Cysts/ dental implant courses

Odontogenic
Cysts of jaws
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 Introduction
 Classification
 Stages of cyst formation
 Odontogenic cysts

Greek word ‘kystis’ means sac or bladder, pouch , bag
Definition
 which is defined as pathological cavity Or pouch containing
fluid or semisolid material and may or may not be lined by
epithelium.
 By Killey and Key 1966 described as epithelium lined sac filled
with fluid or semisolid material.

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BY ROBINSON (1945)
From odontogenic tissues
Periodontal cyst –Radicular cyst
-Lateral type
-Residual type
Dentigerous cyst
Primordial cyst
From Non dental tissues
-Median cyst
-Incisive canal cyst
-Globulomaxillary cyst

BY SHEAR
A, Epithelial
1.Odontogenic
Inflammatory - Radicular cysts
-Residual cyst
-Inflammatory collateral cyst
Developmental
Dentigerous cyst
Eruption cyst
Gingival cyst of newborn
Gingival cyst of adult
Primordial cyst
Calcifying odontogenic cyst
Lateral periodontal cyst

2.Non odontogenic cyst
–Incisive canal cyst
-Median palatine cyst
-Median mandibular cyst
-Globulomaxillary cyst
-Nasolabial cyst
B. Non epithelial
-Simple bone cyst
- Aneurysmal bone cyst
C. Cyst associated with maxillary antrum
- Benign mucosal cyst of maxillary antrum
Sugical ciliated cyst of maxilla
D. Cysts of soft tissues of mouth,face,and neck
Dermoid and epidermoid cyst
-Bronchial cleft cyst
-Thyroglossal duct cyst
-Anterior medial lingual cyst
-Cystic hygroma
-Cysts of salivary glands

Origin of cysts
Cysts OE DL DO CO
M
REE
Dentigerous
cyst
√
Eruption cyst √
Gingival cyst √
Lateral
periodontal
cyst
√ √ √
Radicular cyst √

Formation of cyst
THREE PHASES IN THEIR FORMATION.
 Phase of initiation
 Phase of cyst formation
 Phase of cyst enlargement.

THEORIES OF CYST ENLARGEMENT
Various steps involved in the formation of a cyst seen to be as follows
Attraction of fluid in to cystic cavity
Retention of fluid in to the cavity
Production raised internal hydrostatic pressure
Resorption of surrounding bone with an increase in the size of bone cavity.

Bone resorbing factors
Bacterial products Keratinocytes Intracystic pressure
Interlukin 1 alpha mRNA
Increased secretion of MMPS 1 ,2, 3 and PG E2 ,E3.
Bone resorption

Factors involved in cyst formation
 PTCH is a trans-membrane receptor which binds to Sonic
hedgehog (SHH) protein to form a complex compound.
 PTCH , ensures limited programmed proliferation, fails if the
gene is altered by mutations or deletions.
 Result is uncontrolled cell proliferation, as well as a continuous
and useless synthesis of the non-functional PTCH protein.
Oral Oncology EXTRA (2005) 41, 284–288

 Lench et al. thought it possible that the OKC represented one of
the first clinical manifestations of homozygous inactivation of the
PTCH gene.
 Expression of the tumour suppressor PTCH and the oncogene
Shh may cause loss of PTCH function and so lead to OKC
development by stimulating continuous proliferation of dental
lamina cells of their normal degeneration.
Immunohistochemistry study results
PTCH positive PTCH negative
Odontogenic keratocysts 7 1
Dentigerous cysts 11 5
Radicular cysts 6 17
Oral Oncology EXTRA (2005) 41, 284–288

 Prostaglandin E2 and F2 alpha concentrations in aspirated cyst
fluid of 14 human dental cysts were measured by radioimmunoassay.
 Mean concentrations were found to be 22.0 ng PGE2/g cyst fluid
and 4.0 ng PGF2 alpha/g cyst fluid.
 Due to the high concentrations of PGE2 found in the cyst
material it is suggested that this prostaglandin may be one of the
bone resorbing factors to be responsible for the destruction of bone
periodontal diseases .
Rheumatol. 1979 May-Jun;38(5-6):182-5..

 Mast cells have been hypothesized to play a significant role in
pathogenesis of odontogenic cysts.
 Expansion of the jaw cyst involves destruction of the extra-cellular
matrix due to proteolysis of collagen fibers, osteoid – derived gelatin
and protein components of basement membrane.
 Mast cells contain numerous cytoplasmic granules, which are
degranulated into the extra-cellular space upon activation.
 In addition to preformed granule contents, activated mast cells can
synthesize de novo vasoactive mediators, for example, platelet –
activating factor, chemotactic mediators, and several
proinflammatory cytokines such as IL-1, IL-3, IL-6 and TNF – α.
Brazilian Journal Oral Sciences, Vol. 7, No. 27, Oct/Dec, 2008, pp. 1662-1665

Cont—
 Mast cells are a rich source of heparin and proteolytic enzymes, such as
tryptase, chymase and hyaluronic acid, which participate in connective
tissue breakdown in the capsule during normal metabolic turnover, as well
as in inflammation.
 Products released by mast cell activation and subsequent breakdown
products of connective tissue elements are released into the cyst lumen
increasing the hydrostatic pressure with subsequent enlargement.
Brazilian Journal Oral Sciences, Vol. 7, No. 27, Oct/Dec, 2008, pp. 1662-1665

Number of different molecules are identified in the cyst cavity or cyst wall, all of
which may contribute to osmotic activity of fluid.
Serum proteins
Glycosaminoglycans and Proteoglycans
Glycoproteins,collagenProteolytic enzymes
Cholesterol
Serum proteins
Soluble protein levels in odontogenic keratocysts are lower than those in radicular
and dentigerous cyst. Cyst fluid is rich in immunoglobulins.
Collagen
Collagen can be released and diffused in to the cyst lumen.
Result in proteolytic activity by specific collagenases.
Tumor suppressor gene P 53 is involved in OKC.

