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Odontogenic cysts

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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 …

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. 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. 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.


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  • 1. Odontogenic CystsDr. Amin Abusallamah
  • 2. Outline1. INTRODUCTION2. CLASSIFICATION3. CAUSES4. HISTOPATHOLOGY5. CLICAL FEATURES6. RADIOGRAPHIC FEATURES7. DIFFERENTIAL DIAGNOSIS8. TREATMENT9. PRINCIPLE OF TREATMENTA. Types of Flaps.B. Surgical removal the of the cyst .
  • 3. INTRODUCTION• A cyst is an epithelium-lined saccontaining fluid or semisolid material.In the formation of a cyst, the epithelialcells first proliferate and later undergodegeneration and liquefaction. Theliquefied material exerts equal pressureon the walls of the cyst from within.
  • 4. INTRODUCTION• Cysts grow by expansion and thusdisplace the adjacent teeth by pressure.May can produce expansion of thecortical bone. On a radiograph, theradiolucency of a cyst is usuallybordered by a radiopaque periphery ofdense sclerotic bone. The radiolucencymay be unilocular or multilocular
  • 5. INTRODUCTION• Odontogenic cysts are those whicharise from the epithelium associatedwith the development of teeth. Thesource of epithelium is from theenamel organ, the reduced enamelepithelium, the cell rests of Malassez orthe remnants of the dental lamina.
  • 6. CLASSIFICATION• Radicular cyst• Residual cyst• Dentigerous cyst (follicular)• Primordial cyst• Lateral periodontal cyst• Odontogenic keratocyst• Calcifying odontogenic cyst (Gorlin cyst)
  • 7. Radicular cyst
  • 8. Causes• A periapical cyst develops from a preexistingperiapical granuloma, which is a focus of chronicallyinflamed granulation tissue in bone located at theapex of a nonvital tooth.• Periapical granulomas are initiated and maintainedby the degradation products of necrotic pulp tissue
  • 9. Histopathology• The periapical cyst is lined by nonkeratinized stratified squamousepithelium of variable.Transmigration of inflammatorycells through the epithelium iscommon, with large numbers of(PMNs) and fewer numbers oflymphocytes involved.
  • 10. Histopathology• The underlying supportiveconnective tissue may befocally or diffusely infiltratedwith a mixed inflammatorycell population.
  • 11. Clinical features• Frequency:It is most common cystic lesion of jawcomprising 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 maxillaryanterior region. Most commonly at apices of teeth.
  • 12. Radiographic features• Location: In most cases the epicenter of a radicular cyst islocated approximately at the apex of a nonvital tooth.• Periphery and shape: The periphery usually has a welldefined 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 islarge, displacement and resorption of the roots of adjacentteeth.
  • 13. 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 greaterthan 2 cm in diameter are more characteristic of a cyst.• Early stage of periapical cemental dysplasia. tooth are vital.• Apical scar.• Periapical surgical defect.
  • 14. TreatmentEnucleation with preservation of tooth and RCTwith follow-upOrExtraction with curettage
  • 15. Residual cyst
  • 16. Causes• When the necrotic tooth is extracted but the cyst lining isincompletely removed, a residual cyst may from months toyears after the develop initial extirpation If either or the aresidual cyst original periapical cyst remainsuntreated, continued growth can cause significant boneresorption and weakening of the mandible or maxilla.
  • 17. HistopathologySame like Radicular or periapical cyst
  • 18. 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 wellcorticated.• It can cause bone expansion and displacement of the adjacentteeth.
  • 19. Radiographic features• Location: In both jaw but more in the mandible. Found atperiapical location, in place of an extracted tooth.• Periphery and shape: The periphery usually has a well definedcortical border.• Internal structure: In most cases the internal structure ofradicular cysts is radiolucent.• Effects on surrounding structures: large cyst , displacementand resorption of the roots of adjacent teeth may occur.
  • 20. Differential Diagnosis• Keratocyst: residual cyst has greater potential forexpansion compared with a keratocyst.• Stafne developmental salivary gland defect is locatedbelow the mandibular canal
  • 21. TreatmentEnucleation if the lesion is smallOrMarsupialization if the lesion is large
  • 22. Dentigerous cyst
  • 23. Causes• Dentigerous cyst develops from proliferation of theenamel organ remnant or reduced enamelepithelium.
