Cysts derived from the tissues involved in odontogenesis.

Represents 1/3 of all odontogenic cysts.

Associated with the crown of an impacted or unerupted permanent tooth and rarely involves an unerupted deciduous tooth.

Caused by an accumulation of fluid between the reduced enamel epithelium and the crown of the tooth.

Can cause bony expansion, root displacement, and root resorption.

Well-delineated unilocular or multilocular radiolucency.

Root resorption may be evident.

Impacted tooth may be displaced a long distance from its original site.

Size and location of the cyst will dictate treatment.

Small lesions – enucleation.

Larger lesions – marsupialization (followed by enucleation after decompression).

Recurrence is uncommon.

All ages, and all teeth, can be affected.

Most common cyst of the jaw bones.

Occurs most commonly in the maxilla.

Forms as a sequela of chronic inflammation in a preexisting periapical granuloma.

Cyst is usually located at the apex of a non-vital tooth.

Well-circumscribed unilocular radiolucency around the apex.

May cause root resorption or tooth displacement.

Endodontic therapy.

Extraction of tooth with apical curettage/enucleation.

Endodontic therapy with apicoectomy.

All ages.

Cyst that has been left in the jaw bone after the associated tooth has been extracted.

More common in maxilla.

Well-defined radiolucency.

Simple excision .

Also has a polycystic variant known as the botryoid odontogenic cyst (appears in a grapelike cluster).

Most common in second–fourth decades.

Arises in the periodontal ligament along the lateral aspect of the root of a tooth.

Teeth are vital.

Intrabony counterpart of the gingival cyst of adults.

More common in males.

Mandible: Canine-premolar region.

Maxilla: Lateral incisor-canine region.

Asymptomatic.

Well-defined (unilocular or multilocular) radiolucency along the lateral surface of tooth root.

Multilocular appearance seen in botryoid variant.

Enucleation

Large variation in the age of presentation, second to eighth decades of life (average fifth decade).

Rare cyst that can show clinically aggressive behavior (expansion, pain, and paresthesia).

Has a strong predilection for the anterior mandible and usually crosses the midline.

Can have histological features of a low-grade mucoepidermoid carcinoma.

Unilocular or multilocular well-defined radiolucency surrounded by a sclerotic border.

Larger cysts may cause bony expansion and cortical disruption.

Curettage.

Some surgeons advocate for marginal or en bloc resection due to high recurrence (30%) [1].

Most commonly in second–third decade.

Associated with the PTCH tumor suppressor gene.

Derived from the rests of dental lamina (rests of Serres).

Slight male predilection.

More common in the mandible – third molar/ramus area.

Maxilla: posterior region is the most common area for occurrence.

Aggressive growth potential with higher tendency to recur (most recurrences are within the first 5 years after original treatment).

Most are asymptomatic.

Commonly displace the inferior alveolar nerve (IAN).

Will resorb roots of teeth.

Histologically will see a cyst lined by a thin layer of parakeratotic stratified squamous epithelium, which is usually 6–8 layers thick (rete ridge formation is inconspicuous).

Unilocular or multilocular radiolucency.

Displacement or resorption of teeth may be noted.

Treatment depends on size, extent, and location of lesion.

Enucleation and curettage with peripheral Ostectomy. Large cysts may be decompressed prior to treatment.

Cryotherapy with liquid nitrogen offers penetration up to 1.5 mm into the bone. It is difficult to work with as the peripheral tissues are at risk of injury and need to be protected. Additionally, if the inferior alveolar nerve is exposed, there is a high rate of paresthesia with reasonable recovery. Fractures of the mandible are also a known risk.

Chemical cauterization with Carnoy’s solution (mixture of ethanol, chloroform, glacial acetic acid, and ferric chloride). It is known that chloroform is a carcinogen, thus its usage has been banned in North America, rendering the use of Carnoy solution as banned. There is a modified form without chloroform, but the recurrence rate is considerably higher as chloroform is essential for its successful use.

Some authors advocate for en bloc resection with 1 cm margins due to the high recurrence rate and the aggressive nature of the lesion.

Age: second and third decade.

Occurrence : less than 1% of odontogenic cysts [1].

Calcifying odontogenic cysts (COCs) behave in a benign fashion.

Most cases are within bone, 5–17% are found extraosseous [1].

Maxilla and mandible have equal distribution as it relates to occurrence.

Unilocular or Multilocular with radiopaque structures that represent calcification.

Displacement or resorption of adjacent teeth may be seen.

May be associated with an unerupted tooth.

