Cysts Of The Jaws COPY

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 cystic lesions like?

Answer 2

Diverse!

Question 3

Describe the typical radiographic presentation of a cyst

Answer 3

Shape
- spherical or egg

Margins
- often well defined
- often corticated

Locularity
- often unilocular
- can be multi or pseudolocular

Multiplicity
- single, bilateral, multiple
- multiple often indicates a syndrome

Effect on surrounding anatomy
- displacement of cortical plates, adjacent teeth, maxillary sinus, IAN canal
- root resorption can occur in chronic cysts

Question 4

Why may a cyst lose its defined corticated margins?

Answer 4

Secondary infection

• typically accompanied by clinical symptoms

Question 5

How are cysts classified?

Answer 5

Structure - epithelium lined vs not

Origin - odontogenic or non-odontogenic

Pathogenesis - developmental vs inflammatory

Question 6

Give all odontogenic developmental cysts

Answer 6

Dentigerous cyst
- eruption cyst

Odontogenic keratocyst

Lateral periodontal cyst

Question 7

Give all odontogenic inflammatory cysts

Answer 7

Radicular cyst
- and residual cyst

Inflammatory collateral cysts
- paradental cyst
- buccal bifurcation cyst

Question 8

Give non-odontogenic, developmental cyst

Answer 8

Nasopalatine duct cyst

Question 9

Give non-odontogenic, other, non-epithelial lined cysts

Answer 9

Solitary bone cyst

Aneurysmal bone cyst

Question 10

What is an odontogenic cyst

Answer 10

Cyst that occurs in tooth-bearing areas
- all lined with epithelium

• most common cause of bony swelling in jaws
• > 90% of all cysts in oral and maxillofacial region

Question 11

What are the most common odontogenic cysts and their incidences?

Answer 11

Radicular cyst and residual cyst - 60% of odontogenic cysts

Dentigerous cyst and eruption cyst - 18%

Odontogenic keratocyst - 12% of cysts in maxfax region

Question 12

What is a radicular cyst? Its incidence?

Answer 12

Inflammatory odontogenic cyst
- always associated with non-vital tooth
- initiated by chronic inflammation at apex of tooth due to pulpal necrosis

60% maxilla
40% mandible
40s and 50s age

Question 13

Sources of epithelium in cysts?

Answer 13

Hertwigs root sheath

Rests of serres
- remnants of dental lamina

Reduced enamel epithelium
- remnants of enamel organ

Question 14

Radicular cyst vs periapical granuloma?

Answer 14

Radiolucency >15mm
- 2/3 of cases with be cyst

Periapical granuloma develops into radicular cyst

Question 15

Presentation of radicular cyst?

Answer 15

Often asymptomatic
- may become infected and become symptomatic

Slow-growing with limited expansion

Question 16

Radiographic presentation of radicular cyst?

Answer 16

Well-defined, corticated margin, round/oval
- continuous with Lamina dura of non-vital tooth

Long standing lesions may:
- displace surrounding anatomy
- cause external root resorption =

Question 17

Histology of a radicular cyst

Answer 17

Epithelial lining that is often incomplete
- connective tissue capsule
- inflammation inside the capsule

Question 18

How does periapical granuloma form a radicular cyst?

Answer 18

Epithelial rests of malassez (hertwigs root sheath remnants) proliferates in the granuloma

Question 19

What is a residual cyst?

Answer 19

Variant of radicular cyst
- radicular cyst persists after removal of tooth, or after successful RCT

Question 20

What is a lateral radicular cyst?

Answer 20

Radicular cyst associated with accessory canal
- located at side of tooth and not apex

Question 21

What is an inflammatory collateral cyst?

Answer 21

Inflammatory odontogenic cyst
- associated with vital tooth
- pouch lined with non-keratinised epithelium

Collective term used for

Paradental cyst - distal aspect of partially erupted mandibular third molar

Buccal bifurcation cyst - buccal aspect of mandibular first molar

Question 22

What is a Dentigerous cyst?

Answer 22

Developmental odontogenic cyst
- associated with crown of unerupted and usually impacted tooth
- cystic change of dental follicle

Question 23

Radiographic presentation of Dentigerous cyst?

Answer 23

Corticated margins attached to CEJ of tooth
- larger ones may begin to envelope root of tooth

• may displace involved tooth
• initially symmetrical
• variable displacement of cortical bone

Question 24

Histology of Dentigerous cyst?