  • 24. Histopathology• The supporting fibrous connectivetissue wall of the cyst is lined bystratified squamous epithelium.In an uninflamed dentigerous cystthe epithelial lining isnonkeratinized and tends to beapproximately four to six celllayers thick.
  • 25. Histopathology• On occasion, numerous mucouscells, ciliated cells, andrarely, sebaceous cells may be foundin the lining of the epithelium. Theepithelium-connective tissuejunction is generally flat, although incases in which there is secondaryinflammation, epithelial byperplasiamay be noted.
  • 26. Clinical features• Dentigerous cysts are most commonlyseen in association with third molarsand maxillary canines, which are themost commonly impacted teeth. Thehighest incidence of dentigerous cystsoccurs during the second and thirddecades. There is a greater incidence inmales, with a ratio of 1.6 to 1 reported.
  • 27. Clinical features• Symptoms are generally absent, withdelayed eruption being the mostcommon indication of dentigerous cystformation. This cyst is capable ofachieving significant size, occasionallywith associated cortical bone expansionbut rarely to a size that predisposes thepatient to a pathologic fracture.
  • 28. Radiographic features• Location: most common sites are mandibular third molar, maxillarycanine, maxillary third molar. Associated with the crown of an un-erupted and displaced tooth.• Periphery and shape: The periphery usually has a well definedcortical border. Attached to the CEJ.• Internal structure: most cases is radiolucent surrounding the crown.• Effects on surrounding structures: Large cysts tend to expand theouter plate (usually buccally).
  • 29. Differential Diagnosis• Hyperplastic follicle The size of the normal follicular space is 2to 3 mm. If the follicular space exceeds 5 mm, a dentigerouscyst is more likely.• Odontogenic keratocyst ,does not expand the bone to thesame degree as a dentigerous cyst, is less likely to resorbteeth, and may attach farther apically on the root instead of atthe cementoenamel junction.
  • 30. Differential Diagnosis• Ameloblastjc fibroma• Cystic ameloblastoma The internal structure in both of themdifferentiate• Adenomatoid odontogenic tumors• Calcified odontogenic cysts Both can surround the crown androot of the involved tooth. Evidence of a radiopaque internalstructure should be sought in these two lesions.
  • 31. TreatmentMarsupialization is stronglyrecommended when tooth oradjacent teeth prevented from asorEnucleation is an alternative treatmentwith removal of tooth
  • 32. Lateral periodontalcyst
  • 33. Causes• The origin of this cyst is believed to be related to proliferationof rests of dental lamina.• The lateral periodontal cyst has been pathogcnetically linkedto the gingival cyst of the adult; t the former is believed toarise from dental lamina remnants within bone, and the latterfrom dental lamina remnants in soft tissue between the oralepithelium and the periosteum (rests of Serres).
  • 34. Histopathology• The close relationship between the twoentities is further supported by theirsimilar distribution in sites containing ahigher concentration of dental laminarests, and their identical histology. Bycontrast, periapical cysts are mostcommon at the apices of teeth, whererests of Malassez are more plentiful.
  • 35. Clinical features• Age : Adults• Location : Lateral periodontal membrane especiallymandibular , cuspid and premolar area• Usually asypmtomatic ; associated tooth is vital ;origin fromrests of dental lamina ;• some keratocysts are found in a lateral root position;gingival cyst be soft tissue of adult may counterpart
  • 36. Radiographic features• Location: 50-75% of lateral periodontal cysts develop in themandible, mostly in a region extending from the lateral incisorto the second premolar.• Periphery and shape: well-defined radiolucency with aprominent cortical boundary and a round or oval shape.• Internal structure: usually is radiolucent.• Effects on surrounding structures: Large cysts can displaceadjacent teeth and cause expansion
  • 37. Differential Diagnosis• Small OKC• Mental foramen• Small neurofibroma• Radicular cyst at the foramen of an accessory pulp canal.• The multiple (botryoid) cysts with a multilocularappearance may resemble a small ameloblastoma.