Conservative surgical removal.

Low recurrence rate.

Neoplasms derived from the tissues that are involved in odontogenesis (Table 8.1).

Most common epithelial odontogenic tumor.

Age: 30–70 years.

Most common in the mandible with a predilection for molar/ramus area.

Causes jaw expansion.

High rate of recurrence.

Unilocular or multilocular radiolucency.

Referred to as a “soap bubble” appearance when the loculations are large.

Referred to as a “honeycomb” appearance when the loculations are small.

Well-defined borders.

Root resorption of adjacent teeth may occur.

May simulate a dentigerous cyst when associated with an impacted tooth.

There are many histological subtypes (See Table 8.2).

13–21% of all cases of ameloblastoma [2].

Mimics a dentigerous cyst.

Most common in mandibular third molar region.

Younger age group than multicystic ameloblastomas.

Slow growing, paresthesia uncommon.

There are three histological variants (Table 8.3).

Unilocular radiolucency.

Arises from rests of dental lamina, or from the basal cell layer of the surface epithelium.

Exophytic mass of the tooth-bearing area.

Normally does not invade the underlying bone.

Less aggressive than the intraosseous counterpart.

Malignant (metastasizing) ameloblastoma: Metastasizes, but metastatic deposits are histologically benign.

Overall rate <1% of ameloblastomas [1].

Most metastases are to the lungs followed by the cervical lymph nodes.

Ameloblastic carcinoma: histologically malignant with hyperchromatism, increased nuclear-to-cytoplasmic ratio, and presence of high mitoses [1].

Enucleation and Curettage – this procedure is not considered curative and should be used for palliative purposes such as when there is a major anesthetic or surgical risk for the patient. The particulation of an ameloblastoma with enucleation and peripheral ostectomy is known to liberate tumor cells within the soft tissue and cause debilitating recurrences. This type of treatment has recurrence rates approaching 70–85% (recurrence usually occurs within 5 years) [1].

Marginal or block resection – curative form of treatment with resection using 1.0–1.5 cm bony margins and one uninvolved anatomical margin [3, 4]. Maxillary lesions may be more aggressive since they are not contained by cortical bone.

Unicystic ameloblastoma with intraluminal confinement – enucleation with long term follow up.

Peripheral ameloblastoma – treatment with local surgical excision with 2–3 mm margins. Recurrence to bone treated with further local excision.

Malignant ameloblastoma – En bloc resection of the primary tumor with wedge resection of the lung (71% cases travel to lung) and possibly chemotherapy [5]. Requires a multidisciplinary approach.

Ameloblastic carcinoma – resection with 2–3 cm bony lesions with neck dissection. Consideration for chemotherapy with platinum-based agents and radiotherapy.

Uncommon odontogenic tumor of the bone.

Commonly located in the mandibular premolar region.

Presents as a slow painless expansion.

Age: fourth–sixth decade.

No sex predilection.

Unilocular or multilocular radiolucency (Fig. 8.1).

Usually well-delineated lesion, but up to 20% have ill-defined borders [1].

May be associated with an impacted tooth.

CT scan may show an expanding mass.

Calcified structures (Liesegang ring calcifications) can be seen within the lesion. Amyloid-like material is found within the stroma.

Conservative local resection with peripheral ostectomy has a recurrence rate around 15% [1, 6].

Some surgeons advocate for resection with 1–1.5 cm margins and an uninvolved anatomical barrier.

2/3rds seen in teenage females.

Location : Anterior maxilla more commonly than anterior mandible.

2/3rds seen in association with impacted canines.

Slow growing, usually asymptomatic.

Unilocular, well circumscribed.

Snowflake-like calcifications.

Conservative enucleation, removed easily from its bed due to a thick fibrous capsule.

Arises from odontogenic ectomesenchyme.

No sex predilection.

Occurs more commonly in the mandible than maxilla.

Young adults, 25–30 years of age [1].

Can cause expansion of the affected area and displace/resorb teeth.

Histologically will see a myxoid stroma containing spindle- and stellate-shaped cells.

Multilocular radiolucency is more common but soap bubble and honeycomb patterns do occur.

Curettage – used for palliation and small lesions.

Resection – curative form of treatment with resection using 1.0–1.5 cm bony margins and one uninvolved anatomical margin [7].

A distinct form of ossifying fibroma, which is confined to tooth-bearing area of jaws.

Third–fifth decade with a female predilection.

Occurs more commonly in the mandible.

Slow growing, painless, and may cause large expansion.

