Periapical Granuloma

Etiology: the result of necrotic pulp tissue and by-products resulting from an inflammatory process that has damaged the tissue at the apex of the tooth. The infected tissue is the body’s defense mechanism coming into action. The periapical granuloma is the first stage of an inflammatory process caused by trauma, injury to the pulp through dental procedures, caries, periodontal disease that has affected the root area severely, or fractures to the tooth. All of these may contribute to the inflammatory process

Mode of transmission: N/A

Characteristics: The lesion cannot be distinguished from the radicular cyst discussed in the next section, since by all appearances, they are the same radiographically. The tooth may be asymptomatic, but in most cases, complaints such as sensitivity or pain do exist until the tooth becomes completely nonvital. The tooth will test nonvital in most cases, depending upon the degree of damage to the pulp. The dental granuloma is seen radiographically as a round or ovoid translucent lesion. The size of the lesion may vary from several millimeters to larger, more advanced lesions encompassing larger areas.

Implications: Vitality testing is crucial, since the tooth will test nonvital when obvious radiographic evidence is apparent. If the tooth is nonvital, endodontic treatment is needed.

Treatment: Extraction of the nonvital tooth or endodontic treatment is the usual procedure for granulomas. Apical curettage and apicoectomy may be performed. Antibiotic coverage may be needed to get the infection under control. The prognosis is good if all the granuloma is removed.

Radicular Cyst

Etiology: common causes are caries, trauma such as fracture or injury to the tooth, or periodontal disease.

Mode of transmission: None
Charactteristics: The radicular cyst may be found in any region of the mandible and maxilla, but it generally favors the maxillary anterior region at the apex of a nonvital tooth. The patient may experience no pain and is usually not aware of the cyst until it is diagnosed radiographically. The radiograph may show obvious evidence of root resorption. The radicular cyst appears as a well-circumscribed radiolucent lesion attached to a tooth root. In some cases, the cyst may appear lateral to the apex when a lateral pulp canal is involved.

Implications: Failure to remove the radicular cyst completely results in recurrence.

Treatment: Treatment usually involves several options: removal by extraction, surgery with curettage, and root canal therapy. Treatment may also include surgery and apicoectomy. Antibiotic coverage may be needed to get the infection under control. The prognosis is good with complete removal.

Aneurysmal Bone Cyst

Etiology: It is suggested that this type of bone cyst arises from prior trauma, and recent research suggests some genetic components. Cytogenetic research suggests chromosomal alterations.

Mode of transmission: N/A

Characteristics: The patient usually notices swelling with or without pain. The radiographic features of an aneurysmal bone cyst include a unilocular or multilocular lesion, described as having a “soap bubble” appearance. Thinning and expansion of the cortical bone may be seen. Ballooning and distention of the cortical bone is often recognized, and depending upon the stage of the cyst, the appearance will vary. The lesion presents as expansile, with thin peripheral bone that is blood filled, without the presence of what is called bruit (a purring sound at the suspected area of aneurysmal cyst), thrill (a vibration), or pulse pressure.

Implications: Aneurysmal bone cysts may cause the teeth to become displaced or loose because of bone expansion.

treatment: Excision and curettage are treatments of choice. When the lesion is removed completely, the prognosis is good. Cryotherapy, sclerotherapy, radionuclide ablation, and en bloc resection may be used for certain cases. There may be recurrence if any lesion remains, and the rate of this recurrence is usually very high.

Traumatic Bone Cyst (Simple Bone Cyst)

Etiology: thought to be caused by trauma

Mode of transmission: N/A

Characteristics: Increased swelling in the mouth may be observed, but pain is not usually a factor. The lesions are discovered on radiographs, with the patient reporting no pain or other symptoms. The radiographic appearance is that of a scalloping cyst with well-delineated radiolucent characteristics. Margins may be very sharp in some areas and ill defined in others. Root resorption, loss of lamina dura, cortical expansion, and cortical thinning are reported. The cyst is also often seen scalloping between the teeth.

Implications: The traumatic bone cyst may continue to expand and increase in size when not detected in the early stages. The lesion must be drained to begin healing.

Treatment: The usual treatment involves opening the cyst. Once the blood cavity is emptied, the bone will repair itself over time. The defect usually fills in from 6 months to 1 year. The recurrence rates range from 12 to 48%.

Periapical Cementoosseous Dysplasias

Etiology: The etiology of these lesions is unknown, but they are considered to be a dysplastic process affecting cells in the PDL and their ability to remodel bone and cementum.