  • 38. TreatmentEnucleation with preservation ofadjoining teeth
  • 39. Odontogenickeratocyst
  • 40. Causes• There is general agreement that OKCs develop from dentallamina remnants in the mandible and maxilla. However, anorigin of this cyst From extension of basal cells of theoverlying oral epithelium has also been suggested.• Genetic
  • 41. Histopathology• The epithelial lining is uniformly thin, generally ranging from 8to 10 cell layers thick.• The basal layer exhibits a characteristic palisaded pattern withpolarized and intensely stained nuclei of uniform diameter.The luminal epithelial cells are parakeratinized and produce anuneven or corrugated profile.
  • 42. Histopathology• Additional histologic features that mayoccasionally be encountered includebudding of the basal cells into the C.Twall and microcyst formation.• The fibrous connective tissuecomponent of the cyst wall is often freeof inflammatory cell infiltrate and isrelatively thin.
  • 43. Clinical features• Age: Any age , especially adults• Location : Mandibular molar ramus area favored ; may befound dentigerous , in position of lateral root , periapical , orprimordial cyst• OKCs are relatively common jaw cysts They occur at any ageand have a peak incidence within the second and thirddecades.
  • 44. Radiographic features• Location : The most common is the posterior body of themandible (90% posterior to the canines)and ramus (morethan 50%). This type of cyst occasionally has the samepericoronal position asdentigerous cyst.• Periphery and shape Usually : with a cortical border unlessbecome secondarily infected. The cyst may have a smooth(round or oval shape), or it may have a scalloped outline.
  • 45. Radiographic features• Internal structure• most commonly is radiolucent.• The cystic cavity contain keratin.• In some cases curved internal septa may be present, givingthe lesion a multilocular Appearance.
  • 46. Radiographic features• The effects on surrounding structures : It grow along theinternal aspect of the jaws, causing minimal expansion exceptfor the upper ramus and coronoid process, whereconsiderable expansion may occur. OKCs can displace andresorbe teeth but to a slightly lesser degree than dentigerouscysts. The inferior alveolar nerve canal may be displacedinferiorly. In the maxilla this cyst can invaginate and occupythe entire maxillary antrum
  • 47. Differential Diagnosis• 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 minimalbone expansion.• several OKCs are found, these cysts may constitute part of abasal cell nevus syndrome.
  • 48. TreatmentWide (local) surgical excision for prevent therecurrenceorMarsupialization - the surgical opening of the(KCOT) cavity and a creation of a marsupial-like pouch, so that the cavity is in contact withthe outside for an extended period.
  • 49. Calcifyingodontogenic cyst(Gorlin cyst)
  • 50. Causes• COGs are believed to be derived from odontogenic epithelialremnants within the gingiva or within the mandible or maxilla.
  • 51. Histopathology• Most COCs present as well-delineated cystic proliferations witha fibrous connective tissue wall linedby odontogenic epithelium.Intraluminal epithelial proliferationoccasionally obscures the cystlumen, thereby producing theimpression of a solid tumor.
  • 52. Histopathology• The basal epithelium may focally be quite prominent, withhyperchromatic nuclei and a cuboidal to columnar pattern.Above the basal layer are more loosely arranged epithelialcells, sometimes resembling the stellate reticulum of theenamel organ. The most prominent and unique microscopicfeature is the presence of ghost cell keratinization.
  • 53. Histopathology• The ghost cells are anucleate andretain the outline of thecell membrane. These cellsundergo dystrophic mineralizationcharacterized by fine basophilicgranularity, which may eventuallyresult in large sheets of calcinedmaterial On occasion.
  • 54. Clinical features• Age: Any age• Location : Maxilla favored ; gingiva second most common site• No distinctive age gender, gender, or locationLucent to mixed radiographic patterns
  • 55. Radiographic features• COCs may present as unilocular or multilocular radiolucencieswith discrete, welldemarcated margins. Within theradiolucency there may be scattered, irregularly sizedcalcifications. Such opacities may produce a salt-and-peppertype of pattern, with an equal and diffuse distribution. Insome cases mineralization may develop to such an extent thatthe radiographic margins of the lesion are difficult todetermine.