Well circumscribed, round radiolucent or radiopaque lesion.

Displacement of teeth.

Conservative enucleation for a small, well-demarcated lesion, as those lesions are usually encapsulated.

Large lesions require resection with 5 mm borders. No need to remove involved soft tissue as tumor is encapsulated.

Solitary lesion found in continuity with a tooth root.

Teeth are normally vital.

Site: mandibular premolar or molar.

Age: most patients are less than 30 years old.

May have expansion and discomfort.

Well-defined dense radiopaque mass in continuity with the tooth root with a radiolucent halo around the lesion.

Periodontal ligament space surrounds the mass to distinguish from hypercementosis.

Excision, often with loss of involved tooth (low recurrence rate).

May also consider endodontic treatment with root resection.

First and second decade.

Slightly more common in males.

Posterior mandible more commonly involved.

Bony expansion.

Unilocular or multilocular radiolucency with well-defined borders.

Commonly associated with unerupted tooth.

Cortical expansion common.

Conservative surgical excision is recommended initially, with close follow up.

More aggressive excision for recurrent lesions.

Ameloblastic fibrosarcoma may develop in the setting of recurrent ameloblastic fibroma.

Third decade of life.

Predilection for the mandible.

Rapid clinical growth, often with pain and swelling.

Malignant counterpart of ameloblastic fibroma.

May arise de novo or from pre-existing ameloblastic fibroma.

Poorly defined destructive radiolucency.

Unilocular or Multilocular.

Expansile.

Radical surgical excision with 1–1.5 cm margins and uninvolved margin.

Lesions do not usually metastasize, but patients may die from uncontrolled local disease [8].

Younger population than ameloblastic fibroma (average age of 9) [1].

Mandible is affected more commonly than maxilla

No longer considered a separate entity by the WHO but a developmental stage of odontoma.

Well-defined unilocular or multilocular lesion.

Contains calcifications and often an unerupted tooth.

Enucleation and curettage.

The most common odontogenic tumor.

Compound odontomas are more common in anterior maxilla. Complex odontoma are found in the posterior region of either jaw.

Compound odontoma: appears as a small, tooth-like structure often surrounded by a radiolucent halo.

Complex odontoma: radiopaque mass also surrounded by a radiolucent rim.

Odontomas may be found associated with a tooth that has failed to erupt.

Excision .

Fibro-osseous lesions – disease processes characterized by normal bone being replaced by fibrous tissue containing a mineralized product.

Characterized by normal bone being replaced by fibrous tissue.

Associated with a GNAS gene mutation/deletion. The timing of the mutation during embryogenesis determines the extent of involvement.

Can involve one bone if mutation is late (monostotic) or multiple bones (polyostotic) if mutation is early on.

Lesion appears with “ground glass” opacity and poorly defined margins. Periapical radiographs often demonstrate an ill-defined lamina dura (Fig. 8.2)

Conservative management is the treatment of choice.

Patients with minimal cosmetic and functional issues may not require surgical treatment.

Surgical contouring, shaving, and debulking may be performed for the purpose of severe cosmetic deformity and functional problems. Combined orthodontic treatment and orthognathic surgery may be needed should a malocclusion ensue

High concern for blood loss after surgery, consider blood banking prior to surgery.

Complete surgical removal should be considered for aggressive lesions or lesions refractory to repeated debulking.

Radiation is contraindicated due to the risk of post irradiation sarcoma development.

Bisphosphonates may help to relieve bone pain (must consider the risk of MRONJ should subsequent surgery be needed).

Common in Black females, fourth–fifth decade of life.

Teeth are vital.

Radiographic and clinical findings can lead to a presumptive diagnosis (black female with multiquadrant or lower anterior teeth involvement).

Pathological entity in which bone is replaced by a cementum-like material.

Teeth are vital.

Radiographic and clinical findings can lead to a presumptive diagnosis (Black female with multi-quadrant or lower anterior teeth involvement).

Lesions are not neoplastic and, therefore, surgical removal is usually not necessary

Sclerotic lesions are hypovascular, which makes them prone to necrosis/infection from minor traumatic insults (e.g., extractions/implant placement).

Patients with COD should have regular dental prophylaxis and follow up to prevent dental disease leading to tooth loss (periodontitis/caries).

Patients with evidence of osteomyelitis should undergo debridement with saucerization.

Intraosseous lesion that may exhibit nonaggressive (most cases) or aggressive behavior.

Nonaggressive lesions grow slowly, expand bone, are painless, and do not resorb roots or cortical bone.

