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)

Radicular 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

Residual cyst

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

Dentigerous cyst

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 asor

Enucleation is an alternative treatment with removal of tooth

Lateral periodontal cyst

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

Odontogenic keratocyst

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

orMarsupialization - 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

mixed 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 .

Local anesthesia

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

Thank you

Odontogenic cysts

Health & Medicine

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