 There is a gp 38 altered gene expression in keratocysts.
 Increased expression of P53 protein in keratocysts is present.
P53 protein is a mutation product of tumor suppressor gene
P53.
 Tumor suppressor genes are expressed more strongly in
OKCS than in other cysts.
 Methylation of P16 gene is found in okcs along with P21 gene
and P27.
 Methylation of RBI gene was observed in dental follicles.

Histology
Outer wall of fibrous
connective tissue that
surrounds a central cavity
called the cyst
lumen.
On the inner aspect of the
wall is a lining of
epithelium, most commonly
stratified squamous
epithelium.

Features of jaw cyst in general
 Slowly growing swelling
 Usually painless unless secondarily infected or impinging on
nerve.
cortical plates are expanded.
 Egg shell cracking on palpation of large cysts
 Displacement and resorption of teeth may seen
 Occasionally pathologic fracture

General radiographic examination
Location :
 Cysts may occur centrally with in the bone in any location in the
maxilla and mandible but rare in condyle and coronoid process.
 Odontogenic cysts most often found in tooth bearing areas.
In mandible they originate above the mandibular canal.
 Odontogenic cysts may grow in to the maxillary antrum. Some
non odontogenic cysts may originate with in the antrum.

Periphery
Cysts that originate in the bone usually have a periphery that is well
defined, corticated.
Secondary infection or chronic infection can change this appearance in
to a thicker more sclerotic boundary.
Internal structure
Cysts often are radiolucent
long standing cysts have dystrophic calcifications which can give the
internal aspect a sparse particulate appearance,
some cysts that have scalloped periphery may appear to have internal
septa.

Thick condensed scelerotic
rim
Thick diffuse
Thin condensed
Punched out lesionwww.indiandentalacademy.com

Effects on surrounding structures
 Cysts grow slowly sometimes causes displacement and resorption of teeth.
 Areas of tooth resorption often has a sharp curved shape.
 Cysts can expand the mandible usually in a smooth curved manner and change
buccal or lingual cortical plate in to a thin cortical boundary.
 Displace the inferior alveolar canal in a inferior direction
 Invaginate the maxillary antrum maintain a thin layer of bone between that
separates the internal aspect of cyst from the antrum.

Cyst expansion
Tumor expansion

Contact visible Contact invisible
Contact
perforated

DEVELOPMENTAL CYSTS
DENTIGEROUS CYST (FOLLICULAR CYST OR PERICORONAL CYST)


Immunohistochemistry
Edamatsu et al (2005) examined the expression of FAS,bcl2 and
single stranded DNA in dental follicle and dentigerous cyst s to
clarify the possible role of apoptosis related factors in a sample of
follicles and in the pathogenesis of dentigerous cysts.
Edamatsu et al concluded that apoptosis related factors and
proliferation markers differed between dental follicles and
dentigerous cysts. Apoptosis and cell proliferation had a role in the
pathogenesis of the cysts.

Experimental studies on bone resorption
There is evidence that vital cyst tissue in culture releases a potent
bone resorbing factor that is predominantly a mixture of
prostaglandins (PGE2) and E3.
Data proposed by Harris indicated a lower levels of PGE2 released
by dentigerous cysts 12.2+/-9.4ng/mg than the radicular 16.6+/-
13ng/mg or by OKCs 20 +/-11ng/mg.

 PGE2 is one of the factor responsible for osteolytic effects.
 Interleukin 1 (IL1) may be produced by odontogenic cysts and
may account for raised levels of prostaglandin and collagenase
synthesis by the cyst capsules. IL1 released by the cysts leads to
stimulation of osteoclasts to resorb bone and the connective tissue
cells to produce prostaglandins that will be responsible for further
osteoclast activation.
 It also stimulates connective tissue cells to produce collagenase
which is involved in the destruction of bone matrix.

 Glycosaaminoglycans, predominantly hyaluronic acid but also
appreciable amounts of heparin and chrondrotoin sulphate 4 are
present in the fluids and walls of dentigerous cyst.
 Release of glycosaaminoglycans from the walls and their
diffusion in to the cyst fluid is thought to have an important role
in expansive cyst growth by increasing the osmolality of the cyst
fluid and hence raising the internal hydrostatic pressure of cyst.

Clinical features
 Develop around the crown of unerupted or supernumerary tooth.
 Most commonly occur in the second and third decades
 Male to female ratio of 2:1.
 Examination reveals a missing teeth or tooth with hard swelling
Occasionally resulting in facial asymmetry.


Sites - Mandibular and Maxillary third molars, Maxillary canines.
 According to Gilibisco cyst is most often in decreasing order like
third molars, canines, second premolars.
 Most cysts are solitary
 Bilateral or multiple cysts can occur in association with number
of syndromes including cleidocranial dysplasia and Maroteaux Lamy
syndrome.
 Expansion of cortical plates due to pressure extension may be
seen.