  • 56. Differential Diagnosis• Dentigerous cyst,• OKC,• Ameloblastoma. In later stages ,• Adenomatoid odontogenic tumor,• Ameloblastic fibroodontoma
  • 57. TreatmentSurgical Enucleation is the preferredtherapy
  • 58. Principle of Treatment1. local anesthesia.2. Types of Flaps.3. Surgical removal the of the cyst .
  • 59. Local anesthesia
  • 60. Types of Flaps1. Trapezoidal flap.• Advantage : Provides excellentaccess, allows surgery to be performedon more than two teeth, produces notension in the tissues allows easyreapproximation of the flap to its originalposition.• Disadvantages: Produces a defect in theattachedgingiva
  • 61. Types of Flaps2. Triangular Flap.• Advantage : Ensures an adequate bloodsupply, satisfactory visualization, verygood stability .• Disadvantages: Limited access to longroots, tension is created when the flap isheld with a retractor, and it causes adefect in the attached gingiva.
  • 62. Types of Flaps3. Envelope Flap.• Advantage : Avoidance of verticalincision and easy reapproximation tooriginal position• Disadvantages: Difficult reflection(mainly palatally), great tension with a riskof the ends tearing, limited visualizationin apicoectomies, limitedaccess, possibility of injury of palatalvessels and nerves, defect of attachedgingiva
  • 63. Types of Flaps4. Semilunar Flap.• Advantage : Small incision and easyreflection, no recession of gingivaearound the prosthetic restoration.• Disadvantages: The incision beingperformed right over the bone lesion due tomiscalculation, scarring in the anteriorarea, difficulty of reapproximation , limitedaccess and visualization, tendency to tear.
  • 64. Surgical removal the of the cyst• Enucleation: This technique involves complete removal ofthe cystic sac and healing of the wound by primary intention.This is the most satisfactory method of treatment of a cystand is indicated in all cases where cysts are involved, whosewall may be removed without damaging adjacent teeth andother anatomic structures.
  • 65. Surgical removal the of the cyst• The surgical procedure for treatment of a cyst withenucleation 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.
  • 66. Surgical removal the of the cystPanoramic radiograph showing anextensive radicularlesion at the regionof teeth 22, 23, 24Clinical photograph of case
  • 67. Surgical removal the of the cystRemoval of maxillary cyst, with labial access. Incision for creating a trapezoidal flap.Reflection of flap and exposure of surgical field.
  • 68. Surgical removal the of the cystRemoval of bone at the labial aspect respective to the lesion.Osseous window created to expose part of the lesion.
  • 69. Surgical removal the of the cystRemoval of cyst from bony cavity, using hemostat and curette.Surgical field after removal of lesion.
  • 70. Surgical removal the of the cystOperation site after placement of sutures.Panoramic radiograph and clinical photograph taken 2 months after the surgical procedure.
  • 71. Surgical removal the of the cyst• Marsupialization This method is usually employed for theremoval of large cysts and entails opening a surgical windowat an appropriate site above the lesion. In order to create thesurgical window, initially a circular incision is made, whichincludes the mucoperiosteum, the underlying perforated(usually) bone, and the respective wall of the cystic sac
  • 72. Surgical removal the of the cyst• Marsupialization: After this procedure, the contents of the cystare evacuated, and interrupted sutures are placed around theperiphery of the cyst, suturing the mucoperiosteum and the cysticwall together . Afterwards, the cystic cavity is irrigated with salinesolution and packed with iodoform gauze ,which is removed a weeklater together with the sutures. During that period, the woundmargins will have healed, establishing permanent communication.Irrigation of the cystic cavity is performed several timesdaily, keeping it clean of food debris and avertinga potentialinfection.
  • 73. Surgical removal the of the cystMarsupialization method. Circular incision includes mucosa and periosteum.Exposure of buccal cortical plate and removal of portion of bone with round burEnlargementof osseouswindow withrongeur
  • 74. Surgical removal the of the cystExposure of cystafter removal ofboneSuturing of woundmargins withcystic wall
  • 75. Surgical removal the of the cystPacking of cysticcavity withiodoform gauzCystic cavity afterinsertion ofgauze
  • 76. Thankyou