Odontogenic cysts

Odontogenic Cysts
Dr. Amin Abusallamah

Outline
1. INTRODUCTION
2. CLASSIFICATION
3. CAUSES
4. HISTOPATHOLOGY
5. CLICAL FEATURES
6. RADIOGRAPHIC FEATURES
7. DIFFERENTIAL DIAGNOSIS
8. TREATMENT
9. PRINCIPLE OF TREATMENT
A. Types of Flaps.
B. Surgical removal the of the cyst .

INTRODUCTION
• A cyst is an epithelium-lined sac
containing fluid or semisolid material.
In the formation of a cyst, the epithelial
cells first proliferate and later undergo
degeneration and liquefaction. The
liquefied material exerts equal pressure
on the walls of the cyst from within.

INTRODUCTION
• Cysts grow by expansion and thus
displace the adjacent teeth by pressure.
May can produce expansion of the
cortical bone. On a radiograph, the
radiolucency of a cyst is usually
bordered by a radiopaque periphery of
dense sclerotic bone. The radiolucency
may be unilocular or multilocular

INTRODUCTION
• Odontogenic cysts are those which
arise from the epithelium associated
with the development of teeth. The
source of epithelium is from the
enamel organ, the reduced enamel
epithelium, the cell rests of Malassez or
the remnants of the dental lamina.

CLASSIFICATION
• Radicular cyst
• Residual cyst
• Dentigerous cyst (follicular)
• Primordial cyst
• Lateral periodontal cyst
• Odontogenic keratocyst
• Calcifying odontogenic cyst (Gorlin cyst)

Causes
• A periapical cyst develops from a preexisting
periapical granuloma, which is a focus of chronically
inflamed granulation tissue in bone located at the
apex of a nonvital tooth.
• Periapical granulomas are initiated and maintained
by the degradation products of necrotic pulp tissue

Histopathology
• The periapical cyst is lined by non
keratinized stratified squamous
epithelium of variable.
Transmigration of inflammatory
cells through the epithelium is
common, with large numbers of
(PMNs) and fewer numbers of
lymphocytes involved.

Histopathology
• The underlying supportive
connective tissue may be
focally or diffusely infiltrated
with a mixed inflammatory
cell population.

Clinical features
• Frequency:It is most common cystic lesion of jaw
comprising about approximately 52% of jaw cystic lesions.
• Age: found in 4th & 5th decades of life.
• Sex: It is more common in males 58% than females.
• Race: White patients more than Black patients.
• Site: It occurs with frequency of 60% occurs in maxillary
anterior region. Most commonly at apices of teeth.

Radiographic features
• Location: In most cases the epicenter of a radicular cyst is
located approximately at the apex of a nonvital tooth.
• Periphery and shape: The periphery usually has a well
defined cortical border. It will become ill-defined if infected.
• Internal structure: In most radicular cysts is radiolucent.
• Effects on surrounding structures: If a radicular cyst is
large, displacement and resorption of the roots of adjacent
teeth.

Differential Diagnosis
• Periapical abscess. Ill defined margin.
• Apical granuloma. may be difficult and in some cases impossible.
A round shape, a well-defined cortical border, and a size greater
than 2 cm in diameter are more characteristic of a cyst.
• Early stage of periapical cemental dysplasia. tooth are vital.
• Apical scar.
• Periapical surgical defect.

Treatment
Enucleation with preservation of tooth and RCT
with follow-up
Or
Extraction with curettage

Causes
• When the necrotic tooth is extracted but the cyst lining is
incompletely removed, a residual cyst may from months to
years after the develop initial extirpation If either or the a
residual cyst original periapical cyst remains
untreated, continued growth can cause significant bone
resorption and weakening of the mandible or maxilla.

Histopathology
Same like Radicular or periapical cyst

Clinical features
• A Residual cyst is a cyst that develops
• after incomplete removal of the original cyst.
• Usually asymptomatic.
• Unilocular, round or oval, well--defined, usually well
corticated.
• It can cause bone expansion and displacement of the adjacent
teeth.