Rare case is presented in which a maxillary dentigerous cyst had
eroded the posterior wall of the right maxillary sinus into the
pterygo-palatine fossa causing facial pain due to pressure on the
nerves.
It had also eroded the lateral wall of sinus and into the oral cavity
and got infected resulting in foul smelling oral discharge
(Coll Physicians Surg Pak. 2006 Dec;16(12):783-5)
Dentigerous cyst forming a septal abscess is uncommon
A long period of impaction of mesiodentes may bring about
dentigerous cyst formation or movement of the mesiodentes.
Dentomaxillofacial Radiology (2004) 33, 125–127. doi: 10.1259/dmfr/68039278J

.
patient typically has no pain or discomfort.
But it has also been reported in younger age, as in
a 13 years old female by Shah N. J.(1994). 10 years
old
Indian Journal of Otolaryngology and Head and
Neck Surgery Vol. 54 No. 1, January - March 2002

A case of an unusally large dentigerous cyst in a 13 years old female patient presenting
with gross facial asymmetry involving the nose, eye and the mouth is reported.
Vol. 46, No. 4, Oct.—Dec. 1994 1JO
& HNS • 229

Radiographic features
Classically consists of a well corticated pericoronal radiolucency
which exceeds 5mm when measured from edge of crown to periphery
of lesion on radiographs.

Location :
o Epicenter of dentigerous cyst if found just above the crown of the
involved tooth, which usually is the mandibular or maxillary third
molar or the maxillary canines,
o cyst attaches to the cementoenamel junction.
o Cysts related to maxillary third molar may often grow in to the
sinus and may become quite large before they are discovered.
o Cyst attached to the crown of mandibular molars may extend a
considerable distance in to the ramus

Periphery and shape:
Well defined cortex with a curved or circular outline.
If infection is present the cortex may be missing.
Internal structure:
Internal aspect is completely radiolucent except for the crown of the
involved tooth.

Effects on surrounding structures:
 Cyst has a propensity to displace or resorb adjacent teeth.
 Commonly displaces the associated tooth in apical direction.
 In case of maxillary third molars and cuspids they may be pushed to the
floor of orbit and in mandibular third molars they may be pushed to the
condylar or coronoid region or to the inferior border of mandible.
 Floor of maxillary antrum may be displaced as the cyst invaginates the
antrum.
 In case of lower it may displace the inferior alveolar canal in inferior
direction.
 Expands the outer cortical boundary of the involved jaws.

HISTOLOGICAL FEATURES
 Composed of connective tissue wall with a thin layer of stratified squamous
epithelium lining the lumen.
 connective tissue wall is frequently thickened and composed of a very loose
fibrous connective tissue or of sparsely colonized myxomatous tissue.
 Inflammatory cells commonly infiltrate the connective tissue.
Shows rushton bodies with in the lining epithelium.
 Content of cystic lumen is usually thin, watery yellow and is occasionally blood
tinged.

Differential diagnosis
 Hyperplastic follicle,
 Radicular cyst of primary tooth.
 Odontogenic keratocyst
 Ameloblastic fibroma
 Cystic ameloblastoma,
 Adenomatoid odontogenic tumors
 Calcifying odontogenic cysts,


TREATMENT
 Small cysts are surgically removed which may include tooth as
well .
 Large cysts may be treated by marsupialization before removal.
Potential complications of dentigerous cyst
Ameloblasoma
Squamous cell carcinoma
Mucoepideroid carcinoma

ERUPTION CYST
 Odontogenic cyst with the histologic features of dentigerous cyst
that surrounds tooth crown that has erupted through the bone but not
soft tissue.
 Occur when the teeth is impeded in its eruption within the soft
tissue.
 Eruption cyst represents less than 1% of odontogenic cysts (Shear
1992).

Clinical features
 Soft fluctuant dome shaped bluish swelling on the alveolar ridge.
 Most commonly found in children and adults if there is a delayed
eruption.
 Deciduous and permanent tooth may be involved most
frequently anterior to first permanent molars.
 Usually painless unless infected.


Show soft tissue shadow since it is confined with in it and there is
usually no bony involvement.
Treatment
No treatment is necessary as the cyst often ruptures by itself.
Surgical exposure of tooth crown may lead to eruption process.

LATERAL PERIODONTAL CYST
 Intra osseous cyst which occurs on the root surface of a vital
teeth.
 Condition is unicystic but may appear as a cluster of small cysts,
a condition referred to as “Botryoid odontogenic cyst”.
• It is now widely accepted that the term lateral periodontal cyst
should be confined to cysts in the lateral periodontal position in
which an inflammatory etiology and a diagnosis of gingival cyst of
the adult and collateral keratocyst have been excluded on clinical
and histochemical grounds. (Shear and Pindborg ,1975: Wysocki et
al 1980,Cohen et al 1984: Altini and Shear ,1992)www.indiandentalacademy.com

Variant of lateral periodontal cyst is Botyroid odontogenic cyst which was
described by Weather and Waldron in 1973 for the multilocular radiographic
appearance of lateral periodontal cyst.
Clinical features
Sex: More common in males.
Age; occurs particularly between the 5th to 7th decades, with an average of
54 years.
Clinically it presents no signs or symptoms but occasionally a small swelling
of the gingiva or alveolar mucosa.
Asymptomatic and are less than 1 cm in diameter.
Detected during radiographic examination.

CASE REPORT
Case 1
A 54 year-old was treated for a residual cyst at the site of a 36, that has
been extracted twelve years before. The lesion was discovered as an
incidental finding by his dentist . Treatment consisted of enucleation.
Case 2
In May 2004, a 65-year-old man was referred because of a cystic
swelling distally of 33 in an edentulous part of the mandible. The 34 had
been extracted four years before. At that time there were no distinct
radiographic abnormalities. At oral examination a bluish, cyst-like
swelling was seen distally of 33 and measuring approximately 1.5 cm (
On the panoramic view a well-circumscribed radiolucency was observed
at the site of the previously extracted 34. A tentative clinicoradiographic
diagnosis of residual cyst was made.
Treatment consisted of enucleation.

