Odontogenic cyst

-

1. Cyst of orofacial
region
Asok kumar RS OMFS

2. Definition
A cyst is an abnormal cavity in hard or soft tissues which contains fluid, semi-fluid,
or gas and is often encapsulated and lined by epithelium.
Killey & Kay (1966)
A cyst is a pathologic cavity having fluid, semi- fluid or gaseous contents that are
not created by the accumulation of pus; frequently, but not always lined by
epithelium.
Kramer (1974)
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3. Classification
TRUE CYST: Cyst which is lined by epithelium
e.g. Dentigerous cyst, Radicular cyst etc.

PSEUDOCYST: Cyst which is not lined by epithelium
e.g. Solitary bone cyst, Aneurysmal bone cyst, Traumatic bone cyst
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4. Classification (Shear-1983)
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5. ODONTOGENIC



NON ODONTOGENIC
Classification
DEVELOPMENTAL
I.Primordial cyst
II.Dentigerous cyst
III.Lateral periodontal cyst
IV.Calcifying odontogenic (Gorlin) cyst
INFLAMMATORY
I.Radicular cyst
II.Residual cyst
FISSURAL
I.Median palatine cyst
II.Median mandibular cyst
III.Globulomaxillary cyst
INCISIVE CANAL
I.Nasopalatine cyst
II.Median anterior maxillary cyst


According to WHO (1992) : Epithelial cysts (INTRAOSSEOUS)

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6. NON EPITHELIAL (PSEUDOCYST)
I.Stafne bone cyst
II.Solitary bone cyst
III.Aneurysmal bone cyst
CYST OF MAXILLARY ANTRUM
I.Surgical ciliated cyst of maxilla
II.Benign mucosal cyst of maxillary antrum

Classification
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7. SOFT TISSUE CYST:
ODONTOGENIC CYST
GINGIVAL CYSTS
I.Adult
II. Newborn
 ERUPTION CYST
NON ODONTOGENIC
I.Anterior median lingual cyst
II.Nasolabial cyst
RETENTION CYST
SALIVARY GLAND CYST
I.Mucocele
II.Ranula

Classification
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8. DEVELOPMETAL CYST
I.Dermoid and epidermoid cysts
II.Lymphoepithelial cyst
III.Thyroglossal duct cyst
IV.Cystic hygroma
PARASITIC CYST
I.Hydatid cyst
II.Cysticercosis
HETEROPIC CYST
Classification
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9. Pathogenesis of cyst formation
Three phases
a)Cyst initiation.
b)Cyst formation.
c)Cyst enlargement.
Asok kumar RS OMFS

10. Cyst initiation and formation

Initiation of cyst formation is mostly from odontogenic epithelium

CELL RESTS OF MALASSEZ :
Remanants of Hertwig epithelial root sheath in the Periodontal ligament after the root formation is completed.

 REDUCED ENAMEL EPITHELIUM :
Residual epithelial cells surrounds the crown of the tooth after enamel formation is complete.

 CELL RESTS OF SERRES (DENTAL LAMINA) :
Islands of epithelial cells that originate from the oral epithelium remain in the tissue after inducing tooth
development

BASAL LAYER OF ORAL EPITHELIUM

TOOTH GERM

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11. Odontogenic and non odontogenic cyst deriatives
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12. Cyst enlargement
Once cyst formation has been initiated, it continues to grow and
enlarge.
Theories of cyst enlargement (MALCOLM HARRIS 1975):
I.Mural growth theory
II. Osmotic theory
III.Bone resorption theory
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13. Mural growth theory
I.PERIPHERAL CELL DIVISION
Active division of epithelial cells lining result in cyst enlargement at
the peripheries
 Rapid resorption of surrounding bone to accommodate the
enlarging cyst.
II. ACCUMULATION OF CELLULAR CONTENTS
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14. Osmotic theory
Accumulation of fluid and inadequate lymphatic drainage within the cyst wall
causes the expansion of the cyst
Bone resorption theory
Cystic capsule contains very potent bone resorbing factors like Prostaglandin PGE2,
PGE3 and leukotrines.
Increased internal pressure also causes bone resorption and enlargement of cyst cavity.
The expansion causes egg shell crackling on palpation due to microcracks on the thinned
out cortical bone.
Complete resorption and perforation of cortical bone occurs of further expansion.
Asok kumar RS OMFS

