CYST OF THE JAWS

PRESENTED BY: MOHD. AMIR BDS FINAL YEAR ROLL NO.34

CONTENT DEFINITION CLASSIFICATIONS PATHOGENESIS SIGNS OF CYST RADIOGRAPHS FOR CYST DIAGNOSIS BASED ON TYPE OF

ASPIARATION OPERATIVE PROCEDURES COMPLICATIONS OF CYST

MANAGEMANT

CYST OF THE JAWS

A cyst is defined as an abnormal cavity in hard or soft tissue which contains fluid, semifluid or gas and is often encapsulated and lined by epithelium (Killey and Kay 1966).

In 1974, Kramer defined cysts as a pathological cavity having fluid, semi-fluid or gaseous contents that are not created by the accumulation of pus, frequently but not always, is lined by epithelium.

Classifications Various classifications have been given to describe

these lesions: 1. Robinson (1945) 2. WHO classification (1971) 3. Shear's classification (1983)

WHO Classification Epithelial cysts A. Developmental cysts 1. Odontogenic a) Primordial cyst (keratocyst) b) Gingival cyst c) Eruption cyst

d) Dentigerous cyst (folificular) 2.Non-odontogenic a) Nasopalatine (incisive canal) b) Globulomaxillary c) Nasolabial Inflammatory cysts Radicular cysts

Robinson ‘s Classification

Developmental From odontogenic tissue 1. Periodontal cysts a) Radicular cysts b) Lateral cyst c) Residual cyst 2. Dentigerous cyst 3. Primordial cyst From non-odontogenic tissues 1. Median cyst 2. Incisive canal cyst 3. Globulomaxillary cyst

Shear’s classification 1.Cysts of the jaws 2.Cysts associated With maxillary

antrum a)Benign mucosal cyst of maxillary antrum. b)Surgical ciliated cyst of the maxilla.

3. Cysts of soft tissues of mouth, face and neck

a)Dermoid and epidermoid cyst b) Branchial cyst c)Thyroglossal duct cyst e)Cystic hygroma f)Cysts of salivary glands g)Parasitic/hydatid cysts

Cysts of the jaws Epithelial a)odontogenic i)development --> Primordial -> Gingival cysts of infants -> Gingival cysts of adults -> Lateral periodontal -> Dentigerous -> Eruption cysts ->.Calcifying odontogenic cyst

ii)inflammatory-->Radical--> Residual-->Paradental b)non-odontogenic--> Nasopalatine--> Median palatine, alveolar, mandibular--> Globulomaxillary--> Nasolabial Non-epithelial--> Simple bone cysts-->Traumatic bone cyst --> Solitary bone cyst--> Hemorrhagic bone cyst--> Aneurysmal bone cyst

PATHOGENESIS Steps in Cyst Formation The formation of a cyst takes place in

generally three stages: 1. Initiation 2. Cyst formation 3. Enlargement or expansion of cyst cavity Cyst Initiation The factors initiating the formation of the

cyst may be different depending on the type of cyst that is formed.

A chronic low grade infection due to the bacterial invasion of the pulp may cause activation of the usually dormant cell rests of Mallessez. This causes initiation of the cyst process.

Cyst Formation It is proposed that during this stage, the cyst

cavity gets lined by stratified squamous epithelium.The blood supply is rich at the periphery and the cells present in the centre lack nutrition. As a result, these cells tend to desquamate into the centre of the mass. This produces a fluid with increased osmolarity in the centre surrounded by an epithelial lining

Cyst Enlargement The basic mechanism for enlargement is the same for

most cysts. Various factors involved are: 1. Production of raised internal hydrostatic

pressure The most commonly accepted mechanism is that the

desquamated epithelial cells undergo autolysis and release a large number of low molecular weight molecules. This increases the osmolarity of the fluid within the cyst.

2. Attraction of fluid into the cystic cavity This increased osmolarity of the fluid draws fluid from the

surrounding tissue spaces into the cystic cavity due to the osmotic differences. It is also believed that acute inflammation makes the capillaries in the region highly permeable

This results in exudation of protein rich fluids into the cystic cavity. This is considered another mechanism for accumulation of fluids into the cyst cavity.

3. Retention of fluid within the cystic cavity It is believed that the cyst lining acts as a semi-

permeable membrane allowing fluid to enter the cavity .but preventing it from going out.

Toller's experiments have shown that the osmotic imbalance resulted in the inability of the large molecules in the fluid to escape because of lack of access to the lymphatic system.

4. Epithelial growth Mural growth or the growth of the cells of the cystic

lining itself helps in expansion of the size of the cyst.

5. Resorption of surrounding hone A positive internal pressure transmitted to the adjacent

bone causes resorption and enables enlargement, Osteoclastic factors such as PGE.

Further enlargement of the cystic lesion within the bone produces microcracks on the further thinned out cortical plates. When the cortical plates are palpated, it produces a grating noise described as 'egg shell crackling'.

In a later stage, thinned out alveolar bone completely resorbs and the cyst lining lies just beneath the oral mucosa. Fluctuation may be elicited at this stage.

Later perforation of the cyst lining and oral mucosa may cause drainage of cyst contents into the oral cavity producing a salty taste2, PGE3 play a role in bone resorption

Signs of cyst:

Examination findings 1. Bone expansion 2. Fluctuant swelling under oral mucosa 3. Non vital tooth (if radicular cyst)- 4. Missing tooth in normal series 5. Sinus formation with discharge 6. Large cyst distortion of adjacent

structures 7. Hollow sound on percussion

- Radiographs for cyst

1. IOPA for small periapical cyst to see tooth involved 2. Occlusal view to check lingual cortical expansion/perforation 3. PNS view (occipitomental) to show

relation to maxillary antrum and nasal cavity

4. Lateral oblique (mandible) to check proximity to lower border

5. PA view to check expansion of ramus of mandible

6. OPG recommended in most cases; entire extent, size etc. can be assessed

Dentigerous cyst-unilocular ,well defined radiolucency with sclerotic border around the crown of an unerupted tooth.