Location
50-75% of lateral periodontal cysts develop in mandible,mostly in the
region of lateral incisor to premolar.
Occasionally in maxilla they develop in cuspid and lateral incisor
region.
Periphery and shape
Well defined radiolucency with a corticated border. Round or oval in
shape.
Rarely large cyst may have irregular outline.
If the cyst becomes secondarily infected it mimics
lateral periodontal abscess.

Internal structure
Totally radiolucent.
Botyroid variety may show multilocular appearance.
Effects on surrounding structure
Small cyst may efface the lamina dura of adjacent teeth .Large
cyst may displace the adjacent teeth.
Small OKCS
Mental foramen
Lateral radicular cyst
Lateral periodontal abscess

Histological features
 Epithelium lining is characterized by a thin, nonkeratinized
epithelium usually 1 to 5 cell layers thick, which resembles the reduced
enamel epithelium.
 Epithelial cells may exhibit a flattened cuboidal to columnar
morphology
 Epithelial lining exhibits focal thickenings or plaques, in
which glycogen rich “clear cells” can be demonstrated using
periodic acid Schiff stain.


 Connective tissue subjacent to the epithelium
exhibits a zone of hyalinization.
 Areas of separation of the epithelium from the
underlying connective tissue is a frequent finding.
Histological appearance of the lesion,
occasional clear cells
in basal layer (arrow) (Hematoxylin
and Eosin; original
magnification x 200).

Epithelial plaques

Treatment
Excisional biopsy or simple enuelation.

GOOD
MORNING

ODONTOGENIC KERATOCYST (OKC)
 Termed odontogenic keratocyst by Philipsen in 1956.
It accounts for 10% of all jaw cysts .
Non inflammatory odontogenic cyst that arises from dental lamina.
 It has got innate growth potential much as in benign tumor.
 Epithelial lining is distinctive because it is keratinized and 4-8 cells
thick.


 Primitive oral cavity, also called the stomodeum, is lined
with ectoderm. At its deepest portion it contacts the blind
superior aspect of the foregut, which is lined with endoderm.
 Union of these ectodermal and endodermal layers is
called the buccopharyngeal membrane.
 At approximately the twenty-seventh day of development,
membrane ruptures and the stomodeum becomes connected
with the foregut.
 The primitive oral cavity is therefore an ectodermal lined
structure beneath which lies the ectomesenchyme.

About 2 or 3 weeks after the rupture of the
Buccopharyngeal membrane, when the
embryo is about 6 weeks old, the first sign of tooth development
is seen.
Along the oral ectoderm a ridge of basal cells begin proliferation
at a more rapid rate than those cells adjacent to them.
Leads to formation of a band of epithelium that runs along the
crest of what will be the future dental arches.
Band of proliferating epithelium is called the dental
lamina.

 As cellular proliferation continues, unequal growth occurs at
various parts of the bud.
 A shallow depression occurs on the deep surface of the bud.
Concomitant to this morphologic change in the developing bud,
histologic differentiation occurs within the cells of the enamel
organ.
 Single layer of the cuboidal cells lining the convexity of the
enamel organ are known as the outer enamel epithelium .
 More columnar cells along the concavity of the organ are called
the inner enamel epithelium.
 As cells within the center of this epithelial enamel organ begin
to separate because of an increase in intercellular fluid, they
assume amore branched or reticular form area called the stellate
reticulum.

By the time the primary tooth germ has reached the bell
stage, other changes are also taking place. Lingual to the
enamel organ of this primary tooth germ, the dental lamina
is giving rise to the beginning of the enamel organ of the
permanent tooth.
Concurrently, the dental lamina of the primary tooth begins
to disintegrate.
As the lamina breaks up, the cells that compose it either
disappear or remain as small islands known as the
rests of Serres.

Etiology
 In the past OKC - originate from the primordium of a tooth before
mineralization.
 Later on OKC thought to - Arise from remnants of dental lamina.
-Basal cell layer of oral mucosal epithelium
-From stellate reticulum of the enamel
organ.
According to Stoelinga and Bronkhorst and Stoelinga and peters
OKCS may arise from proliferations of basal cells of oral mucosa.

Evidence of genetic factors in the etiology of sporadic
keratocysts
 There is a gp 38 altered gene expression in keratocysts.
 Increased expression of P53 protein in keratocysts noted.
 Tumor suppressor genes are expressed more strongly in
OKCS than in other cysts.
JOPM 2009( 38) 99-103

Clinical features
Occur in wide range
Age distribution is bimodal with a peak in the second and third
decades of life followed by another peak in the fifth decade of life or
later.
Sex: Males are commonly affected than females.
Symptoms:
OKCS usually have no symptoms, although
mild pain and swelling may occur.
Discharge may be present.

Site: OKCS develop more in mandible than maxilla.
In mandible majority of cases of develop in ramus and
third molar area and then anterior mandible.
In maxilla,the most common area is third molar area
followed by cuspid area.

Location:
• Most common location of OKC is the posterior body of mandible
(90% occur posterior to canines) and ramus (more than 50%).
• Epicenter is located superior to inferior alveolar canal.
Periphery and shape;
• Like other cysts OKCS shows cortical borders unless they have
become secondarily infected.
• Cyst may have smooth, round or oval shape identical to that of
other cyst or it may have a scalloped outline.