Mode of transmission: N/A

Characteristics: The patient is usually asymptomatic, and the lesions are discovered on routine radiographs. Periapical COD occurs at the apex of vital teeth, with a propensity for the anterior mandibular teeth. The cementoma is asymptomatic and not usually noticed until seen on a radiograph.

Implications: The vitality of the tooth is important, since the tooth tests vital with periapical COD. Without the proper diagnostic procedure, the tooth may be treated with a root canal when this is not necessary.

Treatment: Periapical COD requires no treatment, and extraction or surgery is not required since the teeth remain vital. Early recognition and determination will alleviate unnecessary tests and surgery

Focal Cementoosseous Dysplasia

Focal COD is believed to be closely related to periapical COD, with most experts claiming that they are indeed variants of the same entity. Most cases occur in females around the fourth to sixth decade of life with a median age of 41 years. In contrast to the periapical COD, the focal COD occurs most often in whites rather than blacks. The lesion is described as a solitary, unilateral lesion that is well defined, with a thin radiolucent perimeter. The lesions can also be radiolucent, progressing in time to a more radiopaque, lesion.

Florid Cementoosseous Dysplasia

Florid COD mostly affects middle-aged adult black women (more than 90%) and Asian women and a familial tendency is reported. The disorder can affect any quadrant of the mouth. Found in both edentulous and dentulous areas and is sometimes seen in all quadrants at the same time. Clinically, there may be evidence of a yellow bone-like material, and during surgical removal, it is difficult to separate the material from the bone. The radiograph may have a more “ground-glass” type of appearance . The radiographic appearance of florid COD is one of progressing lucent and opaque quality, which is described as lobular. The differentiation between florid COD and simple bone cyst is not readily distinguishable, and in some cases, a bone cyst is reported when in actuality, it was a florid COD with secondary infections. The treatment is through observation, clinical recalls, and prophylaxis. Osteomyelitis can be a complication in severe cases.

Osteomyelitis: Acute and Chronic Forms

Etiology: A periapical abscess is most often the cause of the acute form of osteomyelitis. The chronic form may additionally be caused by a long-term inflammatory reaction from some stimulus, such as a systemic disease affecting the bone.

Mode of transmision: The acute form of osteomyelitis may have several infectious organisms involved in the disease process

Characteristics: Lymphadenopathy, fever, and pain are often symptoms of osteomyelitis and are especially noted in the acute form. An acute infection may not produce the destruction that the chronic form produces, because it has not been present long enough to create bone damage. In the chronic form, more evident patches of necrotic bone and diffuse radiolucent lesions are seen, and the lesions appear more mottled, with a sclerotic appearance on the radiograph.

Implications: The patient may have pain and lymphadenopathy. Addressing the cause of the osteomyelitis is paramount. The correct antibiotic is needed to treat the infection; therefore, identification of the specific organism through laboratory tests is crucial.

Treatment: Drainage and antibiotics are needed to treat the acute form of osteomyelitis. The chronic form is more difficult to manage because of necrosis. Surgery is indicated, with antibiotic coverage. In acute osteomyelitis, antibiotics are very effective, but chronic osteomyelitis usually requires surgery, antibiotics, and drainage.

Lateral Periodontal Cyst (Botryoid Odontogenic Cyst)

Etiology: believed to develop from the dental lamina remnants from within the bone

Mode of transmission: N/A

Characteristics: The lateral periodontal cyst is asymptomatic in most cases and is not usually noticed until seen on a radiograph. The cyst is usually unilocular, is round or oval, and is well delineated. The teeth associated with the lateral periodontal cyst are vital. When a multilocular cyst is present, it is called a variant of the lateral periodontal cyst and is known as the botryoid odontogenic cyst. These cysts have a grape-like appearance.

Implications: The cyst should be identified as a lateral periodontal cyst, since it is necessary to rule out an inflammatory-type lesion or a more serious type of cyst or tumor, such as the odontogenic keratocyst (OKC)

Treatment: Surgical excision and pathologic review are treatments of choice. Vitality testing is important in order to avoid unnecessary endodontic treatment. There may be a higher rate of recurrence when the cyst is a botryoid odontogenic cyst. Periodic radiographic follow-up is needed. The prognosis is excellent.

