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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.
Unicolor plaque disclosing tablet Tricolor plaque disclosing gel—before and after. Disclosing tablets are chewable tablets that make dental plaque visible.. The tablets, sold over the counter in many countries, contain a dye (typically a vegetable dye, such as Phloxine B) that stains the plaque a bright color (typically red or blue).
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 ...
Phosphotungstic acid is used in histology as a component for staining of cell specimens, often together with haematoxylin as PTAH. It binds to fibrin, collagen, and fibres of connective tissues, and replaces the anions of dyes from these materials, selectively decoloring them. Phosphotungstic acid is electron dense, opaque for electrons.
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]
Fluoride varnish is widely used in the United Kingdom, following guidelines from multiple sources backing its efficacy. Public Health England, a UK government organisation sponsored by the Department of Health, released guidance in 2014 recommending fluoride varnish application at least twice yearly for children and young adults. [13]
Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. [1] Their defining characteristic is that their cell envelope consists of a thin peptidoglycan cell wall sandwiched between an inner ( cytoplasmic ) membrane and an outer ...
Tetracycline: A wide spectrum antibiotic used to treat multiple bacterial infections. If prescribed during permanent tooth eruption in the mouth, grey staining can occur on the erupting teeth, presenting as a grey band at the point of eruption. The severity of the stain can vary depending on the level of intake of tetracycline. [12]