Internal structure
 Most commonly radiolucent.
 Presence of internal keratin does not increase radiopacity.
 In some cases curved internal septa may be present giving the
lesion multilocular .


 It as propensity to grow along the internal aspect of jaws
thus causing minimal expansion.
 Inferior alveolar canal may be displaced inferiorly.
 In maxilla the cyst may invaginate and occupy the entire
maxillary antrum.
 Displacement and resorption of teeth is slightly lesser
than the dentigerous cyst

ENLARGEMENT
Rate of growth:
 In a number of studies pointed that inflammatory exudates
had a negligible role in the enlargement of OKCs.
 As OKCS are intended to extend along the cancellous
componenent of the mandible without producing much
expansion of cortical plates, they frequently reached a large size
before they were diagnosed.
 Although Browne was of opinion that these cysts grew more
rapidly than other jaw cysts, Tollers view was that they grew at
a similar rate to other epithelial cysts of jaw.

Cont---
 Toller suggested that majority of OKCS take about 6
years to recur to a clinically significant size of more
than 1 cm diameter but with a wide time range, varying
from 1 to 25 years.
 Forssell estimated that the rate of growth of OKCS
varied from 2-14 mm a year, with a average of about
7mm and the rate was slow in patients over 50 years.

Role of osmolality in growth of the cysts
 Toller considered the part played the osmolality of the cyst
fluid in the enlargement of OKCs. He showed that there was
statistically significant difference between the mean
osmolality of the OKCs compared with the mean serum
osmolality .
 He suggested that osmotic differences between sera and
cyst fluids were not directly related to proteins in cyst fluids
and may be the result of the liberation of the products of cell
lysis which may not be proteins.
 Main on the other hand, felt that mural growth in the form
of epithelial proliferation was the essential process involved in
the enlargement of OKCs .

Role of inflammatory exudates in growth of the cysts
Inflammatory exudate has a negligible role in OKC
enlargement. Its cavity fluid contains low quantities of
soluble protein, composed predominantly of albumin and
only relatively small quantities of immunoglobulins.
Role of glycosaminoglycans in growth of the cysts
 Smith et al reported a series of 3 studies on the presence
and role of glycosaminoglycans in odontogenic cysts,
including OKCs.
Heparin sulphate showed a higher frequency and
abundance in the OKCs than the other cysts.

 Mast cells were wide in the connective tissue of all cyst types,
particularly adjacent to the epithelium and were probably the
source of heparin.
 Major source of glycosaminoglycans and proteoglycans in cyst
fluids is from the ground substance of the connective tissue
capsule , released as a result of normal metabolic turnover and
inflammatory degradation .
 Degranulating mast cells released heparin and hydrolytic
enzymes and latter facilitated the breakdown of the
glycosaminoglycans and proteoglycans.

In the third study, Smith et al extracted glycosaminoglycans
from fresh connective tissue capsules of OKCS, dentigerous
and radicular cysts.
In all cyst types hyaluronic acid was the predominant
glycosaminoglycan present as it was in the cyst fluids.
Heparin and chondrotin sulphate were present in the
substantial amounts.

HISTOLOGICAL FEATURES
 Composed of parakeratinized stratified squamous epithelium but
may rarely show foci of orthokeratinization.
 Compared to typical parakeratinization, orthokeratinized type
is rare.
 Epithelium is thin ranging from 6-8 cells thick .
 lacks retepegs which produces characteristic flat interface
between the epithelium and connective tissue.
 Separation of epithelium from the supporting connective tissue
of the cyst is common.
Caused by metalloproteinases mediated degradation of collagen in
the juxta epithelial regions.

 Cyst formed by stratified squamous epithelium that
produces orthokeratin (10%), parakeratin (83%), or
both types of keratin 7%.
 Epithelium is thin and mitotic activity is frequent,
 Lumen of the keratocyst may be filled with thin
straw coloured fluid or with a thicker creamy material
sometimes lumen contains keratin ,cholesterol and
hyaline bodies at the site of inflammation may also be
present.

 Parakeratinized areas shows surface corrugation and
there may be keratin in the lumen.
 Basal layer is composed of columnar or cuboidal cells.
 Connective tissue wall is composed of fibrous tissue rich
in mucopoly saccharides and free of inflammation.
 Small daughter or satellite cysts may be present.

Histological features of orthokeratinized epithelium;
- Orthokeartinized stratified squamous epithelium
without evidence of parakeratinization, Contain orthokeratin
in the lumen.
- Basal cells are cuboidal to squamous and rarely consisted
of single cell type
-Orthokeratinized OKCS has more limited growth potential
and lower recurrence rate.

DIFFERENTIAL DIAGNOSIS
Dentigerous Cyst
Ameloblastoma
Odontogenic Myxoma
Traumatic bone cyst

Management
 Enucletaion
 Resection
 Curettage or marsupilization to reduce the size of large cyst before
surgical excision.
 Cryosurgery.
Complete removal of cystic lining is done to reduce the chance of
recurrence.

 Recurrence rate varies from 3-62%.
 Recurrent lesions usually develop within first 5 years but
may be delayed as long as 10 years.
 Forssell and Kahnberg observed that recurrence were
more frequent 63% with cysts in patients with basal cell
nevus syndrome than with cysts without this syndrome37%.

JAW CYST –BASAL CELL NEVOID SYNDROME-GORLIN AND
GLOTZ SYNDROME
• Syndrome was first described by Binkley and Johnson in 1951.
• Gorlin and Goltz found relationship between this syndrome and
multiple odontogenic cyst.
• Hereditary autosomal dominant trait with high penetrance and
variable expressively.
• Caused by mutation in patched(PCTH), tumor suppressor gene
that has mapped to chromosome 9q 22.3.