Gingival Cyst of the Adult

The gingival cyst of the adult is the uncommon soft tissue counterpart to the lateral periodontal cyst. Both the gingival and the lateral periodontal cyst are developmental cysts. it is thought that misdiagnosis may occur and the lesion may be diagnosed as a mucocele because of the similar appearance clinically; however, mucoceles do not occur on the gingiva. The gingival cyst of the adult is located on the facial gingiva or alveolar mucosa. The gingival cyst may occur at a later age, around the fourth through sixth decade of life, occurring predominately in the premolar and canine mandible region 60% of the time, with a slight female predilection. The cyst presents as a firm, flesh-colored nodule that is painless, is nonmobile, and usually measures 1 to 3 mm in diameter, although some may be larger. The teeth in the area test vital unless previous damage from other sources has occurred that damage the pulp. Treatment consists of surgical excision and histopathologic examination. Alveolar defects may be noted upon removal of the growth that may not be evident initially in a radiograph

Dentigerous Cyst

Etiology: Dentigerous cysts are odontogenic in development. The dentigerous cysts arise from a cystic change in the dental follicle following crown formation when the follicle separates from the crown of the tooth. The reduced enamel epithelium forms from the original ameloblasts of the enamel organ.

Mode of transmission: N/A

Characteristics: The dentigerous cyst is usually only evident on radiographs, with no symptoms of pain or discomfort reported. On radiographs, it is well circumscribed, unilocular, and sometimes multilocular. On radiograph, the dentigerous cyst is well circumscribed, unilocular, and sometimes multilocular. Since there is no calcified material, the cyst appears completely radiolucent.

Implications: Delayed tooth eruption is a common theme. The dentigerous cyst can become quite large and has the potential to displace teeth and resorb roots. Dentigerous cysts continue to grow and expand; therefore, early diagnosis is imperative.

Treatment: Complete removal of the cyst is indicated, since the recurrence is high when this is not fully accomplished.

Eruption Cyst

Etiology: The eruption cyst, sometimes called an eruption hematoma, is considered a variant of the dentigerous cyst and is caused by the accumulation of fluid or blood between the crown of an erupting tooth and the reduced enamel organ, due to trauma.

Mode of transmission: N/A

Characteristics: The tissue of the eruption cyst may have a darker appearance and appear elevated. The eruption cyst is seen as a smooth bluish swelling (dome-like) on the crest of the alveolar ridge. The radiographic finding of an eruption cyst is an enlarged follicular space. The cysts may have a bluish cast due to the inflammatory inner core and blood accumulation.

Implications: The only dental implication is the failure of the tooth to erupt; therefore, the cyst may be opened to hasten the event. Most eruption cysts are left to dissipate on their own.

Treatment: No treatment is necessary; however, on occasion, removal of the overlying tissue could facilitate a quicker eruption. The tooth eventually erupts through the tissue, and the cyst disappears.

Odontogenic Keratocyst

Etiology: develops from the dental lamina or its remnants.

Mode of transmission: N/A

Characteristics: OKCs occur most often in the posterior mandibular region and can occupy most of the ramus in some cases. In late stages of development, the cyst may become large enough to displace teeth and extend through the cancellous bone into the oral cavity. As the jaw becomes weakened, a fracture is more likely to occur. Radiographically, the lesions can be multilocular or unilocular, well circumscribed on the radiograph, and radiolucent, with a scalloped appearance. The radiographic appearance closely resembles that of an ameloblastoma in certain cases. They can also be round and ovoid and appear laterally to the tooth, making them appear as a lateral periodontal cyst

Implications: Although the OKC can radiographically resemble other cysts, the microscopic interpretation is unique once a specimen is submitted. The association with nevoid BCC syndrome is especially important in a diagnosis, and the cysts have very aggressive behavior. Therefore, prompt treatment is required. Multiple OKCs should alert the practitioner to the possibility of nevoid basal cell carcinoma

Treatment: Since recurrence is high, but varied (from 5 to 62%), careful removal of the entire cyst is crucial, and the capsule must be removed intact so that daughter cells do not remain. Many OKCs today are treated by decompression (marsupialization), allowing the cyst to shrink before definitive surgical removal. The thin wall is often difficult to separate from bone and remove in one piece, often allowing daughter cells to remain and increase in occurrence.

Nevoid Basal Cell Carcinoma Syndrome

nevoid basal cell carcinoma syndrome is a prime concern for patients diagnosed with OKC due to a close association between the two disorders. This syndrome is an inherited autosomal dominant disorder with a male predilection of 3 to 1. The syndrome has five main components: basal cell carcinoma (10 or more), jaw cysts, congenital skeletal anomalies (bifid fused rib or vertebrae, ectopic), calcifications, and palmar and plantar pits. Additionally, there are other reported characteristics associated with this disease including a wide nasal bridge and frontal bossing, milia, potential for mental retardation, ovarian fibromas, and increased incidence of cleft lip and palate.

Calcifying Odontogenic Cyst: COC

Etiology: believed to be derived from the reduced enamel epithelium or odontogenic epithelium.

