Glass ionomer cement

A glass ionomer cement is a dental restorative material used in dentistry for dental fillings and luting cements. It is also now commonly used as an orthodontic bracket adhesive, either as a glass ionomer, or a glass ionomer-based cement. Glass-ionomer based cements are essentially hybrids of glass ionomers and another dental material, for example Resin-Modified Glass Ionomer Cements (RMGICs) and compomers (or modified composites). These materials are based on the reaction of silicate glass-powder (calciumaluminofluorosilicate glass)and polyalkenoic acid, an ionomer. Occasionally water is used instead of an acid, altering the properties of the material and its uses. This reaction produces a powdered cement of glass particles surrounded by matrix of fluoride elements and is known chemically as Glass Polyalkenoate. There are other forms of similar reactions which can take place, for example, when using an aqueous solution of acrylic/itaconic copolymer with Tartaric acid, this results in a glass-ionomer in liquid form. An aqueous solution of Maleic acid polymer or maleic/acrylic copolymer with Tartaric acid can also be used to form a glass-ionomer in liquid form. Tartaric acid plays a significant part in controlling the setting characteristics of the material.

Glass ionomer cement is primarily used in the prevention of dental caries. This dental material has good adhesive bond properties to tooth structure, allowing it to form a tight seal between the internal structures of the tooth and the surrounding environment. Dental caries is caused by bacterial production of acid during their metabolic actions. The acid produced from this metabolism results in the breakdown of tooth enamel and subsequent inner structures of the tooth, if the disease is not intervened by a dental professional, or if the carious lesion does not arrest and/or the enamel re-mineralises by itself. Glass ionomer cements act as sealants when pits and fissures in the tooth occur and release fluoride to prevent further enamel demineralisation and promote remineralisation. Fluoride can also hinder bacterial growth, by inhibiting their metabolism of ingested sugars in the diet. It does this by inhibiting various metabolic enzymes within the bacteria. This leads to a reduction in the acid produced during the bacteria’s digestion of food, preventing a further drop in pH and therefore preventing carious.

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