Associate Professor of Dentistry. Director of the USC Center for Biofilms. Division of Periodontology, Dental Hygiene & Diagnostic Sciences. Diplomat, American Board of Oral & Maxillofacial Pathology. View all posts by Parish Sedghizadeh, DDS, MS →
A cyst is a membranous sac or cavity of abnormal character containing fluid.
Indications for an Oral Cyst Aspiration
For a jaw bone cyst lesion or any large soft tissue oral mucogingival cyst, aspirate the cyst aspiration. To help diagnosis of erythematous, pseudomembranous candidiasis, or suspected herpetic lesions use exfoliative cytology.
The Sabouraud Agar Slant Culture test is used when fungal overgrowth of the oral tissues is suspected, and is used to confirm the diagnosis of a fungal infection. Other adjunctive methods for the diagnosis of oral candidiasis include exfoliative cytology using PAS-stain or KOH and biopsy.
The agar media contains three key ingredients: dextrose, peptones (pancreatic digest of casein), and peptic digest of animal tissues.
Dextrose is added as the energy and carbon source, and peptones are a subunit of casein which is a protein found in milk and is a high quality source of amino acids. Peptic digests of animal tissues provide a nutritious source for the growth of fungi and yeasts.
The pH of the agar is adjusted to approximately 5.6 and it usually contains cycloheximide and chloramphenicol to prevent overgrowth of accompanying fungi and inhibit bacterial growth.
A positive culture will show creamy white colonies. A negative or positive result must be read at the 2 to 3-day time point; the agar slant culture test is invalid beyond 3 days. Keep the slant for at least two weeks before determining that the culture is negative.
Potential Causes of a Negative Result
There is no candida in the collected sample and the lesion is not due to fungal infection
The specimen was not collected properly
Antifungal treatment had been used prior to the collection of the specimen
The procedures were incorrect
The organism grew very slowly
Sample was taken from a hyperplastic candidiasis lesion