular cyst.

Answer 9

Well defined, round/oval radiolucency.
Corticated margin continuous with lamina dura of non-vital tooth.
Can displace adjacent structures.
Can cause external RR or contain dystrophic calcification.

Question 10

Describe a radicular cyst histologically.

Answer 10

Incomplete hyperplastic epithelial lining.
Connective tissue capsule.
Inflammatory cells within.
Can have ulceration.

Question 11

Define residual cyst - variant of radicular cyst.

Answer 11

When radicular cyst persists after loss of tooth or after tooth is successfully RCT’d.

Question 12

Define lateral radicular cyst - variant of radicular cyst.

Answer 12

Associated with accessory canal.
Located at side of tooth instead of apex.

Question 13

Define paradental cyst.

Answer 13

Typically occurs at distal aspect of partially-erupted mandibular third molar.

Question 14

Describe a dentigerous cyst.

Answer 14

Developmental odontogenic cyst associated with crown of unerupted (and usually impacted) tooth.
Where cystic change occurs in dental follicle.

Question 15

What teeth are dentigerous cysts most likely to affect ?

Answer 15

Mandibular third molars.
Maxillary canines.

Question 16

When are dentigerous cysts most common ?

Answer 16

2-4th decades.

Question 17

Describe the radiographic appearance of a dentigerous cyst.

Answer 17

Associated with unerupted tooth.
Corticated margins attached to ECJ.
Tends to expand symmetrically.
Variable bony expansion.
May displace tooth involved or anatomy.
Unilocular.

Question 18

Describe the histological appearance of a dentigerous cyst.

Answer 18

Thin non-keratinised stratified squamous epithelium.
Variable inflammatory cells.
Hyaline/Rushton bodies.
Mucous metaplasia.
Cholesterol clefts.

Question 19

At what measurement does a enlarged follicle become a dentigerous cyst ?

Answer 19

Widening >5mm be suspicious.
>10mm assume cyst.

Question 20

What are the risks of leaving a dentigerous cyst untreated ?

Answer 20

Weakened bone - risk of mandibular fracture.
Compression of nerve - numbness of lip;.

Question 21

What is the most common non-odontogenic cyst ?

Answer 21

Nasopalatine duct cyst.

Question 22

What radiographs would you require to investigate a nasopalatine duct cyst ?

Answer 22

PA +/- anterior maxillary occlusal.
CBCT if surgical planning.

Question 23

What diameter would you expect the incisive fossa to be ?

Answer 23

<6mm

6-10mm be suspicious and monitor, >10mm assume cyst.

Question 24

Describe the radiographic appearance of a nasopalatine duct cyst.

Answer 24

Unilocular.
Well defined.
Corticated margins over roots of centrals.
Heart shaped due to superimposition of anterior nasal spine.

Question 25

Describe the clinical presentation of nasopalatine duct cyst.

Answer 25

Asymptomatic.
Salty discharge.
Can displace teeth.
Can cause swelling on palate.
Always involve midline.
Not always symmetrical.

Question 26

Describe the histological features of a nasopalatine duct cyst.

Answer 26

Non-keratinised stratified squamous epithelium OR modified respiratory epithelium.

Question 27

Are solitary bone cysts more common in mandible or maxilla ?

Answer 27

Mandible.

Question 28

Do solitary bone cysts require treatment/follow up ?

Answer 28

No treatment required usually.
Review and monitor every 3 months.

Question 29

What are the radiographic characteristics of solitary bone cysts ?

Answer 29

Premolar/molar regions.
Non-tooth bearing areas.
Variable cortications.
Scalloped margins with pseudolocular appearance.
Projection between teeth.

Question 30

What are the three histological samples you can take to assess and definitively diagnose a cyst ?

Answer 30

Aspiration biopsy.
Incisional biopsy.
Excisional biopsy.

Question 31

What are the two surgical options for cysts ?

Answer 31

Enucleation.
Marsupulisation.

Question 32

Describe marsupulisation.

Answer 32

Creation of surgical window in wall of cyst.
Remove contents of cyst.
Suture cyst wall to surrounding epithelium.
Leave open in oral cavity.

Question 33

What is the aim of marsupulisation ?

Answer 33

Encourage cyst to decrease in size.
Sometimes prior to enucleation.

Question 34

What are the indications for marsupulisation ?

Answer 34

Where enucleation would damage IAN.
Difficult access.
Can allow eruption of teeth.
Elderly/medically compromised.
Large cysts which would risk jaw fracture.
Combined with enucleation.

Question 35

What are the advantages of marsupulisation ?

Answer 35

Easy to perform.
Can spare vital structures.

Question 36

What is the disadvantages of marsupulisation ?

Answer 36

Opening can close and cause reformation of cyst.
Complete lining not available for histology.
Difficult to keep clean.
Long time for bone to fill void.