• Location: In both jaw but more in the mandible. Found at
periapical location, in place of an extracted tooth.
• Periphery and shape: The periphery usually has a well defined
cortical border.
• Internal structure: In most cases the internal structure of
radicular cysts is radiolucent.
• Effects on surrounding structures: large cyst , displacement
and resorption of the roots of adjacent teeth may occur.

• Keratocyst: residual cyst has greater potential for
expansion compared with a keratocyst.
• Stafne developmental salivary gland defect is located
below the mandibular canal

Treatment
Enucleation if the lesion is small
Or
Marsupialization if the lesion is large

Causes
• Dentigerous cyst develops from proliferation of the
enamel organ remnant or reduced enamel
epithelium.

Histopathology
• The supporting fibrous connective
tissue wall of the cyst is lined by
stratified squamous epithelium.
In an uninflamed dentigerous cyst
the epithelial lining is
nonkeratinized and tends to be
approximately four to six cell
layers thick.

Histopathology
• On occasion, numerous mucous
cells, ciliated cells, and
rarely, sebaceous cells may be found
in the lining of the epithelium. The
epithelium-connective tissue
junction is generally flat, although in
cases in which there is secondary
inflammation, epithelial byperplasia
may be noted.

Clinical features
• Dentigerous cysts are most commonly
seen in association with third molars
and maxillary canines, which are the
most commonly impacted teeth. The
highest incidence of dentigerous cysts
occurs during the second and third
decades. There is a greater incidence in
males, with a ratio of 1.6 to 1 reported.

Clinical features
• Symptoms are generally absent, with
delayed eruption being the most
common indication of dentigerous cyst
formation. This cyst is capable of
achieving significant size, occasionally
with associated cortical bone expansion
but rarely to a size that predisposes the
patient to a pathologic fracture.

• Location: most common sites are mandibular third molar, maxillary
canine, maxillary third molar. Associated with the crown of an un-
erupted and displaced tooth.
• Periphery and shape: The periphery usually has a well defined
cortical border. Attached to the CEJ.
• Internal structure: most cases is radiolucent surrounding the crown.
• Effects on surrounding structures: Large cysts tend to expand the
outer plate (usually buccally).

• Hyperplastic follicle The size of the normal follicular space is 2
to 3 mm. If the follicular space exceeds 5 mm, a dentigerous
cyst is more likely.
• Odontogenic keratocyst ,does not expand the bone to the
same degree as a dentigerous cyst, is less likely to resorb
teeth, and may attach farther apically on the root instead of at
the cementoenamel junction.

• Ameloblastjc fibroma
• Cystic ameloblastoma The internal structure in both of them
differentiate
• Adenomatoid odontogenic tumors
• Calcified odontogenic cysts Both can surround the crown and
root of the involved tooth. Evidence of a radiopaque internal
structure should be sought in these two lesions.

Treatment
Marsupialization is strongly
recommended when tooth or
adjacent teeth prevented from as
or
Enucleation is an alternative treatment
with removal of tooth

Causes
• The origin of this cyst is believed to be related to proliferation
of rests of dental lamina.
• The lateral periodontal cyst has been pathogcnetically linked
to the gingival cyst of the adult; t the former is believed to
arise from dental lamina remnants within bone, and the latter
from dental lamina remnants in soft tissue between the oral
epithelium and the periosteum (rests of Serres).

Histopathology
• The close relationship between the two
entities is further supported by their
similar distribution in sites containing a
higher concentration of dental lamina
rests, and their identical histology. By
contrast, periapical cysts are most
common at the apices of teeth, where
rests of Malassez are more plentiful.

Clinical features
• Age : Adults
• Location : Lateral periodontal membrane especially
mandibular , cuspid and premolar area
• Usually asypmtomatic ; associated tooth is vital ;origin from
rests of dental lamina ;
• some keratocysts are found in a lateral root position
;gingival cyst be soft tissue of adult may counterpart

• Location: 50-75% of lateral periodontal cysts develop in the
mandible, mostly in a region extending from the lateral incisor
to the second premolar.
• Periphery and shape: well-defined radiolucency with a
prominent cortical boundary and a round or oval shape.
• Internal structure: usually is radiolucent.
• Effects on surrounding structures: Large cysts can displace
adjacent teeth and cause expansion

• Small OKC
• Mental foramen
• Small neurofibroma
• Radicular cyst at the foramen of an accessory pulp canal.
• The multiple (botryoid) cysts with a multilocular
appearance may resemble a small ameloblastoma.