15. Cyst enlargement mechanisms
I.Increase in the volume of contents
II.Hyperosmosis
III.Resorption of surrounding bone when the cyst develops within bone
IV.Increase in cyst surface area.
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16. Increase in volume of contents

Due to
I.Accumulation of mucous as in mucus secreting cyst
II.PGE2
III.Lymphokines,
IV.Osteoclast activating factor
V.Interleukin 1 fibroblast Prostaglandin

VI.Enlargement determined by: Continuous stimulation of epithelial proliferation

stimulate release
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17. OSMOTIC THEORY OF ENLARGEMENT MAIN ,HARRIS AND TOLLER
(1975)

Epithelial cell break down products

Hyperosmolar cyst fluid

Draws in fluid from surroundng tissues

Hydrostatic pressure

Oncotic pressure

Cyst permeability

Cyst enlargement Asok kumar RS OMFS

18. INCREASE IN CYST SURFACE AREA
Mural growth : Epithelial proliferation

Area of sac
Peripheral cell division/ accumulation of cellular contents
Multicentric gowth pattern
Collagenase activity
Unremitting growth of high mitotic epithelial linings
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19. Bone resorption
Cyst gets enlarged within bony cavity , as epithelial cells divide
Release PGE2 ,leukotriene
Osteoclast function


Size of cyst determined by - Quantity of prostaglandin released and
bone resorbing factors.
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20. Cyst regression
Extraction of tooth /Reduction of intra cystic pressure


Involution of cyst

Regression of connective tissue

Cavity gets filled by bone or scar tissue.
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21. Clinical features
I.Pain and swelling in involved region
II.Salty /Unpleasant taste in mouth
III.Bone expansion.
IV.Fluctuant swelling under oral mucosa
V.Loss of tooth vitality
VI.Missing tooth in normal series
VII.Sinus formation with discharge
VIII.Pathological fractures
IX.Large cyst distortion of adjacent structures
X.Hollow sound on percussion
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22. Clinical features
xi.Ill fitting dentures
xii.Displacement of teeth
xiii.Discoloration of teeth
xiv.Neurosensory disturbances
Initially lateral bone expansion turns to thinning of cortex and egg shell crackling
evident in palpation
Later the outer shell disappears and the cyst lining is present beneath oral mucosa


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23. Cyst location

•Gingival cyst
•Epithelial cyst
•Lateral periodontal cyst
•Residual cyst
•Periapical cyst
•Dentigerous cyst
•Odontogenic keratocyst
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24. Radiographs
SMALL SIZED CYST:
I. IOPA -small periapical cyst
II. Occlusal radiograph –cortical expansion/perforation
LARGE SIZED CYST:
I. OPG – entire extent, size
II. WATERS VIEW -relation to maxillary antrum and nasal cavity
III. LATERAL OBLIQUE VIEW -to check proximity to lower border of mandible
IV. PA VIEW - expansion of ramus of mandible
V. CT
VI. CBCT
VII.ULTRASOUND
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25. Aspiration
•Indicates nature of the cystic lesion
•Done under local anaesthesia with the help of a wide bore
needle.
•The aspirated fluid is studied to find out the nature of the
lesion.
•Aspiration of air indicates that the needle has entered the
antrum.
•No contents on aspiration, it indicates a tumour
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26. Asok kumar RS OMFS

27. Biopsy
Biopsy is a method of removal of tissues from the living organism to determine the presence or extent of
the disease.
to remove a portion of the lesional tissue in question along with a sample of normal adjacent tissue for
comparison.
Gold standard for determining the type of cysts and to differentiate them from neoplasms
INCISIONAL BIOPSY
Excision of a precise portion of the oral lesion for microscopic examination.
INDICATION:
Large, diffuse lesions above the size of 2 cm
Lesions with malignant potential. Asok kumar RS OMFS

28. Excisional biopsy
Entire lesion is removed for examination and diagnosis.
Diagnostic, as well as curative
ADVANTAGES
Allows histopathologic examination of an entire lesion.
Another advantage of an excisional biopsy is the amount of tissue that can be removed from one biopsy site,
ensuring adequate samples for various studies, such as culture, histopathology, immuno-fluorescence and electron
microscopy.
DISADVANTAGES
 If the tumour is highly infiltrative, the margin of excision cannot beprecisley elicited
 Furthermore, cancerous cells actively multiply at the tumour margins, debulking of the mass may result in residual
cancerous cells left behind.
Excision needs greater precision
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29. Management

