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In microscopy, negative staining is an established method, often used in diagnostic microscopy, for contrasting a thin specimen with an optically opaque fluid. In this technique, the background is stained, leaving the actual specimen untouched, and thus visible. This contrasts with positive staining, in which the actual specimen is stained.
Chlorhexidine (antiseptic mouthwash) binds to tannins, meaning that prolonged use in persons who consume coffee, tea or red wine is associated with extrinsic staining (i.e., removable staining) of teeth. [14] Cetylpyridinium chloride, which is found in many antimicrobial mouthwashes, can result in staining due to dead bacterial residue. [15] [16]
Coloured compounds from these sources are adsorbed into acquired dental pellicle or directly onto the surface of the tooth causing a stain to appear. [7] Dental plaque: Dental plaque is a clear biofilm of bacteria that naturally forms in the mouth, particularly along the gumline, and it occurs due to the normal development and defences of the ...
Unlike negative staining, positive staining uses basic dyes to color the specimen against a bright background. While chromophore is used for both negative and positive staining alike, the type of chromophore used in this technique is a positively charged ion instead of a negative one. The negatively charged cell wall of many microorganisms ...
Calculus was a term used for various kinds of stones. This spun off many modern words, including calculate (' use stones for mathematical purposes '), and calculus, which came to be used, in the 18th century, for accidental or incidental mineral buildups in human and animal bodies, like kidney stones and minerals on teeth. [3]
However, Pierre Fauchard, the father of modern dentistry, is credited for the introduction of tooth polishing to remove dental stains. Early polishing pastes consisted of finely ground coral, egg shells, ginger or salt. [4] Within the last century, Alfred Fones, the founder of dental hygiene, began educating students on coronal tooth polishing ...
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Uranyl acetate is extensively used as a negative stain in electron microscopy. [3] Most procedures in electron microscopy for biology require the use of uranyl acetate. Negative staining protocols typically treat the sample with 1% to 5% aqueous solution.