A Odontogenic cyst developing from the stellate reticulum which is formed in place of a tooth.

Etiology:

1. Develops through liquefaction and cystic degeneration of stellate reticulum of enamel organ before any calcified enamel or dentine is formed.
2. Usually it may develop from a normal tooth germ, which may be clinically missing from the arch or a supernumerary tooth germ or from dental lamina

Clinical features:

1. Accounts to 5-10 % of the Jaw Cysts
2. It is seen in place of a tooth in an Edentulous area
3. Location: Mandibular third molar region, Ramus region, Pre molar region, incisor region
4. May occur early in life but usually discovered later
5. Usually a tooth is missing
6. Varies in size
7. May expand bone and displace teeth

Radiographic Features:

1. Well demarcated , round or oval radiolucency with sclerotic or reactive border
2. Unilocular or multilocular
3. Seen below or between roots or near to the alveolar ridge
4. More in relation to third molars

Histopathology:

Based on Histology it is of 2 types:

• Keratinized type (more common)
• Non-Keratinized type (less common)

1. Connective tissue capsule shows parallel arrangement of collagen bundles, with varying compactness.
2. Epithelial lining is of stratified squamous – intact or interrupted.
3. Epithelium may also be sometimes non keratinized, with a prominent spinous layer and long and confluent rete ridges and with less conspicuous basal layer.
4. Sometimes the epithelium may be ortho keratinized with a thin to moderate spinous layer and a thin or flattened basal layer.
5. Sometimes the epithelium may also be para keratinized and corrugated in some areas or may also be uniform 6 – 10 cells thick, with a prominent basal layer – with the cells arranged in a PICKET FENCE pattern or TOMB STONE pattern
6. Rete ridge formation is not seen (cf. : odontgenic kerato cyst)
7. Inflammatory infiltrate may be variable.

Treatment:

Radical surgery – Curretage of Bone

Recurrence: Highly recurrent.

Odontogenic cysts

Mentioned here are the various classifications given by scientists for Cysts of Jaw:

1. WHO Classification
2. Shears Classification
3. Shafers Classification

WHO Classification is divided into 2 Types:

1. Developmental
2. Inflamatory

DEVELOPMENTAL:
I. Odontogenic:

1. Primordial ( Kerato ) cyst.
2. Gingival cyst.
3. Eruption cyst.
4. Dentigerous ( Follicular ) cyst.

II. Non Odontogenic:

1. Naso palatine duct ( Incisive canal ) cyst.
2. Globulomaxillary cyst.
3. Naso labial ( naso alveolar ) cyst.

INFLAMMATORY:

1. Radicular cyst.

Shear’s Classification

It is divided into 3 types:

1. Cysts of Jaw
2. Cysts associated with Maxillary Antrum
3. Cysts of the soft tissues of the Face, Neck and Mouth

Cysts Of Jaw:

EPITHELIAL CYSTS OF JAWS:

I. ODONTOGENIC:

a. Developmental:

1. Primordial (Kerato) cyst .
2. Gingival cyst of infants .
3. Gingival cyst of adults .
4. Lateral periodontal cyst .
5. Dentigerous cyst .
6. Eruption cyst .
7. Calcifying odontogenic cyst.

b. Inflammatory:

1. Radicular cyst .
2. Residual cyst .
3. Inflammatory collateral cyst.
4. Para dental cyst.

II. NON-ODONTOGENIC:

1. Nasopalatine duct cyst & Incisive canal cyst
2. Median palatine cyst
3. Median alveolar cyst
4. Median mandibular cyst
5. Globulomaxillary cyst
6. Naso labial (naso alveolar) cyst

a. Simple bone cyst:

1. Traumatic
2. Solitary
3. Hemorrhagic

b. Aneurysmal bone cyst.

Cysts Associated with the Maxillary Antrum

1.  Benign mucosal cyst .
2. Surgical ciliated cyst of maxilla.

Cysts of the Soft tissues of the Face, Neck and Mouth

1. Dermoid & Epidermoid cysts
2. Branchial cleft cyst (Lympho epithelial cyst)
3. Thyroglossal duct cyst
4. Anterior median lingual cyst
5. Oral cyst with gastro intestinal epithelium
6. Cystic hygroma
7. Cysts of the salivary glands
8. Parasitic cysts: Hydatid cyst, Cysticerous cellulosae

Shafers Classification

1. Primordial cyst .
2. Dentigerous cyst & Eruption cyst .
3. Periodontal cyst :
a. Apical periodontal cyst .
b. Lateral periodontal cyst .
4. Gingival cyst :
a. Gingival cyst of newborn(Dental lamina cyst)
b. Gingival cyst of adult .
5. Odontogenic kerato cyst .
(Jaw cyst , Basal cell nevus & Bifid rib syndrome)
6. Calcifying odontogenic cyst .

This is the most common developmental Odontogenic cyst.

Synonms: Follicular Cyst

Etiology:

• Develops by accumulation of fluid between the reduced enamel epithelium and the tooth crown after crown formation.
• By transformation of epithelium in the wall of the dental follicle and uniting with the follicular epithelium.

Location or Common Sites:

• Mandibular and Maxillary Third Molars and Maxillary cuspid regions
• Dentigerous cyst always is associated with the crown of a normal permanent tooth.
• Deciduous teeth are rarely involved.