Three radiographic type-circumcoronal,circumferential and lateral.

Odontogenic keratocyst-multilocular radiolucency and give “soap bubble appearance”.

Radicular cyst-solitary well circumscribed radiolucency attached to the apex of the non-vital tooth.

Diagnosis based on type of aspirate

1. Clear, pale, straw coloured fluid with cholesterol crystals. Dentigerous cyst

2. Creamy white, thick aspirate Odontogenic keratocyst

3. Yellowish, foul smelling fluid (pus) Infected cyst

4. Blood on aspiration Needle in a blood vessel Vascular lesion ABC

5. Air on aspiration Maxillary antrum Traumatic bone cyst

6. Negative aspiration Solid tumor

Operative Procedures

Basically two types of procedures for treatment:

1. Enucleation 2. Marsupialisation

Marsupialisation or Partsch I Operation

(cys-totomy) • In 1892 Partsch described a type of

decompression procedure for the treatment of cysts.

• In this procedure, a window or a fenestra-tion is made in the bone and the cystic con tents are evacuated. The cyst lining is left behind.

• Once the cyst contents are evacuated, the intracystic pressure reduces. The hollow cavity is then packed till it gets obliterated by bone slowly over a period of time.

• The cystic lining then becomes continuous with the normal oral mucosa

Advantages of Marsupialisation

1. Once the liquid contents of the cyst are re leased, there is an inherent tendency for the cyst lining to contract probably due to myofibrils in the walls. This stimulates endosteal bone formation.

2. As the cyst lining shrinks, there is a marginal ingrowth of normal mucoperiosteum which replaced the capsule with its resorptive potential.The ingrowing mucoperiosteum may provide it with additional bone re generation factors.

3. This is a more conservative method. 4. Not much surgical skill is required. 5. There is no risk of oroantral or oronasal fis tula. 6. No damage to the adjacent vital structures. 7. No risk to adjacent vital teeth.

Disadvantages of Marsupialisation \. Entire pathological tissue is left behind. 2. High chances of recurrence of the cyst. 3. As the bony cavity is large, healing and fill ing

up with normal bone takes a long time. 4. Use of cyst plug is required with repeated

cleansing. 5. Time consuming and repeated appointments

for the patient. Indications for Marsupialisation 1. Extremely large cyst 2. Risk of cyst opening into maxillary sinus or

nose due to surgical removal of complete lesion

Enucleation (Partsch ll/cystectomy)

Enucleation is the surgical removal of the entire cystic lining in toto.

By definition, it means shelling out of the entire cystic lining without rupture.

This surgical procedure leaves behind a hollow cavity in bone covered by oral mucoperiosteum. This gets filled up with blood clot which even tually organizes to form healthy bone.

Advantages of Enucleation

1. Entire pathological tissue is removed from the lesion.

2. Tissue available for hi stopathological exami nation.

3. Chances of recurrence are less. 4. Healing time is faster and less

appointments for the patient 5. Enucleation with primary closure

eliminates the need for repeated appointments for pack ing medicated gauze, irrigation, fabrication of plug etc.

Disadvantages of Enucleation

1. Relatively radical procedure 2. Chances of devitalising the adjacent

teeth 3. Chances of fracture of the jaw 4. Risk of creation of oroantral/oronasal

communication. Indications for Enucleation Enucleation is the treatment of choice for re

moval of cysts of the jaws and should be employed with any cyst of the jaw that can be safely removed without unduly sacrificing the under lying structures.

Enucleation

Small cysts can be removed under local an esthesia whereas large cysts close to vital structures and blood vessels should be taken out under general anesthesia.

After achieving adequate anesthesia, a mucoperiosteal incision is made such that the incision rests on sound bone.

Mucoperiosteal flap is reflected taking care not to perforate the cystic lining.

If the bone is perforated by the cyst, the lining will be adherent to the periosteum and will be difficult to reflect it.

Cystic lining is exposed and now carefully teased away from bone. Its easy to separate the cystic lining from bone because there is a layer of fibrous tissue between the two.

After the cyst is removed completely the cavity is irrigated throughly,hemostasis ensured,sharp bone margin are filed and flap replaced and sutured.

Enucleation open packing:- Gauze impregnated with bismuth iodoform

parraffin paste (BIPP) or whitehead varnish. Enucleation with bone grafting:-

• Bone grafting with autogenous cancellous bone grafts can be done in case of large bony defects.

• The bone graft obliterates the cavity and stimulates osteogenesis.

• There is, however, a risk of wound break down and infection of the bone graft which may lead to failure.

Composition of carnoy's solution

1. Glacial acetic acid 2. Chloroform 3. Absolute alcohol 4. Ferric chloride It is indicated mainly in cases of

odontogenic keratocyst. Afterenucleation, to remove any re maining lining of the cyst chemical cauterising agent Carnoy's solution is applied along the walls of the cystic cavity. It is left for about 5-7 minutes and then irrigated thoroughly with saline.

Complications of cyst management

1. Injury to inferior alveolar nerve 2. Injury to adjacent teeth 3. Fracture of jaw 4. Oro antral fistula communication 5. Hematoma formation 6. infection 7. Dead space 8. Incomplete removal 9. Recurrence 10. Malignant transformation