DENTAL / JAW CYST

A dental or jaw cyst is a closed sac formed by a distinct membrane or lining in the jaw bone. It usually contains fluid and causes erosion of nearby bone tissue. A true cyst will remain permanent until removed. A cyst appears as a black cavity in a x-ray film or screen.

Amongst the more common cysts found in the jaw bones are:

• Dentigerous cyst, which is associated with buried tooth
• Radicular cyst, which is associated with infection at the root tips of a tooth
• Primordial cyst, which is formed from residual cells from developing tooth buds.
• Keratocyst, a special category that has great propensity to recur following treatment.
• Unicystic ameloblastoma, an odontogenic tumour which is locally invasive.

A comprehensive resource for this topic can be found at: http://www.usc.edu/hsc/dental/PTHL312abc/312b/10/Reader/reader.html

DIAGNOSIS

Before a specific treatment can be prescribed, diagnosis must be made by biopsy whereby a whole cyst or part of the cyst is examined under the microscope (histologically). Whilst most jaw cysts are benign, some may be locally invasive or cancerous.

TREATMENT

There are three main treatment methods:

• Marsupialisation
• The cyst is surgically “burst” opened. As the cystic membrane merges with the oral mucosa, the bone defect refills. A time interval of up to a year may be needed and only the benign cyst-type is suitable for this treatment modality.
• Enucleation
• The lining of the cyst is separated from the bone and removed. This is the most common treatment modality as the cystic tissue is completely removed. The residual bone defect maybe further treated with liquid nitrogen (cryotherapy) or chemicals. Bone grafting is usually not necessary as the bone will regenerate with time.
• Excision or resection
• This is a radical treatment where adjacent bone tissue or structures are removed at the same time. There will be some debilitating effect and this is done for odontogenic (dental origin) tumours or cancerous cysts. The residual defect is usually bone-grafted and fixated with titanium bone plates. The bone that is grafted maybe taken from multiple sites such the hip bone, leg (fibula), rib or skull.

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