Odontogenic cysts

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.

1. Odontogenic Cysts Dr. Amin Abusallamah

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

3. 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.

4. 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

5. 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.

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 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

9. 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.

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

11. Clinical features Frequency: It is most common cystic lesion of jaw comprising  about approximately 52% of jaw cystic lesions. Age: found in 4 th  & 5 th  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.

12. 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.

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 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.

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

15. Residual cyst

16. 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.

17. Histopathology Same 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 well corticated. It can cause bone expansion and displacement of the adjacent teeth.

19. Radiographic features 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.

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

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

22. Dentigerous cyst

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

24. 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.

25. 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.

26. 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.

27. 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.

28. Radiographic features 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 ).

29. Differential Diagnosis 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.

30. Differential Diagnosis 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.

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

32. Lateral periodontal cyst

33. 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 ).

34. 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.

35. 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

36. Radiographic features 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

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 multilocular appearance may resemble a small ameloblastoma .

38. Treatment Enucleation with preservation of adjoining teeth

39. Odontogenic keratocyst

40. 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

41. 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.

42. 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.

43. 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.

44. Radiographic features 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.

45. Radiographic features 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.

46. Radiographic features 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

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 minimal bone expansion. several OKCs are found, these cysts may constitute part of a basal cell nevus syndrome.

48. 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.

49. Calcifying odontogenic cyst ( Gorlin cyst)

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

51. 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.

52. 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 .

53. 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.

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 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.

56. Differential Diagnosis Dentigerous cyst, OKC , Ameloblastoma . In later stages , Adenomatoid odontogenic tumor, Ameloblastic fibroodontoma

57. Treatment Surgical Enucleation is the preferred therapy

58. Principle of Treatment local anesthesia. Types of Flaps. Surgical removal the of the cyst .

59. Local anesthesia

60. 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

61. 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 .

62. 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

63. 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.

64. 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 .

65. Surgical removal the of the cyst The surgical procedure for treatment of a cyst with enucleation includes the following steps : Reflection of a mucoperiosteal flap . Removal of bone and exposure of part of the cyst . Enucleation of the cystic sac. Care of the wound and suturing.

66. Surgical removal the of the cyst Panoramic radiograph showing an extensive radicularlesion at the region of teeth 22, 23, 24 Clinical photograph of case

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

70. Surgical removal the of the cyst Operation 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 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

72. Surgical removal the of the cyst 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.

73. Surgical removal the of the cyst 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

74. Surgical removal the of the cyst Exposure of cyst after removal of bone Suturing of wound margins with cystic wall

75. Surgical removal the of the cyst Packing of cystic cavity with iodoform gauz Cystic cavity after insertion of gauze

76. Thank you