Answer 24

Thin, non-keratinised stratified squamous epithelium
- may resemble radicular cyst if inflamed

Question 25

When may an enlarged follicle be a Dentigerous cyst?

Answer 25

Follicle space 5mm or more - crown surface to edge of follicle Should normally be 2-3mm Assume cyst if >10mm

Question 26

What is an eruption cyst?

Answer 26

Variant of Dentigerous cyst - contained within soft tissue rather than bone - associated with an erupting tooth - more commonly incisors and almost exclusive to children

Question 27

What is an odontogenic keratocyst? Its incidence?

Answer 27

Developmental odontogenic cyst with no specific relationship to teeth 20s-30s Mandible 3:1 maxilla Posterior > anterior

Question 28

Radiographic appearance of odontogenic keratocyst ?

Answer 28

Scalloped margins 25% multilocuar Often cause displacement of adjacent teeth Often significant mesial-distal expansion with little bucolic-lingual expansion

Question 29

Pre-operative diagnostic tests for odontogenic keratocyst

Answer 29

Cyst aspirate

Question 30

Histology of OKC?

Answer 30

Parakeratosis Loss of keratin if inflamed Thin friable lining Daughter cysts

Question 31

What is basal cell naevus syndrome

Answer 31

Multiple odontogenic keratocyst Multiple basal cell carcinomas Calcification of intracranial dura mater Cysts histologically identical to non-syndromes form except these occur younger at around 15

Question 32

What is a nasopalatine duct cyst? Incidence?

Answer 32

Developmental, non-odontogenic cyst - arising from epithelial remnants in nasopalatine duct 40s-60s M>F

Question 33

What is a nasopalatine duct cyst?

Answer 33

Developmental, non-odontogenic cyst arising from epithelium of nasopalatine duct 40s-60s M>F

Question 34

Clinical presentation of nasopaltine cyst?

Answer 34

Often asymptomatic Pt may report salty discharge Larger cysts may displace teeth or cause palatal swelling Always involve mid line but not always symmetrical

Question 35

Radiographic presentation of nasopalatine cyst?

Answer 35

Corticated radiolucency between / over roots of central incisors Often unilocular

Question 36

How monitor incisive fossa vs nasopalatine cyst?

Answer 36

<6mm assume incisive fossa 6-10mm consider monitoring >10mm assume cyst

Question 37

What is a solitary bone cyst? Incidence?

Answer 37

Non-odontogenic cyst without an epithelial lining 20s M>F Mandible >> maxilla

Question 38

Clinical presentations of solitary bone cyst?

Answer 38

Usually asymptomatic - rarely pain or swelling

Question 39

Radiographic presentation of solitary bone cyst?

Answer 39

Premolar / molar region of mandible Variable definition and cortication Scalloped / psuedolocular appearance May project up between roots of adjacent teeth

Question 40

What is a stafne cavity?

Answer 40

Not a cyst, but a depression in bone that is filled with salivary or fatty tissue - always in mandible - posterior body or angle - often inferior to IAN - well defined and corticated

Question 41

Why take incisional biopsy of cyst?

Answer 41

Obtain sample for histological analysis - be combined with marsuipialisation sometimes

Question 42

Options for tx of cyst?

Answer 42

Enucleation - all of cystic lesion removed Marsupialisation - creation of surgical window in wall of cyst so contents can be removed - encourages cyst to decrease in size

Question 43

Advantages enucleation?

Answer 43

- Whole lining can be pathologically examined - primary closure - little aftercare - less % recurrence

Question 44

Contraindications / disadvantages enucleaiton

Answer 44

Risk of mandibular fracture Would rather Preserve tooth if dentigerous Old age / ill health Recurrence higher % Damage to adjacent structures

Question 45

Indications for marsupialisation?

Answer 45

If enucleation would damage surrounding tissues such as IAN When access is difficult Dentigerous cyst may erupt after Elderly / immunocompromised Very large cysts which may cause mandibular fracture

Question 46

Contraindications / disadvantages to marsupialisation?

Answer 46

Cyst reformation Complete lining not available for histology Difficult to clean with lots of aftercare Long time to fill in

Question 47

How may a marsupialised cyst be kept open?

Answer 47

Obturator made from thermoplastic retainer