Odontogenic Cysts


Radicular cyst (Apical, lateral, and residual cyst)

Paradental cyst (Inflammatory collateral, mandibular infected buccal, or buccal bifurcation)


Dentigerous (follicular) cyst

Eruption cyst

Gingival cysts of infants (newborn)

Calcifying odontogenic cyst

Odontogenic keratocyst (primordial cyst)→ Keratocystic odontogenic tumor (2008)

Lateral periodontal cyst

Glandular odontogenic cyst: sialo-odontogenic cyst

Nonodontogenic cysts

Nasopalatine duct (Incisive canal) cyst

Nasolabial (Nasoalveolar) cyst

Odontogenic Cysts

Inflammatory Cysts

Radicular Cysts


The radicular cyst is an odontogenic cyst of inflammatory origin with a chronic periapical granuloma precursor that matures from the stimulation of cell rests of Malassez present in the periodontal membrane [3, 4]. Radicular cysts have different classifications by location:

  • Periapical cyst: presents at the root apex.

  • Lateral radicular cyst: presents at the opening of lateral accessory root canals of affected teeth.

  • Residual cyst: remains after extraction of the affected tooth [2, 5].

Biology and Epidemiology

An inflammatory process stimulates proliferation of the rest of Malassez, and the center of the lesion degenerates and liquefies to form a cyst [1, 2, 5, 6]. The lesion forms a fairly well-defined periapical radiolucency which continues to enlarge via cell break down and hyperosmotic gradient resulting in transudation of the fluid into the lumen of the lesion [2, 5, 6].


  • The most common cystic lesion in the jaw, comprising up to 60 % of odontogenic cysts [2, 5, 6].

  • Clinical features: pain on palpation or percussion on decayed or traumatized teeth.

  • Often asymptomatic if the lesion is chronic in nature [2].

Differential Diagnosis

  • Odontogenic cyst: inflammatory (radicular cyst) vs. developmental (dentigerous cyst).

  • Odontogenic tumor: keratocyst odontogenic tumor, ameloblastoma.

  • Nonodontogenic bone lesions such as giant cell tumor.

Diagnosis and Evaluation

  • Physical examination:

    • Tooth is often nonvital.

    • Tenderness to palpation or percussion of affected teeth.

  • Imaging evaluation:

    • Periapical or panoramic radiographs: radiolucency around the apex of the involved tooth (Fig. 32.1).


      Fig. 32.1
      Periapical radiograph showing periapical radiolucency involving previously root canal treated tooth

    • Usually smaller than 1–2 cm in size but occasionally can be much larger [2, 7, 8].


Histologic examination shows a connective tissue wall with various thicknesses and degrees of inflammatory cell infiltrates. There are nonkeratinized, stratified squamous cells [1, 2, 48].


The offending tooth is often nonvital and requires root canal therapy to remove the pulpal tissue and eliminate bacterial load.

  • If the lesion is large, enucleation is required to eradicate the inflammatory cystic lesion and subsequent apicoectomy of the tooth with retrograde filling can be done.

  • If the offending tooth is nonrestorable, removal of the tooth is another method to eliminate the source of infection.

  • The residual cyst will require enucleation if it persists after extraction of the offending tooth.



  • Squamous cell carcinoma or epidermoid carcinoma potentially can arise from the epithelial lining of a radicular cyst [2, 8].

  • Secondary infections can occur which might require an additional incision and drainage procedure.

  • If the cysts enlarge and perforate into the cortical bone, pathologic fracture of the mandible is also a potential risk [2, 7].

Buccal Bifurcation Cyst (BBC)


The BBC, also previously known as the mandibular infected buccal cyst described by Stoneman and Worth in 1983, is a type of paradental cyst based on the WHO classification [9]. It is a rare inflammatory cyst of odontogenic origin. It is easily misdiagnosed as radicular cyst because radicular cysts are more common lesions and have a similar presentation [2, 911].