Mode of transmission: N/A

Characteristics: COCs may be found as masses within the oral tissues, almost always within the gingiva. When they do occur, they may resemble a gingival cyst or a peripheral giant cell granuloma. These cysts can occur in any location and present as an expansile intraosseous lesion or tender gingival swelling. Radiographically, the COCs are unilocular or multilocular radiolucencies that exhibit clearly defined margins. Mixtures of calcifications and radiolucent properties are usually seen on the radiograph.

Implications: Definitive diagnosis is important to rule out more aggressive lesions, and complete removal is necessary.

Treatment: Surgical excision is recommended for the COC.

Globulomaxillary Cyst
Etiology: believed to represent a fissural cyst that arose from the epithelium that was thought to be trapped when the globular portion of the median nasal process fused with the maxillary process, but has essentially been deemed by some oral pathologists as unlikely and deleted from WHO list in 2017.

Mode of transmission: N/A

Characteristics: The cyst may be an inverted pear-shaped lesion because of the location, causing divergence of the tooth roots. It is circumscribed and radiolucent. Vitality of the pulp provides some evidence about the type of cyst.
A classic radiographic characteristic of the cyst is the divergence of the roots when the lesion is large enough to cause this factor.

Implications: The vitality of the teeth involved, such as the lateral and cuspid, must be evaluated. Endodontic therapy should be administered when necessary.

Treatment: Surgical removal is the treatment of choice, and the prognosis is good, depending upon the type of cyst. Recurrence is rare. Any resemblance to the OKC should be evaluated frequently because of the higher recurrence rate involved with these cysts. Treatment will depend upon the microscopic evaluation of the lesion.

Glandular Odontogenic Cyst

Etiology: derived from odontogenic origins

Mode of transmission: N/A

Characteristics: Both swelling and expansion may be noted. Some cases are asymptomatic. Some reports of pain/discomfort, infection, and paresthesia have also been reported. The most distinguishing characteristics are those that differentiate the GOC from other cyst structures. The mucoepidermoid carcinoma may be considered because of a shared histology with the GOC and with other entities such as the dentigerous cyst that may display some metaplastic changes.

Implications: Follow-up is important since the recurrence rate is very high. Radiographic examinations are important in an early diagnosis of recurrence.

Treatment: Most cases are treated conservatively with enucleation, curettage, cystectomy, and excision. There is a recurrence rate of 50% when these lesions are treated conservatively through curettage, enucleation, and partial osteotomy.

Nasopalatine Duct Cyst

Etiology: This cyst arises from epithelial remnants of the embryologic structure of the nasopalatine ducts, and the structure connects the oral and nasal cavities in the area of the incisive canal, probably because of infection or some stimulation.

Mode of transmission: N/A

Characteristics: The patient may complain of pain, tenderness, and swelling, and drainage may be noted in the maxillary incisor region. Radiographically, the nasopalatine cyst is seen between the maxillary central incisors. The lesion is a well-circumscribed radiolucent lesion, which may have a sclerotic border.

Implications: The cyst is not radiographically diagnostic and must be removed and biopsied for definitive microscopic evaluation.

Treatment: Complete surgical removal is needed

Median Palatine Cyst

The median palatine cyst (MPC) is located in the same vicinity as the nasopalatine cyst but is more apically centered toward the midline of the hard palate. The lesion is lined by stratified squamous epithelium and is surrounded by dense connective tissue. The MPC is classified as a rare fissural cyst and is believed to develop from entrapped epithelium along the embryonic line of fusion in the two lateral maxillary processes that fuse to make the hard palate. There is controversy around this entity. The patient may complain of pain and expansion of the palate when the cyst impinges the nasopalatine nerve. There is a reported male predilection of 4:1 with an age range of 13 to 52 years.

Static Bone Cyst

Etiology: The static bone cyst is not a true cyst, although by all appearances on a radiograph, it resembles a cyst. Technically, the static bone cyst is a defect in the mandible that surrounds salivary gland tissue. It is believed to be entrapment of the salivary gland tissue and is not lined by epithelium

Mode of transmission: N/A

Characteristics: The static bone cyst is asymptomatic and is usually discovered when a Panorex film is taken. On a radiograph, the bone cyst is seen as a radiolucency in the posterior mandible below the mandibular canal. The static bone cyst is a sharply circumscribed, oval, radiolucent lesion with a sclerotic border. CBCT images are useful as they can usually demonstrate the lingual cortical defect and show that the lesion is not intrabony.

Implications: The static bone cyst is usually diagnosed clinically by using radiographs; however, when the location is superior to the mandibular canal, a biopsy may be needed to rule out pathology.