Treatment
Enucleation with preservation of
adjoining teeth

Causes
• There is general agreement that OKCs develop from dental
lamina remnants in the mandible and maxilla. However, an
origin of this cyst From extension of basal cells of the
overlying oral epithelium has also been suggested.
• Genetic

Histopathology
• The epithelial lining is uniformly thin, generally ranging from 8
to 10 cell layers thick.
• The basal layer exhibits a characteristic palisaded pattern with
polarized and intensely stained nuclei of uniform diameter.
The luminal epithelial cells are parakeratinized and produce an
uneven or corrugated profile.

Histopathology
• Additional histologic features that may
occasionally be encountered include
budding of the basal cells into the C.T
wall and microcyst formation.
• The fibrous connective tissue
component of the cyst wall is often free
of inflammatory cell infiltrate and is
relatively thin.

Clinical features
• Age: Any age , especially adults
• Location : Mandibular molar ramus area favored ; may be
found dentigerous , in position of lateral root , periapical , or
primordial cyst
• OKCs are relatively common jaw cysts They occur at any age
and have a peak incidence within the second and third
decades.

• Location : The most common is the posterior body of the
mandible (90% posterior to the canines)and ramus (more
than 50%). This type of cyst occasionally has the same
pericoronal position asdentigerous cyst.
• Periphery and shape Usually : with a cortical border unless
become secondarily infected. The cyst may have a smooth
(round or oval shape), or it may have a scalloped outline.

• Internal structure
• most commonly is radiolucent.
• The cystic cavity contain keratin.
• In some cases curved internal septa may be present, giving
the lesion a multilocular Appearance.

• The effects on surrounding structures : It grow along the
internal aspect of the jaws, causing minimal expansion except
for the upper ramus and coronoid process, where
considerable expansion may occur. OKCs can displace and
resorbe teeth but to a slightly lesser degree than dentigerous
cysts. The inferior alveolar nerve canal may be displaced
inferiorly. In the maxilla this cyst can invaginate and occupy
the entire maxillary antrum

• Dentigerous cyst OKC
• Ameloblastoma, AB has a greater propensity to expand.
• Odontogenic myxoma, multilocular with fine straight septa.
• A simple bone cyst often has a scalloped margin and minimal
bone expansion.
• several OKCs are found, these cysts may constitute part of a
basal cell nevus syndrome.

Treatment
Wide (local) surgical excision for prevent the
recurrence
or
Marsupialization - the surgical opening of the
(KCOT) cavity and a creation of a marsupial-
like pouch, so that the cavity is in contact with
the outside for an extended period.

Calcifying
odontogenic cyst
(Gorlin cyst)

Causes
• COGs are believed to be derived from odontogenic epithelial
remnants within the gingiva or within the mandible or maxilla.

Histopathology
• Most COCs present as well-
delineated cystic proliferations with
a fibrous connective tissue wall lined
by odontogenic epithelium.
Intraluminal epithelial proliferation
occasionally obscures the cyst
lumen, thereby producing the
impression of a solid tumor.

Histopathology
• The basal epithelium may focally be quite prominent, with
hyperchromatic nuclei and a cuboidal to columnar pattern.
Above the basal layer are more loosely arranged epithelial
cells, sometimes resembling the stellate reticulum of the
enamel organ. The most prominent and unique microscopic
feature is the presence of ghost cell keratinization.

Histopathology
• The ghost cells are anucleate and
retain the outline of the
cell membrane. These cells
undergo dystrophic mineralization
characterized by fine basophilic
granularity, which may eventually
result in large sheets of calcined
material On occasion.

Clinical features
• Age: Any age
• Location : Maxilla favored ; gingiva second most common site
• No distinctive age gender, gender, or locationLucent to mixe
d radiographic patterns

• COCs may present as unilocular or multilocular radiolucencies
with discrete, welldemarcated margins. Within the
radiolucency there may be scattered, irregularly sized
calcifications. Such opacities may produce a salt-and-pepper
type of pattern, with an equal and diffuse distribution. In
some cases mineralization may develop to such an extent that
the radiographic margins of the lesion are difficult to
determine.