OBJECTIVES:
Complete elimination of the pathologic lesion
Cause minimal destruction and damage to the surrounding soft and hard tissues
Restore normal function
The tooth germ, the unerupted or partially erupted teeth should be conserved as far as possible
and should be allowed to erupt.
Preservation of the adjacent vital structures like neurovascular bundle, nasal or antral
lining mucosa, etc

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30. Treatment modalities
MARSUPIALIZATION (DECOMPRESSION)
I. Partsch I
II.Partsch II (combined marsupialization and enucleation)
III.Marsupialization by opening into nose or antrum.
 ENUCLEATION
I. Enucleation with open packing
II.Enucleation with primary closure
III.Enucleation and primary closure with reconstruction/bone grafting.
IV.Enucleation with chemical cauterization
ENBLOCK EXCISION
SEGMENTAL RESECTION
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31. Marsupialization
First described by Partsch in 1892
Creation of surgical window is made in the cyst wall and lining is sutured to oral mucosa and
cyst is decompressed
Cavity is then regularly packed open with iodoform gauze coated with tincture benzoin till
healing
Decreases intracystic pressure and promotes shrinkage of the cyst and bone fill Asok kumar RS OMFS

32. Indications
Young children -preserves the tooth germ associated with the cyst and helps in normal
eruption of the teeth.
In case of large cysts where enucleation would result in pathologic fracture
Cyst is in close proximity with vital structures in order to prevent the formation of oronasal or
oroantral fistula or injury to adjacent neurovascular structures
To maintain the vitality of these teeth.
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33. Surgical procedure
INCISIONS:
A circular, oval or elliptic incision of 1cm or larger in size leaving a margin of 0.
5–1 cm from the gingival margins of the teeth or alveola crest in the edentulous
patient.
REMOVAL OF BONE:
Bone removal is done either by the use of a rotary bur or rongeurs depending
upon its thickness. Removal of the bone should be done to the maximum diameter
of the cyst whenever possible.
SUTURING:
The remaining cystic lining is sutured with the edge of the oral mucosa by
continuous sutures or interrupted sutures
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34. PACKING:
Packed with ribbon gauze impregnated with an antibiotic ointment, Whitehead’s
varnish, tincture of benzoin or bismuth iodoform paraffin paste (BIPP).
Prevent contamination of the cavity with food debris and also provide coverage to wound
margin.
Packs are secured by sutures and left inside for 7–14 days.
MECHANISM:
Release of intra cystic fluid
Release of intracystic pressure
Gradual obliteration of cyst
Cystic lining diminshes and replace with new bone
Surgical procedure
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35. Marsupialization of maxillary cyst
Marsupialization of mandibular cyst
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36. USE OF PLUG:
A plug may be designed to prevent the contamination of the cystic cavity and preserve the
patency of the cyst orifice. The plug should be stable, retentive and of a safe design so that it
cannot be inhaled or swallowed.
FEATURES OF A PLUG
Should be retentive and maintain the patency of the cavity.
Should not irritate the mucosa.
Should never reach till depth of the cavity, as this would interfere with the bone regeneration
and filling process.
The plug can be attached to the dentures in case of edentulous patients.
Should be vented to avoid pressure build up within the cavity.
Should be designed such that it is not swallowed or inhaled by the patient
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37. Advantages

Advantages
Simple procedure to perform
Preservation of vital structures
 Allows eruption of teeth
 Prevents oronasal, oroantral fistulae
Prevents pathological fractures
 Reduces operating time
 Reduces blood loss
 Helps shrinkage of cystic lining
 Allows for endosteal bone formation to take place
 Alveolar ridge is preserved.

Disadvantages
 Pathologic tissue is left in situ
 Histologic examination of the entire cystic lining is not done
 Prolonged healing time
 Inconvenience to the patient
 Prolonged follow-up visits
 Periodic irrigation of cavity
 Regular adjustments of plug
 Periodic changing of pack
 Secondary surgery may be needed
Formation of tissue pockets that may lodge food material.
Risk of invagination and new cyst formation.

