Stafne defect

Two classification systems were proposed to categorize Stafne bone cavity based on its depth[2] and content.

[6] It was originally proposed by Stafne that some parts of the submandibular gland could be trapped during mandibular ossification, causing well-circumscribed bony depression.

[8][9] Another hypothesis states that this bone cavity could result from the pressure exerted on the inner surface of the mandible due to the growth of sublingual or submandibular gland.

Computed tomography (CT) will show a shallow defect through the medial cortex of the mandible with a corticated rim and no soft tissue abnormalities, with the exception of a portion of the submandibular gland.

Neoplasms, such as metastatic squamous cell carcinoma to the submandibular lymph nodes or a salivary gland tumour, could create a similar appearance but rarely have such well defined borders and can usually be palpated in the floor of the mouth or submandibular triangle of the neck as a hard mass.

The Stafne defect also tends to not increase in size or change in radiographic appearance over time (hence the term "static bone cyst"), and this can be used to help confirm the diagnosis.

No treatment is required,[5] but neoplastic processes (metastatic malignancy to the submandibular lymph nodes and/or salivary gland tumours) should be ruled out.

[4] It was previously known by many names, including static bone cyst,[14] Stafne idiopathic bone cavity,[15] and salivary gland inclusions in the mandible,[16] An early case of Stafne's defect has been discovered in a 7th-century BC adult male individual from Klazomenai, one of the 12 cities of the Ionian League (now in modern Turkey).

Dental panoramic radiograph showing Stafne defect in the right mandible, below the inferior alveolar nerve canal (arrowed, appears on lower left of image). This x-ray was taken for an unrelated assessment of wisdom teeth , and the Stafne defect was a chance finding.
Axial computed tomograph of the same person. The Stafne defect appears as a well corticated 1 cm round defect in the medial cortex of the mandible in the right angle of the jaw (arrowed).
Coronal computed tomograph of the same person (Stafne defect arrowed).