Odontogenic cysts
Introduction

Definition Cyst: A pathological cavity filled with fluid,
semi-fluid or gaseous contents, which is not created by
accumulation of pus. It may or may not be lined by
epithelium.

Cysts lined by epithelium are known as True Cyst. Ex–
Dentigerous cyst, Radicular cyst , Nasolabial cyst etc.

Cysts which are not lined by epithelium are known as False
cyst or pseudo cyst. Ex- Aneurysmal bone cyst, Traumatic
bone cyst, mucous extravasation cyst, Stafne’s bone cyst etc.

Depending on the origin of the epithelium lining true cysts we
categorize them as Odontogenic or Non odontogenic
cyst.
Basic components of cyst
Cystic capsule
Epithelial lining
Lumen
Classification of Odontogenic
cysts
Based on Etiology –
DEVELOPMENTAL
Dentigerous cyst
Eruption cyst
Odontogenic keratocyst*
Gingival cyst of newborn
Gingival cyst of adult
Calcifying odontogenic cyst*
Glandular odontogenic cyst
INFLAMATORY
Periapical cyst
Residual cyst
Paradental cyst
* Reclassified as Odontogenic tumors!!
Classification of Odontogenic cysts
•
Based On Cell Of Origin.
DERIVED FROM RESTS OF MALASSEZ
Periapical cyst
Residual cyst
DERIVED FROM REDUCED ENAMEL EPITHELIUM
Dentigerous cyst
Eruption cyst
DERIVED FROM DENTAL LAMINA (RESTS OF SERRES)
Odontogenic keratocyst
Gingival cyst of newborn
Gingival cyst of adult
Lateral periodontal cyst
Glandular odontogenic cyst
UNCLASSIFIED
Paradental cyst
Calcifying odontogenic cyst.
Dentigerous Cyst (Follicular
cyst).


Dentigerous cyst can be defined as an odontogenic cyst that
surrounds the crown of an impacted tooth; caused by fluid
accumulation between the reduced enamel epithelium and the
enamel surface.
Most common developmental odontogenic cyst.
Clinical Features: Always associated with the crown of an
impacted,embedded or unerupted tooth.
Commonest sites-mandibular & maxillary 3rd molar &
maxillary
cuspid areas.

Initially asymptomatic later on aggressive lesion causes-expansion
of bone ,facial asymmetry , displacement of teeth,HOLLOWING
OUT ENTIRE RAMUS.
Radiographic features: Cyst reveal a radiolucent area in 3
radiographic variationsCentral variety-crown enveloped symmetrically.
Lateral variety-enveloped on 1aspect
Circumferential variety-entire tooth is enveloped
Hisologic features:
Usually composed of thin connective tissue wall with layer
of stratified squamous epithelium lining the lumen.
Retepeg formation is generally absent.
Connective tissue wall is composed of a very loose fibrous
connective tissue .
Many islands of odontogenic epithelium.
RUSTON BODIES present within the epithelium-These are
linear,often curved,hyaline bodies of uncertain origin.
Content of lumen is thin,watery yellow fluid, occasionally
blood tinged.
 Potential complications – Ameloblastoma;
mucoepidermoid carcinoma; squamous cell carcinoma
 Treatment: Surgical excision or Marsupialization.

ERUPTION CYST




It is defined as an odontogenic cyst that surrounds a tooth crown tha
has erupted through bone but not soft tissue.
Whereas the dentigerous cyst develops around the crown of an
unerupted tooth lying in the bone, the eruption cyst occurs when a
tooth is impeded in its eruption within the soft tissues overlying the
bone.
Clinically visible as a soft fluctuant mass on the alveolar ridges.
This fluctuant cystic cavity if contains blood,appears purple in color
is called ERUPTION HEMATOMA


1
Odontogenic Keratocyst






It is derived from the remnants (rests) of the dental lamina, with
a biologic behavior similar to a benign neoplasm.
Recent classification by WHO had included these lesions in
neoplasms.
Named so because the epithelium produces so much of keratin
that it fills the lumen.
The cyst may occur at any age, from the very young to the very
elderly. The mandible is affected more frequently than the
maxilla. In the mandible, the majority of the cysts occur in the
ramus-third molar area.
The patient usually is asymptomatic but may have soft tissue
swelling, expansion of bone, pain.
The cyst may also get secondarily infected.

Roentgenographic features: Radiographically most OKCs
are unilocular presenting a well defined peripheral rim.
Scalloping of the border is also a frequent finding. Multilocular
radiolucent OKCs are also observed,

Histologic features: The lining epithelium is highly
characteristic, and is composed of:
◦ (1) a parakeratinized surface which is typically corrugated,
rippled or wrinkled
◦ (2) a remarkable uniformity of thickness of the epithelium,
usually ranging from 6 to 10 cells thick,
◦ (3) a prominent palisaded, polarized basal layer of cells
often described as having a “picket fence” or “tombstone”
appearance.
◦ No rete ridges are present; therefore, the epithelium often
sloughs from the connective tissue
◦ The connective tissue wall often shows small islands of
epithelium similar to the lining epithelium - satellite or
“daughter” cysts

The variant of OKC that produces only orthokeratin acts
somewhat differently than other OKCs. It has a considerably
less aggressive behaviour is different entitiy and should bear a
different name “orthokeratinized odontogenic cyst”

The most important feature of the odontogenic keratocyst is its
extraordinary recurrence rate
This high recurrance could be because of
◦ Thin and friable lining which makes it difficult to remove
intact
◦ It grows by perforating the bone (multilocular)
◦ Presence of satellite cysts in the wall
◦ Prolferative nature of the epithelium

JAW CYST-BASAL CELL NEVUS-BIFID RIB
SYNDROME

A hereditary condition, it is transmitted as an autosomal
dominant trait, it is associated with multiple odontogenic
keratocysts.