Clinical features
Includes variety of abnormalities like
Cutaneous anomalies : Includes basal cell carcinoma,
palmer and planter keratosis and dermal calcinosis.
Dental and osseous anomalies: Multiple odontogenic
keratocysts, mandibular prognathism, rib anomalies like
bifid ribs, vertebral anomalies.
Ophthalmologic abnormalities : Includes hypertelorism
with wide nasal bridge,congenital blindness and strabismus.
Neurological anomalies : Includes mental retardation, dural
calcification and congenital hydrocephalus

GINGIVAL CYST OF INFANTS (DENTAL
LAMINA CYST)
 Gingival cysts are small, almost multiple white nodules
found on the alveolar ridges of newborn and infants up to
about 3 months of age.
 Derived from remnants of dental lamina and resolves
without treatment.
FROMM classified oral embryological inclusion cysts as
–Epistein pearls
-Bohns nodules
-Dental lamina cysts.

Epistein pearls
 keratin filled nodules found along the midpalatine raphe
 Derived from entrapped epithelial remants along the line of
fusion.
Bohns nodules
Cysts arising from remanants of mucous glands in the palate
away from the midline,most numerous at
the junction of hard and soft palate.

Dental lamina cyst
Cyst arising from remnants of dental lamina on the crest of
alveolar ridge.
Clinical features– Appears as small discrete white swellings
of alveolar ridge,multiple occassionaly solitary in number.

Cysts with a thin epithelial lining which lacks rete processes.
Lumen is filled with degenerated keratin.
Treatment
No treatment is required.
Cysts are superficial and with in weeks they will ruptures
and spill their content in to the oral or pharyngeal
environment

GINGIVAL CYST OF ADULT
Uncommon cyst which may be developmental or acquired in origin.
It occurs on free or attached gingiva.
Pathogenesis
May arise from odontogenic epithelial cell rests.
Or by traumatic implantation of surface epithelium.
or by cystic degeneration of deep projections of surface epithelium
(Ritchey and Orban, 1953).

 Very rarely, they may be derived from glandular elements
(Traeger, 1961).
 Most favoured theory of origin is from odontogenic
epithelial cell rests derived from the dental lamina, although
Shafer et al. (1983) felt that cysts arising from traumatic
implantation of surface epithelium may occur.
 Wysocki et al. (1980), who favoured origin of these cysts
from the dental lamina, have suggested that either unicystic or
polycystic forms may develop depending on whether single or
multiple enlarged epithelial cell rests of the dental lamina break
down.

Wysocki et al. (1980), who favoured origin of these cysts from
the dental lamina, have suggested that either unicystic or
polycystic forms may develop depending on whether single or
multiple enlarged epithelial cell rests of the dental lamina break
down.
Theory postulates that the lateral periodontal cyst develops
from reduced enamel epithelium before eruption of the tooth
and the gingival cyst of adults from junctional epithelium
(reduced enamel epithelium) after eruption of the tooth.

Clinical features; Gingival cyst may occur at any age but
more common in adults in 5th and 6th decades of life.
Sex- Occurs more in males.
Site- More common in mandible in premolar and canine
region.
It presents as painless swelling less than 1cm in size on the
labial aspect of attached or free gingiva.
Appearance-Surface may be smooth and color may appear as
that of normal gingival or bluish or red when it is blood filled
as a result of trauma. Lesions are soft, fluctuant and
adjacent teeth are vital.

There may be no radiographic change or only a faint round
shadow indicative of superficial bone erosion.

Histology
 Gingival cysts in the adult have a variable histological
pattern.
 Extremely thin epithelium, closely resembling reduced
enamel epithelium, with 1–3 layers of flat to cuboidal cells
containing arkly staining nuclei.
 In others, the epithelial lining may be of a rather thicker,
stratified, squamous nature without rete ridges.
 Many of the epithelial cells have pyknotic nuclei and
show perinuclear cytoplasmic vacuolation.

The attachment of the epithelium to the underlying connective
tissue is tenuous and easily peels off, leaving epithelial
discontinuities.
Fibrous connective tissue wall is usually relatively
un inflamed except close to the junctional epithelium where a
chronic inflammatory cell infiltrate may occur; and rarely may
contain small epithelial islands.
Lesion is usually unicystic, but occasional multicystic variants
are may occur.
Treatment- Surgical excision.

Good
morning

CALCIFYING ODONTOGENIC CYST
(CALCIFYING KERATINIZING ODONTOGENIC CYST, GORLIN
CYST,CALCIFYING GHOST CELL ODONTOGENIC TUMOR)
Rare variety which was initially characterized by Gorlin and
associates.
WHO 1992 renamed as calcifying cystic odontogenic tumor.
Calcifying odontogenic cyst can be classified mainly in to two
types.
 Cystic lesion
 Solid neoplastic lesion

Clinical features
 Wide age distribution that peaks at 10-19 years of age with mean
age of 36 years.
 second peak incidence occurs during the seventh decade.
 Appears as slowly growing painless swelling of jaw, occasionally
the patient may complain of pain.
 In some cases expanding swelling may destroy the cortical
plates
 Discharge may be present.
 Aspiration yields a viscous granular yellow fluid.