Lesions with similar characteristics have been called other names, such as “circumferential dentigerous cysts” by Thoma in 1964. Thoma described a cyst that involved the mandibular second molar with cystic development of the enamel organ around the neck of the tooth interfering with its eruption. The “inflammatory collateral dental cyst” was described by Main in 1970. It is histologically identical to the inflammatory radicular cyst and is associated with vital mandibular third molars that have chronic periocoronitis. In 1976, Craig called the cyst “juvenile paradental cyst.” He described the cyst around a vital third molar tooth and attachment to the buccal bifurcation [11].

Biology and Epidemiology

The BBC is inflammatory rather than developmental in origin. It also has distinct clinical and radiographic features which distinguish it from other inflammatory paradental cysts [2, 10].

  • The BBC develops on the buccal aspect of vital mandibular first molars and occasionally involves the second molars [911].

  • Etiology: unknown but many speculate that the inflammatory response in the dental follicle during eruption may be the inciting factor. As the mesiobuccal cusp of the first molar penetrates through the oral epithelium, it induces an inflammatory reaction in the connective tissue, causing epithelial proliferation and cyst formation [2, 711]. Alternatively, it is also believed that the inflammatory response from pericoronitis may stimulate cyst formation [911].

  • The BBC may be a variant of lateral periodontal cyst, and the cystic epithelium is derived from the cell rests of Serres, the cell rests of Malassez, the cells of the dental lamina, or the reduced enamel epithelium [9].

  • Age distribution: seen in children with a range of 4–14 years.


  • Site and age specific.

  • Patients may present with swelling and/or pain associated with the lesion.

  • They occur as a localized buccal swelling of the affected erupting molar [2, 8, 11].

Differential Diagnosis

  • Odontogenic cysts (BBC, radicular cyst, or dentigerous cyst).

  • Benign odontogenic tumors (ameloblastoma or keratocyst odontogenic tumor).

  • Nonodontogenic tumors (giant cell tumor, myxoma, or vascular malformation).

Diagnosis and Evaluation

  • Primarily based on the clinical and radiographic features.

Physical Examination

  • Swelling and tenderness over the affected molar area (usually mandibular first molar) as Stoneman and Worth reported in 1983 under the term mandibular infected buccal cyst.

  • Deep periodontal pocket on the buccal aspect of the involved vital tooth with an altered eruption pattern [6, 911].

  • Crown often is tilted buccally [912].

Imaging Evaluation

  • Panoramic or periapical radiograph supplemented by occlusal view radiograph are sufficient for diagnosis. The lesion appears as a U-shaped radiolucent lesion on the buccal aspect of the tooth covering the roots (Fig. 32.2). The periodontal ligament space (lamina dura) is intact and the cyst is unlikely to extend to the inferior border of the mandible. The buccal tilting of the tooth pushes the apices of the roots toward the lingual plate, and a buccal periosteal reaction is often evident. The lesion can be 1 cm in size [2, 913].


    Fig. 32.2
    a Panoramic radiograph demonstrating U-shaped radiolucency around the root of the lower, right first molar. Axial (b) and coronal (c) CT cuts show cortical perforation with a well-circumscribed lesion located on the buccal surface of the involved tooth

  • Computerized tomography (CT) scan: In today’s modern health care system, a CT scan is often used to better delineate the lesion (Fig. 32.2).


Histopathologic examination (Fig. 32.3) shows the cyst wall lined by nonkeratinizing, stratified, squamous epithelium and a fibrous stroma with chronic inflammation [911]. These findings are nonspecific, and are similar to those found in a radicular cyst. As a result, diagnosis cannot be made from the histopathologic features alone [9].


Fig. 32.3
a Histologic examination showing nonkeratinizing, stratified, squamous epithelium with spongiosis overlying chronically inflamed fibrous connective tissue. The specimen (b) shows the U-shaped lesion


Surgical treatment is successful with low recurrence.

  • Treatment options: curretage, marsupialization, enucleation, removal of the tooth.

  • Nonsurgical approaches: periodontal probing or daily irrigation of the buccal periodontal pocket with saline have been reported [9].

  • Some studies have suggested that these are self-resolving lesions because they are rarely seen in adults [2, 10, 13].

Dec 28, 2016 | Posted by in PEDIATRICS | Comments Off on Odontogenic Cysts

Full access? Get Clinical Tree

Get Clinical Tree app for offline access