The syndrome is very complex and includes a great variety of
possible abnormalities. These may be briefly summarized as
follows: (I) cutaneous anomalies, including basal cell
carcinoma, other benign dermal cysts and tumors, palmar
pitting, palmar and plantar keratosis and dermal calcinosis; (2)
dental and osseous anomalies, including odontogenic
keratocysts (often multiple), mild mandibular prognathism, rib
anomalies (often bifid); (3) ophthalmologic
abnormalities, including hypertelorism with wide nasal
bridge; (4) neurologic anomalies, including mental
retardation, dural calcification, and (5) sexual
abnormalities, including hypogonadism in males and
ovarian tumors.
DENTAL LAMINA CYST OF NEWBORN










This Multiple,solitary,superficial raised nodules on edentulous alveolar
ridges of infants are also known as GINGIVAL CYST OF NEWBORN.
Resolve without treatment
Derive from rests of dental lamina
Consists of KERATIN producing epithelial lining.
Should not be confused with ‘BOHNS NODULES & EPSTEIN PEARLS
Clinical features:
Asymptomatic in nature
Become sufficiently large to become clinically obvious
Appear as small discrete white swellings on alveolar ridge.
Do not produce discomfort.
GINGIVAL CYST OF ADULT







Developmental Odontogenic cyst of the gingival soft tissue derived
from the rests of dental lamina
Occurs in free or attached gingiva
Arises from traumatic implantation of surface epithelium
May occur at any age
Lesion is a small , well circumscribed,painless swelling of gingiva
Resembles mucocele
Measures over 1 cm in diameter
Histologic features:
Epithelium is thick ranges from 1 simple flattened layer to several
layers.
Lining is the stratified squamous Epithelium.
Glycogen rich clear cells are present in the lining
Lesions are unicystic or polycystic
Dental lamina rests may be found in the connective tissue

LATERAL PERIODONTAL CYST




A slow-growing, non-expansile developmental odontogenic
cyst derived from one or more rests of the dental lamina,
containing an embryonic lining of 1 to 3 cuboidal cells and
distinctive focal thickenings (plaques).
This is the intrabony counterpart of the gingival cyst of adult.
An unusual form of cyst has been seen and known as botryoid
odontogenic cyst. This is a multilocular variant which looks
like a bunch of grapes.
Histologically the cyst is characterized by a thin,
nonkeratinized epithelium usually 1 to 5 cell layers thick, .
Focal thickened plaques of proliferating lining cells often
project into the lumen in areas.
CALCIFYING ODONTOGENIC
CYST
Also known as GORLIN CYST or CALCIFYING EPITHELIUM
ODONTOGENIC CYST
This lesion which exists in two forms
Type I - Cystic
type I A – simple Unicystic
type I B – ameloblastomatous proliferating
type I C – odontome producing type
Type II – Solid
The epithelial lining is made up of tall columnar cells and stellate
reticulum like cells. Foci of calcifications are seen and GHOST
CELLS are present.
The solid lesion is now seperated as a tumor and is known as
DENTINOGENIC GHOST CELL TUMOR
May occur in bone or in gingival soft tissue.
Periapical Cyst





Radicular cyst; Apical periodontal cyst; Root end
cyst
The periapical (radicular) cyst is the most common
odontogenic cyst.
It is an inflammatory odontogenic cyst
The usual etiology is an infected tooth, leading to necrosis of
the pulp. . Toxins exit at the apex of the tooth, leading to
periapical inflammation.
This inflammation stimulates the epithelial rests of Malassez,
which are found in the apical periodontal ligament, resulting
in the formation of a periapical granuloma that may be
infected or sterile. Eventually, this epithelium undergoes
necrosis caused by a lack of blood supply, and the granuloma
becomes a cyst (periapical cyst).

Radicular cysts can occur in the periapical area of any teeth, at
any age but are seldom seen associated with the primary
dentition. The majority of cases of apical periodontal cysts are
asymptomatic. The tooth is seldom painful or even sensitive to
percussion. This type of cyst is rarely is of such a size that it
destroys much bone, and even more rarely does it produce
expansion of the cortical plates.

The radiological image of the radicular cyst is a peri- or paraapical, round or oval radiolucency of variable size which is
generally well delineated and most likely with a marked
radiopaque rim.

Histologic features: the cyst is linied by nonkeratinized stratified
epithelium which shows proliferation in an arcading pattern.
Rushton bodies are seen
The connective tissue shows presence of inflammatory cells.
Cholesterol clefts are also seen.