Treatment: The static bone cyst is noted and followed long term, and if any changes occur, they are noted in the patient’s record. Other cysts should be considered if the cyst is occurring above the mandibular canal.

Adenomatoid Odontogenic Tumor

Etiology: Once thought to be a variant of the ameloblastoma, the adenomatoid odontogenic tumor (AOT) is now classified as an encapsulated benign epithelial odontogenic tumor.

Mode of transmission: NA

Characteristics: Swelling in the facial area is sometimes reported, causing flaring of the nasolabial fold and extending beyond the facial contour. As the tumor expands and increases in size, there may be root displacement and a bony hard expansion with an eggshell cracking appearance over the protrusion.For the most part, this tumor appears radiolucent on radiograph but may exhibit small opaque foci within the tumor. The number and size of the foci determine the radiographic appearance of the lesion.

Implications: Facial asymmetry is one of the first signs to be noticed by the patient as the tumor increases in size. The tumor expands and should be excised

Treatment: Complete removal of the tumor is necessary, and the prognosis is excellent without any recurrence

Odontogenic Myxoma

Etiology: derived from odontogenic ectomesenchyme

Mode of transmission: NA

Characteristics: Radiographically, the tumors can be unilocular or multilocular, and the radiolucencies may have a scalloped appearance. Myxomas have also been described as having a “step ladder” or “honeycombed” appearance. The margins may be well defined or they may be diffuse.

Implications: Enlarged dental follicles or the dental papilla of a developing tooth may be mistaken for the myxomas upon microscopic examination. They also can be confused with other myxoid jaw neoplasms. The tumors can become quite large, causing tooth displacement.

Treatment:: The myxoma is removed surgically, usually with a wide margin of normal bone. The highly gelatinous material makes removal difficult with curettage, and the recurrence rate is as high as 25% because the tumor is nonencapsulated. Fragments are difficult to remove.

Ameloblastic Fibroma

Etiology: believed to originate from odontogenic ectomesenchyme and odontogenic epithelium. It is a nonencapsulated tumor resembling dental papillae and small islands of odontogenic epithelium resembling dental lamina

Mode of transmission: NA

Characteristics: The patient usually experiences no pain with any swelling that may occur. The ameloblastic fibroma has potential for extensive growth causing jaw expansion. Occasionally, there may be calcified material containing enamel and dentin. If so, the lesion is identified as an ameloblastic fibroodontoma and classified as an odontoma. Radiographically, the lesion can be unilocular or multilocular. It is normally well defined and usually associated with an unerupted tooth.

Implications: Generally, the ameloblastic fibroma is asymptomatic.

Treatment: Conservative excision is the treatment of choice. Recurrence is seen in approximately 20% of cases. Some recur as ameloblastic fibrosarcomas, which have been reported in previously benign cases of ameloblastic fibromas.

Langerhans Cell Disease: Langerhans Cell Histiocytosis

Etiology: The basic cause of Langerhans cell disease, formally called histiocytosis X, is unknown. It involves proliferation of the Langerhans cells, which normally reside in the epidermis, bone marrow, lymph nodes, and mucosa. Langerhans cells are a specialized histiocyte involved in antigen processing for our immune system. They have unique Birbeck granules in their cytoplasm ultrastructurally. The Langerhans are usually mixed with eosinophils histologically. In some cases, a neoplastic transformation is believed responsible for this disease. An immune response has also been implicated. Additionally, a neoplastic process and a reactive process have been suggested as causal.

Mode of transmission: NA

Characteristics: Poor healing is common with Langerhans cell disease, dermatologic conditions may be evident, and all bones of the body may be affected. Lymphadenopathy may be present, cranial bones may be involved, and the cutaneous areas may involve rashes and erythematic lesions. Radiographically, the bone lesions resemble a “punched-out” appearance with sharply demarcated lesions. Lesions commonly present as a “floating tooth/teeth.” The disease may involve one or more multiple bones in the body, including the bones around the teeth, contributing to loosening (called “floating teeth”). Tenderness, pain, and swelling are common complaints. The patients may overlap in the above stated symptoms and may or may not exhibit the stated characteristic symptoms, depending upon the stage and type of the disorder.

Implications: Lesions that occur periapically can be confused with periapical cyst or granulomas. Tooth vitality would still be present.

Treatment: The treatment depends upon the involvement of the disease and the age of the patient. Conservative surgical treatment is sometimes the only treatment. However, in more extensive disease involvement, chemotherapy may be needed as well. Additionally, bone marrow transplantation may be done; but essentially, the more widespread the lesions, the poorer the prognosis. The prognosis is more favorable when the disease states develop in older young adults.