Marsupialization
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38. Modifications of Marsupialization

WALDRON’S METHOD (1941) OR PARTSCH II
 Two stage technique that combines the marsupialization and enucleation.
First marsupialization is performed and at a later stage, when the cavity becomes smaller, enucleation is
performed
INDICATIONS:
I.Close proximity to adjacent vital structures
II. Adequate bone fill has strengthened the jaw to prevent fracture during enucleation
III. Patient finds it difficult to clean the cavity
IV. For detection of any occult pathologic condition.
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39. Waldron’s method
ADVANTAGES
 Development of a thickened cystic lining,
which makes enucleation easier
Spares adjacent vital structures
Combined approach reduces morbidity
Accelerated healing process
Allows histopathological examination of
residual tissue.

DISADVANTAGES
 Patient has to undergo secondary surgery
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40. INDICATIONS: extensive cyst of the maxilla that occupies a large portion of the antrum.
Surgical procedure:
I.Gingival curvilinear incision is taken along the involved teeth. With vertical releasing incision
II.Mucoperiosteal flap is raised
III.Window is made by removing a portion of the cystic lining
IV.Freeing the cystic attachments from antrum
V.Intranasal antrostomy is performed
VI.Packing of the cystic –sinus cavity is done prevent the formation of a postoperative hematoma.
VII.Cavity is packed with
 Iodoform gauze coated with tincture benzoin
 Antral balloon or foley catheter
 Sterile polyethylene tube
VIII.Careful closure of the wound without tension must be ensured.
IX.Pack removed after 7 days
Marsupialisation by opening into the maxillary sinus or nose
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41. Marsupialisation by opening into the maxillary sinus or nose
Intranasal
antrostomy to allow drainage from the
maxillary sinus
Freeing the cyst from
its mucosal attachments
Cyst excision
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42. ADVANTAGES
 Primary closure
Cystic cavity is opened into the maxillary sinus or
nasal cavity, thereby reducing intracystic pressure
 Cystic cavity becomes lined with respiratory
maxillary
sinus or nasal cavity
 Adjacent structures are protected
 Restoration of the normal anatomy of the antral
space and nose.

DISADVANTAGES
Development of an oroantral or
oronasal fistula, if there is a
breakdown of the wound

Marsupialisation by opening into the maxillary sinus or nose
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43. Enucleation with primary closure
Enucleation involves complete removal of the cyst lining and its contents.
Covered by a mucoperiosteal flap and the space fills with blood clot, which will eventually organize
and form normal bone
Intraoral approach is usually the method of choice for enucleation.
 To gain maximum advantage it is usually completed by primary closure, and on occassion with open
packing.
INDICATIONS
I. Small cysts
II. Small or large cysts not endangering vital structures or risk of pathologic fracture
III.Cysts as odontogenic keratocysts that have a high recurrence rate
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44. Surgical procedures
I.Crevicular incision placed around the necks of
the involved teeth and the adjoining teeth on
either side
II.Releasing incisions are given at either ends,
which extend into the buccal sulcus
III.Mucoperiosteal flap elevated.
IV.Bone is then removed to expose the underlying
cystic lesion using burs and rongeur.
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45. V.The underlying cyst lining is now gently
detached from the cavity wall with the help of
curettes or Mitchell trimmer.
VI.Cystic lesion is removed and teeth that required
to be removed are now extracted
VII.Primary closure done after thorough irrigation.

Surgical procedures
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46. Specimen After enucleation
Cyst exposure Enucleation of cyst
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47. ADVANTAGES
Entire cystic lining is removed .
 Primary closure of the wound
Rapid healing.
Postoperative care is reduced
Thorough examination of the entire cystic lining
can be done.

DISADVANTAGES
In young people, tooth germ or unerupted teeth
involved with the cyst are extracted or removed
with the lining of the cyst.
 Pathological jaw fractures can occur in case of
enucleation of a large cyst.
The procedure endangers the adjacent vital
structures
Pulp necrosis and nonvitality of the adjacent
teeth
Enucleation with primary closure
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48. Enucleation with Open packing
INDICATION: Infected large cyst wherein primary
closure of the cyst might lead to breakdown of the
wound and interfere with healing.
Mucoperiosteal flap is raised and the cyst enucleated
But instead of primary closure, cavity is packed with
medicated gauze pack for 10 days.
 A change of pack is followed by the construction of
an acrylic plug.
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49. Enucleation and peripheral ostectomy

