CYST / CLASSIFICATION / DIAGNOSIS SURGICAL MANAGEMENT DEFINITION; A cyst is a pathological cavity having fluid, semifluid, or gaseous contents and which is not created by the accumulation of pus. It is frequently ,but not always lined by epithelium. [KRAMER—1974]

EPITHELIAL ORIGIN ODONTOGENIC EPITHELIAL NON-ODONTOGENIC EPITHELIAL 1.DEVELOPMENTAL a—Primordial cyst / KERATOCYST b—Dentigerous cyst /FOLLICULAR c—Lateral periodontal cyst, BOTRYOID d—Calcifying odontogenic cyst, GORLIN CYST 2.INFLAMMATORY a—Radicular cyst, APICAL/LATERAL PERIODONTAL b—Residual cyst 1.FISSURAL a—Median mandibular b—Median palatal c—Globulomaxillary 2. { INCISIVE CANAL / NASOPALATINE DUCT / MEDIAN ANTERIOR MAXILLARY } CYST

NON-EPITHELIAL CYSTS 1.Solitary bone cyst / TRAUMATIC 2.Aneurysmal bone cyst 3.Stafne’s bone cavity Depending on the presence or absence of epithelial lining, they can be True cyst: Lined by epithelium Pseudo cyst: Not lined by epithelium

General features of jaw cysts Cawson’s essentials of oral medicine & oral pathology 7th edition

INVESTIGATIONS Radiographic examination Vitality tests Contrast studies Aspiration Biopsy CT/MRI

ODONTOGENIC KERATOCYST Incidence: 3-11% of all odontogenic cysts Age : 10 – 40 years Sex : Males > females Site : Mandible [ post. Body & ascending ramus ] Symptoms : painless – small painful - if secondarily infected Other ftrs : Usually asymptomatic, paresthesia can occur in case of pathological fracture / Aggressive Expansion : Antero-posterior expansion, through medullary spaces, less bony expansion Aspirate : Cheesy keratin content Teeth : Occasionally un-erupted teeth

RADIOGRAPHIC FEATURES Keratocyst can be unilocular or multilocular TYPICAL “ SOAP-BUBBLE” APPEARANCE Margins can be smooth or scalloped, which suggest an unequal growth activity.

CYST CONTENTS ASPIRATE: O.K.C contains a dirty white or straw coloured viscoid suspension of keratin, which has an appearance of pus, but without offensive smell. Smear should be stained & examined for keratin cells. ELECTROPHORESIS, will reveal low protein content, which is mostly albumin. Total protein is found to be below 4gm/100ML.

MANAGEMENT Treatment should be based on PROPER CLINICAL ASSESSMENT, ACCURATE DIAGNOSIS, APPROPRIATE TESTS OF THE CYSTIC ASPIRATE. MARSUPIALIZATION is incorrect principle in treatment of O.K.C, because of their high incidence & tendency of recurrence. Care should be taken to ensure that all fragments of the extremely thin lining are removed. AGGRESSIVE TREATMENT Enucleation with curettage is the best treatment for OKC. Resection

DENTIGEROUS [FOLLICULAR] CYST It results because of enlargement of the follicular space of the whole or part of the crown of an impacted or an un-erupted tooth & is attached to the neck of the tooth. It involves teeth of the adult dentition or occasionally supernumerary teeth. PATHOGENESIS Dentigerous cysts develop by accumulation of fluid between the reduced enamel epithelium or within the enamel organ itself of unerupted or impacted teeth. Another possibility for development of cyst, is degeneration of STELLATE RETICULUM at an early stage of development and is likely to be associated with ENAMEL HYPOPLASIA. In case of a DILATED FOLLICLE, pericoronal width of more than 3—4 mm is considered as a cyst.

CLINICAL FEATURES INCIDENCE; More commonly seen than primordial cysts. AGE; 1ST ,2ND , & 3RD decades of life and gradually it declines in occurrence. SEX; Equal in both sexes, slight more in male’s SITE; It occurs more frequently in mandible than in maxilla Late erupting teeth are the most frequently involved in descending order as; Lower 3rd molars, upper cuspids, upper 3rd molars, & lower bicuspid teeth. Dentigerous cysts have the potential to attain a large size, often it is pronounced facial asymmetry or the problem of ill-fitting dentures that forces a patient to seek treatment. Pain may be present if secondarily infected.

Clinically, a tooth from the normal series, will be found to be missing, unless the cause is a supernumerary tooth. The lateral expansion causes a smooth, hard, painless, prominence, later as the cyst expands the bone covering the center of the convexity becomes thinned & can be indented with pressure on palpation, with further expansion. This fragile outer shell of bone becomes fragmented and the sensation imparted & sound produced on palpation over the area is described as “EGG-SHELL CRACKLING”. Still later the cyst lining may come to lie immediately beneath the oral mucosa & fluctuation can be elicited.

RADIOLOGICAL FEATURES Radiographs reveal a unilocular radiolucency associated with crowns of unerupted impacted teeth; at times a multilocular effect can be seen when the cyst is of irregular shape due to bony trabeculations. Cysts have well-defined sclerotic margin unless when they are infected, then margins are poorly defined. With the pressure of an enlarging cyst, the unerupted tooth can be pushed away from its direction of eruption. Dentigerous cysts have a higher tendency to cause root resorption of adjacent teeth.

