Alginate powder is unstable on storage in the presence of moisture or in warm temperatures. They are elastic enough to be drawn over the undercuts, but tear over deep undercuts and are not dimensionally stable on storing due to evaporation. Īlginate materials possess the qualities of good surface detail and faster reaction at higher temperatures. Alginates are used for impressions in orthodontic models, sports mouth guards, bleaching trays, and more. Yet very few people can make alginate impressions just right the first time therefore, it becomes mandatory to understand the material and follow certain fundamental guidelines for flawless, predictable impressions, and hence avoid repeat impression/restorations. Alginate is one of the most frequently used impression materials, and it is simple, cost-effective, and an indispensable part of dental practice. Irreversible hydrocolloid impressions form an inseparable part of indirect restorations. Alginate is an elastic, irreversible hydrocolloid impression material. Irreversible hydrocolloid can be used in preliminary impressions, provisional crown-and-bridge impressions, study models, and opposing dentition impressions. Alginates remain as an economical option and easily manipulated impression material. Agar-agar impression materials are no longer used in clinics because of the inconvenience of manipulation, whereas alginates are still popularly advocated. The use of agar-agar was not convenient as it required special equipment such as heaters, syringes, and water-cooled rim-lock trays. All impression materials with agar-agar component have a jelly-like substance which becomes soft when heated and hardens when cooled. Agar was first introduced into dentistry for recording crown impressions in 1937 by Sears and was the first elastic impression material available. It is fundamentally a hydrophilic, emulsoid polysaccharide. Inelastic impression materials include impression waxes, impression compound, impression plaster, and metallic oxide pastes.Īgar-agar is an organic colloid obtained from the cell wall of red seaweed. Elastic impression materials include the following: reversible hydrocolloid, irreversible hydrocolloid, polysulfide, polyether, addition silicone (polyvinyl siloxane ), condensation silicone, and vinyl polyether siloxane. Hence, conventional impression materials are of two subtypes: elastic and inelastic. Impression materials can be categorized on the basis of their composition, setting reaction, and setting properties, but a commonly used system is based on the properties after the material has set. Ĭlassification of Dental Impression Material A systematic knowledge of these concepts is essential if the clinicians are to produce accurate reproductions of oral structures. Along with this, all these materials have different indications and contraindications for use. Both physical and chemical properties of all the impression materials are different from each other. In today's modern field of dentistry, numerous impression materials are available. Dental impression materials in prosthodontics: An overview for the general dentist. How to cite this URL: Arqoub MA, Rabi T, Arandi NZ. How to cite this article: Arqoub MA, Rabi T, Arandi NZ. Keywords: Alginate, impression material, prosthodontics Hence, in the present review, we aim to highlight some of the important aspects of dental impression materials used in prosthodontics. The accuracy and dimensional stability of impression materials are of paramount importance to the accuracy of fit of the resultant prosthesis. Impression making is a routine procedure carried out at the start of any prosthodontic procedure. Dental impression creation is the procedure of formulating a negative replica of the teeth and oral tissues, into which different die materials can be processed to create working analogs.
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