Aggressive lesions will be symptomatic, occur in younger patients with rapid growth.

Unknown origin – widely assumed to be trauma induced (but little supporting evidence).

Female predilection (2×).

The majority of cases are seen before the third decade of life, with a peak between the ages of 5 and 15.

Most cases involve the mandible (usually anterior mandible).

Nonaggressive lesions are usually discovered on routine radiographic examination or as a result of painless expansion.

Aggressive lesions tend to be aggressive resulting in pain, expansion, paresthesia, root resorption, and tooth displacement.

Histologically similar to brown tumors of hyperparathyroidism. Parathyroid hormone assay for primary hyperparathyroidism levels (with hypercalcemia) or for secondary hyperparathyroidism (with hypocalcemia) not routinely required as earlier concerning signs should be evident. Alkaline phosphatase elevation not necessarily needs to be assayed as it is normally elevated in growing children. CGCs demonstrate multinucleated giant cells within a spindle mononuclear cell stroma histologically.

Well-delineated unilocular or multilocular radiolucency (Fig. 8.4).

Displace teeth.

Resorb interradicular bone.

Enucleation and curettage with peripheral ostectomy, recurrence rate 20% (more frequently in large lesions).

En bloc resection with 1 cm margins for recurrent lesions.

Soft tissue equivalent of central giant cell granuloma.

Caused by trauma or irritation.

Common tumor of the oral cavity. Part of 3Ps (1) Pyogenic Granuloma (2) Peripheral Ossifying Fibroma (3) Peripheral Giant Cell Granuloma.

Normally smaller than 2 cm with a sessile or pedunculated base.

Blue/purple in color.

Female predilection.

Common age 30–60.

Treatment is excision down to the bone.

The medications implicated in MRONJ are antiresorptive medications and antiangiogenic medications.

Bisphosphonates and RANK ligand inhibitors are antiresorptive medications. These medications work by diminishing or altering osteoclasts, the cells responsible for bone resorption. RANK ligand inhibitors prevent osteoclast differentiation while bisphosphonates inhibit osteoclast function and increase osteoclast apoptosis. These medications tend to concentrate in areas of bone repair and remodeling possibly explaining their affinity for the jaws and the selectivity of osteonecrosis in this area.

Oral bisphosphonates are most commonly used for the treatment of osteoporosis and osteopenia. They are less commonly used for Paget’s disease of bone and osteogenesis imperfecta.

Intravenous bisphosphonates for the treatment of osteoporosis are also available as once yearly zoledronic acid and four times yearly ibandronate infusions. Intravenous bisphosphonates are also used for the management of bone metastases of solid tumors, especially breast, prostate, and lung cancers as well as the lytic lesions of multiple myeloma. The RANK ligand inhibitor denosumab is also used to treat osteoporosis and manage bone metastasis (See Tables 8.4 and 8.5 for a list of medications associated with MRONJ).

Antiangiogenic medications prevent the formation of new blood vessels and are used as a cancer treatment. They include the classes of drugs known as tyrosine kinase inhibitors and monoclonal antibodies inhibiting vascular endothelial growth factor. There is currently little research on the association between osteonecrosis and these medications, but reports indicate that a low risk exists.

The 2014 AAOMS position paper on MRONJ requires three characteristics to be present to distinguish MRONJ from other conditions [9]:

Radiographic changes are often seen before clinical evidence of necrosis and include increased radiopacity in the areas of increased bone remodeling such as tooth-bearing alveolar ridges.

Periosteal hyperplasia is occasionally seen.

In severe cases, a moth-eaten radiolucency with central sequestra is seen.

Stage 1 – Exposed and necrotic bone or fistulae that probe to bone in asymptomatic patients with no evidence of infection.

Stage 2 – Exposed and necrotic bone or fistulae that probe to bone in symptomatic patients with evidence of infection.

Patients should be evaluated for both acute and potential sources of oral infection prior to beginning bisphosphonate therapy. Patients with dentures should be evaluated for areas of trauma, as well. Sources of infection should be eliminated and bisphosphonate treatment initiation should be delayed until there is adequate osseous healing (takes about 1 month if conditions permit). Excellent oral hygiene should be stressed.

For patients taking bisphosphonates for osteoporosis for 4 years or more or for those who are taking bisphosphonates along with systemic corticosteroids or antiangiogenic agents, a drug holiday should be considered beginning 2 months prior to dentoalveolar surgery and continuing until osseous healing is complete. A drug holiday is not necessary for osteoporosis patients on bisphosphonates for less than 4 years.