• Dentigerous cyst,
• OKC,
• Ameloblastoma. In later stages ,
• Adenomatoid odontogenic tumor,
• Ameloblastic fibroodontoma

Treatment
Surgical Enucleation is the preferred
therapy

Principle of Treatment
1. local anesthesia.
2. Types of Flaps.
3. Surgical removal the of the cyst .

Types of Flaps
1. Trapezoidal flap.
• Advantage : Provides excellent
access, allows surgery to be performed
on more than two teeth, produces no
tension in the tissues allows easy
reapproximation of the flap to its original
position.
• Disadvantages: Produces a defect in the
attachedgingiva

Types of Flaps
2. Triangular Flap.
• Advantage : Ensures an adequate blood
supply, satisfactory visualization, very
good stability .
• Disadvantages: Limited access to long
roots, tension is created when the flap is
held with a retractor, and it causes a
defect in the attached gingiva.

Types of Flaps
3. Envelope Flap.
• Advantage : Avoidance of vertical
incision and easy reapproximation to
original position
• Disadvantages: Difficult reflection
(mainly palatally), great tension with a risk
of the ends tearing, limited visualization
in apicoectomies, limited
access, possibility of injury of palatal
vessels and nerves, defect of attached
gingiva

Types of Flaps
4. Semilunar Flap.
• Advantage : Small incision and easy
reflection, no recession of gingivae
around the prosthetic restoration.
• Disadvantages: The incision being
performed right over the bone lesion due to
miscalculation, scarring in the anterior
area, difficulty of reapproximation , limited
access and visualization, tendency to tear.

Surgical removal the of the cyst
• Enucleation: This technique involves complete removal of
the cystic sac and healing of the wound by primary intention.
This is the most satisfactory method of treatment of a cyst
and is indicated in all cases where cysts are involved, whose
wall may be removed without damaging adjacent teeth and
other anatomic structures.

• The surgical procedure for treatment of a cyst with
enucleation includes the following steps:
1. Reflection of a mucoperiosteal flap.
2. Removal of bone and exposure of part of the cyst.
3. Enucleation of the cystic sac.
4. Care of the wound and suturing.

Panoramic radiograph showing an
extensive radicularlesion at the region
of teeth 22, 23, 24
Clinical photograph of case

Removal of maxillary cyst, with labial access. Incision for creating a trapezoidal flap.
Reflection of flap and exposure of surgical field.

Removal of bone at the labial aspect respective to the lesion.
Osseous window created to expose part of the lesion.

Removal of cyst from bony cavity, using hemostat and curette.
Surgical field after removal of lesion.

Operation site after placement of sutures.
Panoramic radiograph and clinical photograph taken 2 months after the surgical procedure.

• Marsupialization This method is usually employed for the
removal of large cysts and entails opening a surgical window
at an appropriate site above the lesion. In order to create the
surgical window, initially a circular incision is made, which
includes the mucoperiosteum, the underlying perforated
(usually) bone, and the respective wall of the cystic sac

• Marsupialization: After this procedure, the contents of the cyst
are evacuated, and interrupted sutures are placed around the
periphery of the cyst, suturing the mucoperiosteum and the cystic
wall together . Afterwards, the cystic cavity is irrigated with saline
solution and packed with iodoform gauze ,which is removed a week
later together with the sutures. During that period, the wound
margins will have healed, establishing permanent communication.
Irrigation of the cystic cavity is performed several times
daily, keeping it clean of food debris and avertinga potential
infection.

Marsupialization method. Circular incision includes mucosa and periosteum.
Exposure of buccal cortical plate and removal of portion of bone with round bur
Enlargement
of osseous
window with
rongeur

Exposure of cyst
after removal of
bone
Suturing of wound
margins with
cystic wall

Packing of cystic
cavity with
iodoform gauz
Cystic cavity after
insertion of
gauze

Odontogenic cysts

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