Clinical Features:

It is always associated initially with the crown of an impacted, embedded or unerupted tooth

Dentigerous cyst may also be found enclosing a complex compound odontoma or imvolving a supernumerary tooth.

These are Solitary, Bilateral and Multiple cysts found usually in association with a number of syndromes like cleidocranial dysplasia and Maroteaux-Lamy Syndrome.

If Dentigerous Cyst turns into an Aggressive Lesion:

• Expansion of bone with facial asymmetry
• Extreme Displacement of teeth
• Severe root resorption
• Pain

Dentigerous Cyst may lead to Neoplasm:

• Dentigerous cyst is likely to cause Mural Ameloblastoma, which is a type of ameloblastoma.
• Localized areas of “Bud like” proliferations of cystic epithelial cells may be seen in few area, which are known as “Mural proliferations” and they indicate the development of “Ameloblastomas” which also proove the development of ameloblastoma from lining of dentigerous cyst.
• This complication will lead to difficulty in treatment of Dentigerous cyst.

Dentigerous Cyst involving an Unerupted Mandibular Third molar results in:

• Hollowing out of Entire Ramus upto the coronoid process
• Expansion of cortical plate
• Displacement of Third molar which sometimes gets compressed against the inferior border of the mandible.

Dentigerous Cyst surrounding impacted mandibular 3rd molar

Dentigerous Cyst involving an Unerupted Maxillary Cuspid:

• Expansion of the Anterior maxilla which resembles Acute Sinusitis or Cellulitis
• No pain unless Secondarily infected

Age:  Seen mostly in the second and third decades of life.

Sex:  Male : Female – 3:2

Radiographic Features:

• Radiolucent area is associated with un-erupted tooth crown.
• Radiolucency Symmetrically surrounds the tooth crown
• Radiolucent space will be more than 5mm

Dentigerous Cyst involving Impacted Mandibular canines

There are 3 Radiologic variants:

Central Variety: Crown is enveloped symmetrically, this pushes the crown towards the lower border of the Mandible

Lateral Type: Dilatation of the follicle on one aspect of the crown

Circumferential Type: The follicle expands in a manner which appears to envelope the Entire tooth. Sometimes the radiolucent area is surrounded by a thin sclerotic line representing bony reaction.

Histologic Features:

• Thin connective tissue wall with a layer of stratified squamous epithelium lining the lumen
• Thin layer of epithelium, 2 – 3 layers thick with no rete ridge formation, unless infected
• Presence of odontogenic epithelium in islands in the connective tissue wall – which may give rise to the development of AMELOBLASTOMA.
• •RUSHTON’S BODIES – peculiar, linear, often curved, hyaline bodies with variable staining of uncertain origin and unknown significance, but probably of hematogenous origin, found within the lining epithelium – especially in areas of inflammation.
• The cystic lumen contains thin watery yellow fluid, occasionally blood stained.
• Mandibular ones may show mucous secreting cells, sebaceous cells and lymphoid follicles sometimes.
• Rete Pegs are absent
• Connective tissue is thick and composed of fibrous tissue

Complications of Dentigerous Cyst

• Development of AMELOBLASTOMAS in the lining epithelium and in the islands of odontogenic epithelium.
• Development of MUCO EPIDERMOID CARCINOMA especially in the mandibular ones.
• EPIDERMOID CARCINOMA – due to keratin metaplasia in the epithelial component.

Treatment Of Dentigerous Cyst:

Treatment is determined by the size of the lesion

Smaller lesions: should be removed entirely- Enucleation

Larger lesions: With Bone loss and the cyst thinning the bone drastically- Marsupilisation and Surgical drainage is done.

Recurrence is rare unless there is neoplastic transformation.

The Syndromes are divided into 11 groups based on the type of diseases associated with it:

Click on the respective heading to go to get the detailed list of Syndromes.

1. Syndromes related to Developmental Disturbances.
2. Syndromes related to Benign and Malignant Tumors.
3. Syndromes related to Salivary gland tumors.
4. Syndromes related to Cysts and Tumors of Odontogenic Origin.
5. Syndromes related to Bacterial, Viral and Mycotic infections.
6. Syndromes related to Diseases of bones and Joints.
7. Syndromes related to Diseases of Blood.
8. Syndromes related to Diseases of Perodontium.
9. Syndromes related to Skin Diseases.
10. Syndromes related to Diseases Of Nerves and Muscles.
11. Syndromes related to Oral aspects of Metabolic Diseases.

Steven Johnson Syndrome:

• Severe bullous form of Erythema multiforme
• Erythema Multiforme involves skin, eyes, Oral Cavity and genitalia.

Crest Syndrome:

• Calcinosis Cutis
• Raynauds phenomenon
• Esophageal dysfunction
• Sclerodactyly
• Telangiectasia

Ehler Danlos Syndrome:

• Hyperextension of joints
• Hyper mobility of TMJ (Rubberman)

Goltz Gorlin Syndrome:

• Multi papillomas
• Atrophy of skin
• Polydactyly
• Sunken eye
• Sparse hair

Grinspan’s syndrome:

• Characterized by triad of Lichen planus
• Vascular Hypertension
• Diabetes Mellitus