RADIOLOGICAL TYPES Radiologically, the dental follicle may expand around the unerupted or impacted tooth in three variations, i.e; 1.CIRCUMFERENTIAL: when the cystic cavity, radiographically ENCLOSE’S ENTIRE TOOTH 2.LATERAL: in this case, cystic cavity is located on ONE SIDE OF INVOLVED CROWN 3.CENTRAL / CORONAL: when cystic cavity, ENVELOPS THE CROWN OF IMPACTED TOOTH SYMMETRICALLY FROM ALL THE SIDES. This type of cyst may push the involved tooth away from its direction of eruption.

CYSTIC CONTENTS ASPIRATE Contains clear yellowish / straw colored fluid in which cholesterol crystals may be present & cystic contents have 5 gm % OR more of soluble protein. TREATMENT TREATMENT IS DECIDED BY THE SIZE OF THE CYST, ADEQUATE ACCESS, AND WHETHER IT IS DESIRABLE TO SAVE THE INVOLVED TOOTH. Aspiration of cyst & incisional biopsy MARSUPIALIZATION of larger cyst along with extraction of tooth. Decompression. Orthodontic treatment to allign the tooth.

MARSUPIALIZATION [ Partsch Surgery ] Indicated in children, if the cyst is very large in size & involved tooth / teeth are to be maintained. The tooth may erupt into occlusion as the defect heals with normal bone, or orthodontic forces may be used to bring the tooth into occlusion. ENUCLEATION The cyst can be enucleated together with the involved tooth in adults, as the possibility of tooth erupting is low. In children, an attempt could be made to save the tooth, in this case, the lining is separated from the neck of the tooth with a scalpel. This procedure is worth attempting, when root formation is complete, so that risk of tooth dislodgement is low.

LATERAL PERIODONTAL CYST A developmental cyst Lateral periodontal cysts are found lateral to the roots of vital teeth [erupted tooth] Types: Inflammatory Developmental CLINICAL FEATURES INCIDENCE; Cyst is usually found in adult males AGE; No specific age SITE; Occurs more often in mandible than in maxilla Commonly seen in mandibular cuspids, bicuspids & 3rd molar roots followed by anterior region of the maxilla The associated teeth are vital It never causes resorption of the root of the effected tooth

RADIOLOGICAL FEATURES Radiographs reveal a well-defined round or ovoid radiolucency with a sclerotic margin, the lamina dura of the involved tooth is destroyed. Most of the cysts are smaller than 1cm in size & are present between the cervical margin & apex of the root. “Teardrop-shaped” radiolucent area. In case of lower 3rd molar roots, they seem to be present in the bifurcation, bucally, or lingually or against the distal surface of the root. TREATMENT ENUCLEATION is generally method of choice, & is easily performed, because of the small size & easy access. All attempts should be made to avoid sacrificing the associated tooth.

CALCIFYING EPITHELIAL ODONTOGENIC CYST GORLIN CYST [ CEOC] WHO classifies it as benign tumor, but describes it as cyst. Un-common, slowly growing benign lesions Calcified tissues identified as dysplastic dentin, associated with odontoma. Location: 75% in bone, 25% in soft tissues related to jaws like gingiva & alveolar mucosa. Can be Intraosseous or Extraosseous lesion. Symptoms : slow growing, painless swelling.

CLINICAL FEATURES Incidence - 1% of odontogenic cysts Age – 2nd & 6th decade Site–Maxilla 70 %, [ more common, usually does not cross the midline, most common in maxillary premolar region ] Mandible-ANTERIOR REGION, sometimes crosses midline. Seen usually anterior to 1st molar region in mandible Most common in mandibular canine region Signs: cortical plate destruction, cystic mass become palpable Small lesions – Asymptomatic Large lesions Slowly enlarging bony hard swelling of jaw Displacement of regional teeth

RADIOLOGICAL FEATURES Unilocular / multilocular radiolucency Multiple small radio-opaque foci of varying density Resorption of roots of adjacent teeth Internal structure: Completely radiolucent with foci of calcification May be large solid masses Rarely multilocular Periphery & shape: Well defined corticated margins TREATMENT Enucleation & curettage

RADICULAR CYST An inflammatory cyst. Usually associated with a non-vital tooth. It may develop apically, when it is termed as a PERIAPICAL [PERIODONTAL] RADICULAR CYST. It may develop on the side of the root of a pulpless tooth, when it is termed as LATERAL [PERIODONTAL] RADICULAR CYST, this cyst should be differentiated from a DEVELOPMENTAL LATERAL PERIODONTAL CYST which is associated with a VITAL TOOTH. In a radicular cyst, if the involved tooth is exfoliated or extracted, and the cystic lesion remains within the bone, then it is known as RESIDUAL CYST.

Periapical (Radicular) Cyst - Developmental sequence Joseph A. Regezi. Oral Pathology: Clinical Pathologic Correlations, 4th Edition. Elsevier, 2002.

TREATMENT Nonvital teeth that are associated with the cyst, can either be extracted or restored and treated by endodontic treatment and apicoectomy. External sinus tracts should always be excised to prevent epithelial ingrowth. The commonly employed surgical procedure for radicular cyst is ENUCLEATION with PRIMARY CLOSURE Very small cysts can be removed through bony window or tooth socket. Large cysts that encroach upon the maxillary antrum or inferior alveolar neurovascular bundle or nose, may be preliminary treated by MARSUPIALIZATION.

RESIDUAL CYST Less inflammatory than radicular cyst A residual cyst is a cyst that remains after incomplete removal of the original cyst. The term residual is used most often for a radicular cyst that may be left behind most commonly after extraction of a tooth.