Location: At least 75% of calcifying odontogenic cyst occur in bone
with a nearly equal distribution between the jaws.
75% occur anterior to the first molar especially associated with
cuspids and incisors.
Periphery and shape
well defined and corticated with a curved cyst like shape to ill
defined and irregular.
Internal structure
completely radiolucent or it may show evidence of small foci of
calcified material that appears as white fleckes or small smooth
pebbles, or it may show larger solid amorphous masses.

• 20-50% case of cyst is associated with tooth ( commonly cuspid)
and impedes its eruption.
• Displacement and resorption of roots may occur.
• Perforation of cortical plates may occur with enlarging lesions.

Dentigerous cyst
Adenomatoid odontogenictumor
Ameloblastic fibroodontoma
Calcifying epithelial odontogenic tumor

• Basal layer consisting of palisaded columnar or cuboidal cells
and hyperchromatic nuclei,which are polarised away from the
basement membrane.
• Epithelium may be a regular 6–8 cells thick and in some parts
that may be very thin
• Budding from the basal layer into the adjacent connective
tissue and epithelial proliferations into the lumen are
frequently seen.

 Most remarkable feature of the COC is the presence of ghost cells
which have been compared with those found in the calcifying
epithelioma of Malherbe in the skin.
 Ghost cells are found in groups, particularly in the thicker areas of
the epithelial lining.
 Ghost cells are enlarged, ballooned, ovoid or elongated elliptoid
epithelial cells.
Eosinophilic and although the cell outlines are usually well
defined, they may sometimes be blurred


 A few ghost cells may contain nuclear remnants but these are in
various stages of degeneration and in the majority all traces of
chromatin have disappeared leaving only a faint outline of the original
nucleus.
 Ghost cells represent an abnormal type of keratinization and have
an affinity for calcification.
 Calcifications begins as basophilic,intracellular granular
calcifications which enlarge and coalesce to form the relatively large
dystrophic calcifications.

Treatment
Conservative surgical approach.
Depending up on the site and size of the lesion and the presence if
any other odontogenic elements (odontome, ameloblastoma like
epithelium,ameloblastic fibroma) simple enuleation or more
extensive excision may be required.

GLANDULAR ODONTOGENIC CYST
(SIALO-ODONTOGENIC CYST, MUCOEPIDERMOID
ODONTOGENIC CYST)
 Sialo odontogenic cyst was reported by Gardner.
 Mucoepidermoid odontogenic cyst” because of presence of secretary
elements and stratified squamous epithelium.
 Intrabony and multilocular radiographically with a cystic spaces
lined by nonkeratinized stratified squamous epithelium similar to
reduced enamel epithelium.

Clinical features
Frequency: The glandular odontogenic cyst is a rare lesion.
It accounts about 0.2 % of cyst.
Age; wide range of age between 10-90 years with peak in sixth decades.
Sex- more common in females.
Site- More common in mandible than maxilla and more commonly
occurs in anterior mandible.
Patient may present with painless swelling of jaws or face.
Growth is slowly progressive and locally aggressive.

 Well defined multilocular or unilocular radiolucency.
 Root resorption and displacement of adjacent teeth may be
seen.
 Expansion and thinning of cortical plates with perforation may
be seen.

Epithelial lining is non keratinized stratified squamous epithelium
of variable thickness with a chronic inflammatory infiltration of
the connective tissue wall.
Microcysts open on the surface of epithelium giving a papillary or
corrugated appearance.

Numerous goblet cells may be present, mainly in the
superficial part of the epithelium.
Occasionally, the epithelium is thinner, similar to reduced
enamel epithelium.
Epithelial thickenings or plaques may be present either in this
thin epithelium or in the stratified squamous epithelium.
Interface between the epithelium and connective tissue is
flat.

Treatment
Enucleation
o If the lesion are completely enucleated, further surgery is not
indicated because recurrence is unlikely.
o Patients should be followed for at least 3 years and preferably as
long as 7 years.
Marsupialisation is recommended if the lesion approach vital
structures.
For large mulitilocular lesions major treatment modalities are
indicated.
Include peripheral ostecotomy,Marginal resection or partial jaw
resection.

INFLAMMATORY CYSTS
Comprise a group of lesions that arise as a result of epithelial
proliferation due to inflammatory causes
Types of inflammatory cysts
 Radicular cyst
 Residual cyst
 Inflammatory collateral cyst, Pardental cyst, Mandibular
infected cyst

RADICULAR CYST
(PERIAPICAL CYST, APICAL PERIODONTAL CYST)
 Most common of all odontogenic cysts.
 Accounts 70% of cysts
 Classified as an inflammatory cyst because it is thought that
inflammatory products initiate the growth of epithelial
components.

Epithelial lining of radicular cysts may synthesise cytokines that are known to
be important in bone resorption.
Endotoxins initiate an inflammatory reaction
resulting in production of cytokines with proinflammmatory and bone
resorbing activites.
Major cytokines identified are IL1,IL6.
Local changes in the supporting connective tissue may contribute to
activating the cell rests (Grupe et al., 1967).
Decrease in oxygen and increased carbon dioxide tension.
local reduction in pH and was accompanied by proliferation of the rest cells of
Malassez.

Clinical features
 Radicular cyst is the most common type of cyst in the jaws.
 Age-Incidence is greater in third and sixth decades.
 Sex-More common in males than females in the ratio 1.4:1.
 Site-About 60% occurs in maxilla, 40% occurs in mandible.
More common in maxillary anterior region.

 Arise from non vital tooth ( tooth that have lost vitality due
to deep caries or deep restoration or previous history of trauma.
 Most cysts are symptomless and are discovered when
periapical radiographs are taken for non vital tooth.
 Patients may complain of swelling of jaws, slowly enlarging
swellings.
 If it becomes secondarily infected pain may present.

