persistent chronic purulent tonsillitis. In 2009, an association between biofilms and tonsilloliths was shown. Central to the biofilm concept is the assumption that bacteria form a three dimensional structure, dormant bacteria being in the center to serve as a constant nidus of infection. This impermeable structure renders the biofilm immune to antibiotic treatment. By use of confocal microscopy and microelectrodes, biofilms similar to dental biofilms were shown to be present in the tonsillolith, with oxygen respiration at the outer layer of tonsillolith, denitrification toward the middle, and acidification toward the bottom. Diagnosis Diagnosis is usually made upon inspection. Tonsilloliths are difficult to diagnose in the absence of clear manifestations, and often constitute casual findings of routine radiological studies. Classification Tonsilloliths or tonsil stones are calcifications that form in the crypts of the palatal tonsils. They are also known to form in the throat and on the roof of the mouth. Tonsils are filled with crevices where bacteria and other materials, including dead cells and mucus, can become trapped. When this occurs, the debris can become concentrated in white formations that occur in the pockets. Tonsilloliths are formed when this trapped debris accumulates and are expressed from the tonsil. They are generally soft, sometimes rubbery. This tends to occur most often in people who suffer from chronic inflammation in their tonsils or repeated bouts of tonsillitis. They are often associated with post-nasal drip. Giant Much rarer than the typical tonsil stones are giant tonsilloliths. Giant tonsilloliths may often be mistaken for other oral maladies, including peritonsillar abscess, and tumours of the tonsil. Differential diagnosis Imaging diagnostic techniques can identify a radiopaque mass that may be mistaken for foreign bodies, displaced teeth or calcified blood vessels. CT scan may reveal nonspecific calcified images in the tonsillar zone. The differential diagnosis must be established with acute and chronic tonsillitis, tonsillar hypertrophy, peritonsillar abscesses, foreign bodies, phlebolites, ectopic bone or cartilage, lymph nodes, granulomatous lesions or calcification of the stylohyoid ligament in the context of Eagle syndrome (elongated styloid process). Differential diagnosis of tonsilloliths includes foreign body, calcified granuloma, malignancy, an enlarged temporal styloid process or rarely, isolated bone which is usually derived from embryonic rests originating from the branchial arches. Treatment If tonsil stones do not bother a person, no treatment is needed. Otherwise gargling saltwater and manual removal may be tried. Chlorhexidine or cetylpyridinium chloride may also be tried. Surgical treatment may