Cysts of the Jaw

Question 1

definition of a cyst

Answer 1

pathological cavity with fluid, semi-fluid or gaseous contents which is not created by the accumulation of pus

Question 2

signs and symptoms of a cyst (4)

Answer 2

• mobility of teeth
• bony swelling
• numbness (if pressing on a nerve)
• loss of vitality of teeth
• previously hard structure now feels like egg shell cracking when pressed , due to thinned bone

Question 3

radiographic features of cysts
- shape
- margins
- locularity
- multiplicity

Answer 3

• usually spherical or egg shaped
• well defined corticated margins
• majority unilocular
• almost always singular

Question 4

by what method do majority of cysts grow

Answer 4

hydrostatic pressure
(pressure exerted by fluid in a confined space)

Question 5

what impact will infection have on a cyst

Answer 5

radiographically - loss of corticated margins and loss of definition
clinically - painful, fever, pus

Question 6

what are the 3 ways cysts of the jaw can be classified

Answer 6

structure - epithelium lined or not
origin - odontogenic or non odontogenic
pathogenesis - developmental or inflammatory

Question 7

what is the most common odontogenic cyst

Answer 7

radicular cyst
(residual)

Question 8

name 2 developmental odontogenic cysts

Answer 8

dentigerous cyst
odontogenic keratocyst

(lateral periodontal cyst)

Question 9

name an inflammatory odontogenic cyst

Answer 9

radicular cyst

(inflammatory collateral cysts)

Question 10

name a developmental non odontogenic cyst

Answer 10

naso-palatine duct cyst

Question 11

name 2 features that are always present in odontogenic cysts

Answer 11

• always lined with epithelium
• always above the IA canal

Question 12

what are the 3 odontogenic sources of epithelium

Answer 12

• rests of mallasez (remnants of HERS)
• rests of Serres (remnants of dental lamina)
• reduced enamel epithelium (remnants of enamel organ)

Question 13

what are radicular cysts always associated with

Answer 13

always associated with a non vital tooth - initiated by chronic inflammation at apex of tooth due to pulp necrosis

Question 14

what age group do radicular cysts most commonly affect

Answer 14

40s/50s

Question 15

what may a radicular cyst be confused with radiographically if small

Answer 15

periapical granuloma

Question 16

radiographic appearance of a radicular cyst

Answer 16

• associated with a non vital tooth
• corticated cyst margins will be continuous with lamina dura of non-vital tooth
• large lesions may displace other structures

Question 17

how does a radicular cyst form from a granuloma

Answer 17

epithelial rests of malassez proliferate in periapical granuloma
continued growth via cytokines and central necrosis sees transition to cyst

Question 18

residual cyst

Answer 18

when a radicular cyst persists after loss of a tooth or after successful RCT

extraction of non vital tooth will not cure radicular cyst, cyst requires removal

Question 19

dentigerous cyst

Answer 19

developmental cyst from reduced enamel epithelium associated with the crown of an unerupted tooth

Question 20

radiographic appearance of a dentigerous cyst

Answer 20

associated with crown of an unerupted tooth - corticated margins will meet crown at ECJ
crown will be within cyst, tooth may be displaced

Question 21

dentigerous cyst vs enlarged follicle

Answer 21

normal follicular space 2-3mm
consider cyst if follicular cyst >5mm, presume cyst if >10mm

(always consider cyst if radiolucency asymmetrical)