Enucleation of the cyst along with
removal of an inexact thickness of
surrounding bone by powered rotary
instruments.
Methylene blue dye can be used to
mark the bone
Asok kumar RS OMFS

50. Enucleation and primary closure with reconstruction/
bone grafting
INDICATION: Large cystic lesions that have
perforated and destroyed the cortical plates and
inferior border of the mandible
Reconstruct primarily with a stainless steel or
titanium reconstructive plate.
Occasionally, autogenous bone grafts, e.g. iliac
crest or costochondral grafts can be used for
reconstruction procedures replacing the lost bone.
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51. Enucleation and chemical cauterisation

After enucleation Carnoy’s solution is applied into the cavity.
Carnoy’s solution was first used as a medicament in surgery by Cutler and Zollinger in 1933.
It is a powerful fixative, haemostatic and a cauterising agent which penetrates cancellous
spaces in the bone and devitalises and fixes the left out epithelial remnant cells.
Its average depth of bone penetration of this solution is to a depth of 1.54 mm, nerve
penetration to 0.15 mm, and mucosa to a depth of 0.51 mm after 5 min of application.
COMPOSITION (CUTLER AND ZOLLINGER – 1933)
I.1 gm of ferric chloride
II.1 mL of glacial acetic acid
III. 3 mL chloroform
IV. 6 mL of absolute alcohol
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52. MODIFIED CARNOY’S SOLUTION :
Ferric chloride - 1gram
Glacial acetic acid - 1ml
Absolute alcohol - 6ml
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53. MECHANISM OF ACTION OF CARNOYS SOLUTION
Carnoy’s solution is a fixative agent.
Absolute alcohol hardens the tissue by shrinking it
Glacial acetic acid swells tissue and prevents overhardening
Chloroform increases the speed of fixation and
Ferric chloride acts as a dehydrating agent.
PRECAUTIONS
Chloroform is considered to be very hazardous and should be used in a well ventilated hood by wearing masks.
SIDE EFFECT
Neurotoxic—Nerve should be protected using bone wax
Necrosis of maxillary sinus
Better to use fresh solution


Enucleation and chemical cauterisation

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54. Cryotherapy
Liquid nitrogen has the ability to devitalise bone in situ.
It acts by direct damage from intracellular and extracellular ice crystal formation leading
to cell death.
It creates osmotic and electrolytes disturbance in cell.
After enucleation, cystic cavity is sprayed with liquid nitrogen twice for 1 min, with 5 min
thaw between freezes.
ADVANTAGES
Bony matrix is left in place to act as scaffold for new osteogenesis.
Bone grafts can be placed immediately to promote healing and decreasing risk of pathological
fracture.
Act as haemostasis agent and reduce scarring Asok kumar RS OMFS

55. TECHNIQUE: Schmidt and Pogrel (2001)
I.Enucleation of the cyst.
II.The surrounding tissues are then protected with sterile wooden
tongue blades and gauze
III.The cavity is sprayed with liquid nitrogen twice for 1 min (5-min
interval)
IV.Bone graft can be inserted
V.Mucosa is closed with tight sutures
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56. Resection

Resection can be either a marginal resection (surgical removal of a lesion intact and a small area of
uninvolved bone, maintaining the continuity of the bone) or a segmental resection (surgical
removal of a segment of the mandible without maintaining the continuity of the bone) in the
mandible
In maxilla the resections are classified as partial maxillectomy (alveolectomy) or subtotal or total
maxillectomies.
INDICATION: Severely thinned out bone and multiple perforations are present. Eg- ameloblastic
transformation within the cyst and OKC
Resections have the lowest recurrence rate (0%) but the highest morbidity rate
Reconstructive measures are necessary to restore jaw function and aesthetics.
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57. Marginal resection Segmental resection Partial maxillectomy
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58. Complications
Injury to inferior alveolar nerve
 Injury to adjacent teeth
 Oroantral communication
 Hematoma formation
 Fracture of the jaw (pathological)
 Infection prior to surgery may be acute or chronic
 Postoperative wound dehiscence
 Loss of vitality of teeth
 Neuropraxia in infected cysts
 Postoperative infection
 Recurrence
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59. Asok kumar RS OMFS