 On palpation swelling may feel bony hard if cortex is intact
May demonstrate a crackling sound as the cortical plates
becomes thinned.
 Swelling is rubbery and fluctuant if the outer cortex is lost.

Location: Epicenter is located approximately at the apex of
non vital tooth,
Occasionally it appears on the mesial or distal surface of
tooth root, at a opening of accessory canal or infrequently in
deep periodontal pockets.
About 60% found in maxilla around incisors and canines.
They also form in relation to non vital deciduous molars.

Periphery and shape
 well defined with a cortical border
 If secondary infection is present, the inflammatory reaction of
surrounding bone may results in loss of cortex or alteration of the
cortex in to a more sclerotic border .
 Outline of radicular cyst is usually curved or circular.
Internal structure
In most cases the internal structure of cyst is radiolucent.
Occasionally, dystrophic calcifications may develop in long
standing cysts.

 Large cysts cause displacement and resorption of roots of adjacent
teeth.
 Resorption pattern may be curved outline.
 cyst may invaginate the maxillary antrum ,but there should be
evidence of cortical border between the contents of cyst and the
internal structures of the antrum.
 Outer cortical plates may be expanded in a smooth curved or
circular shape.
 Displacement of mandibular canal in an inferior direction may be
present.

Periapical granuloma
Periapical scar
Surgical defect
Periapical cemental dysplasia
Traumatic bone cyst
Mandibular infected buccal cyst

RESIDUAL CYST
 Cyst that remains after incomplete removal of original cyst.
 Shafer and collegues as well as Shear have stated that the
term residual cyst is frequently applied to an apical periodontal
cyst which remains after or develops subsequent to extraction
of an infected tooth.
 Shafer and associates also stated that the term can be
applied to any cyst of the jaw that remains following surgery.

Clinical features
 Asymptomatic and often discovered on radiographic
examination of edentulous area.
 Some expansion of jaw may be present.
 Pain is present in case of secondary infections.
 Cysts are usually less than 1cm in size.
 Age- Highest incidence over 20 years of age with an average age
of being 52years.
 Site-Alveolar process and body of jaw bone in edentulous areas.
 Maxilla is more commonly involved than mandible.
 Sex- Male predominance in the ratio 3;2.

Location: They occur in both jaws .Epicenter is positioned in a
periapical location.
In mandible the epicenter is above the inferior alveolar canal.
Periphery and shape
Residual cyst has a cortical margin unless it becomes secondarily
infected.
I t is oval or circular in shape.

Internal structure
Internal aspect is radiolucent. Dystrophic calcifications
may be present in long standing cases.
Causes displacement and resorption of adjacent teeth.
Cortical plates may be expanded.
In some cases cyst may invaginate the maxillary antrum
or depress the mandibular canal.

Odontogenic keratocyst
Stafnes developmental cyst
Compared to OKC residual cyst has greater potential for
expansion.
The epicenter of stafnes cyst is located below the mandibular
canal.
Treatment
Surgical removal or marsupialization or both if the cyst is large.

PARADENTAL CYST
(Buccal bifurcation cyst (bbc), Mandibular infected cyst.
Inflammatory collateral dental cyst)
 Both paradental and collateral cyst have same characters.
Paradental cyst is of inflammatory origin and that it arises from
odontogenic epithelium.
Craig suggestes that either the cell rests of malassez or the reduced
enamel epithelium may provide the cells of origin.

 One theory holds that inflammation is the stimulus.
 WHO includes these cysts under the inflammatory cysts
.In infected pardental cyst ,the source of inflammation is the
infected operculum around an erupting tooth usually a
mandibular third molar.

Clinical Features
Frequency – It represents 3.0% of all cysts 3.7% of odontogenic cysts.
Age – BBC most common in second decade & infected paradental cyst
common in third decade.
Sex – more common in males than females. 1:0.4 to 1: 0.7
Common in whites versus black people living in Africa.

Site and clinical presentation
Over 60% of all para dental cyst involve the mandibular third
molar & there is usually a history of recurrent or persistent
pericoronitis.
Lesions are most often located in a buccal or distobuccal location
and cover the root surface usually involving the bifurcation.
The tooth is always vital.
There may be lack or delay in eruption of a mandibular first or
second molar.

•On clinical examination the molar may be missing or the
lingual cusp tip may be abnormally protruding through the
mucosa, higher than the position of buccal cusps.
•The first molar is involved more frequently than second
molar.
•A hard swelling may be present buccal to involved molar

Radiographic Features
If paradental cyst associated with third molars there is
usually a distal as well as buccal radiolucency.
In all types of para dental cyst the periodontal ligament
space is not widened.
Location –Mandibular first molar is the most common
location of BBC followed by the second molar.
Cyst occasionally is bilateral.
It is always located in the buccal furacation of affected
molar.

Periphery and Shape:
In some cases the periphery is not readily apparent,
and the lesion may be a very subtle radiolucent
region superimposed over the image of the roots of
the molar.
In other cases the lesion has a circular shape with a
well defined cortical border.
Internal structure : Radiolucent.

Most striking character is the tipping of the involved
molar so that the root --tips are pushed into the lingual
cortical plate of mandible.
-Occlusal surface is tipped towards the buccal aspect of
mandible.
-Large cyst may displace or resorb the adjacent teeth.
-Periosteal bone formation is seen on the buccal cortex
adjacent to the Involved teeh.

Treatment
BBC is usually removed by conservative curettage.
Involved molar should not be removed.
BBC do not recur.

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