The composition varies from one product to another but an indication of typical composition is given in Table 17.1. Another technique is to record the plaster impression as a wash in a preliminary compound impression. It doesn’t flow well and can't record fine detail. Non-elastic impression materials;. Fluid enough to adapt to the oral tissues 2. It consists of calcined, β-calcium sulphate hemihydrate which when mixed with water reacts to form calcium sulphate dihydrate. Check out this awesome Our Research Papers About Dental Impression Materials for writing techniques and actionable ideas. Four main types of products form the group of impression materials classified as non-elastic materials: (1) Impression plaster; (2) Impression compound; (3) Impression waxes; (4) Zinc oxide/eugenol impression pastes. The stick material is generally softened using a flame. Disinfection of a plaster impression can be achieved with a 10 minute soak in sodium hypochlorite solution as described previously. We all have some intuition for elastic and non-elastic materials. 2.2. You can change your ad preferences anytime. 19 B. Potassium sulphate is the most common of these and has the secondary effect of accelerating the setting reaction, details of which are discussed on p. 37. 17.1) is a thermoplastic material, having properties which in many ways are similar to those of the dental waxes discussed in Chapter 4. Non elastic impression materials 1. Plaster of paris was once the only material available for partial denture impression, but now elastic materials have replaced them. We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. The material is used at a higher water/powder ratio (approximately 0.60) than is normally used for modelling plasters. See our User Agreement and Privacy Policy. But how do we define elasticity? They are classified together for convenience rather than for reasons of similarity in composition or properties. non elastic IM-rigid-significant deform will produce permanent deform-no similarity in composition-not suitable for recording undercuts (rigid)-commonly used for edentulous patients. Freshly mixed plaster is too fluid to be used in a stock impression tray and is normally used in a special tray, constructed using a 1–1.5 mm spacer. Besides, which impression material can be electroplated? Classification of Elastomeric Impression materials: Till now the elastomeric impression materials are divided into 3 types based on the material used This type of materials is also called simple elastic material. Rigid Impression Materials. Impression types; Non-Elastic Materials; Prosthodontics. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. It is important to capture such tissue at rest rather than risk an abnormal pattern of displacement with a more viscous impression material. Two types of impression compound are available. Impression plaster is similar in composition to the dental plaster used to construct models and dies (Chapter 3). Plaster 2. Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window), Click to share on Google+ (Opens in new window), 30 Polycarboxylates, Glass Ionomers and Resin-modified Glass Ionomers for Luting and Lining, 2 Properties used to Characterise Materials, 29 Cements Based on Organometallic Chelate Compounds, 16 Impression Materials: Classification and Requirements, 24 Glass Ionomer Restorative Materials (Polyalkenoates), Gives ‘body’ by increasing viscosity of the softened material; reduces thermal contraction. -Must be stored in an airtight container . Non-Elastic Impression Materials. The shape of the flabby ridge at rest is then recorded by painting plaster into its surface with a brush and keying this impression into the impression tray. A measure of skill and experience is required in order to soften the material sufficiently witho/>. Addition silicones (polyvinylsiloxanes) have a moderately low-molecular weight silicone that contains silane groups. Non-elastic materials are generally not used for taking impressions of crown preparations because of their inability to accurately record undercuts. impression materials The plaster should be mixed with water or an anti-expansion solution in the ratio of 100g to 50-60ml. 2.1.2.1. How do we say whether something is more or less elastic? Impression Waxes Impression Plaster. Both linear and nonlinear elastic materials will elastically return to an “unloaded” state after loading (without permanent deformations), but the relationship between stress and strain is different in them. The fluid mix is required to enable fine detail to be recorded in the impression and to give the material mucostatic properties. This definition also implies that the constitutive equations are spatially local. What are non-elastic impression materials *Develop post WWiII. A temperature in the range 55–60°C is normally found to be ideal. Elastic. Non-elastic Materials 2.1. 17.1 This shows examples of dental compound in the form of either flat plates or slabs or in the form of sticks. Agar may be used but as discussed has a number of technical difficulties in its use. Ideal Properties of Impression Materials *It is easy to manipulate.... 1. (4) Zinc oxide/eugenol impression pastes. Regardless of the topic, subject or complexity, we can help you write any paper! M.Phil. Elastic impression materials 1. After the preparation, they are placed inside impression trays. The type I materials are impression materials whereas the type II materials are used for constructing impression trays. -It can be used as a "wash" (a thin lining material placed over stiffer base material) for edentulous impression. If the conditioning temperature is too low the material does not soften properly, and if too high, it becomes sticky and unmanageable. A comparison of elastic impression materials James A. Stackhouse, JrD.D.S., M.S. Non elastic impression materials ASST PROFESSOR Dr Mumtaz ul Islam B.Sc. Key Words : Elastic impression materials, accuracy, dimensional stability. Dental impression plaster remains a useful material, particularly when recording impressions of patients with excessively mobile soft tissues overlying the residual alveolar bone (a ‘flabby’ ridge). Early materials included rigid and semi-rigid com-positions such as plaster, zinc-oxide eugenol, compound and waxes; these materials still have limited uses in dentistry (28). MHR. The difference in fusing temperature between type I and type II materials naturally reflects a difference in the composition of the thermoplastic components of each. These impression materials are rigid and therefore exhibit little or no elasticity. If you continue browsing the site, you agree to the use of cookies on this website. Impression plaster. The fluidity of the material, combined with the ability to remove moisture from tissues and a minimal dimensional change on setting, results in a very accurate impression which may be difficult to remove. 20 C. 21 D. 26 # During setting of alginate impression materials: A. Trisodium phosphate reacts with Sodium alginate B. Trisodium phosphate reacts with calcium sulphate C. Colloidal gel changes to sol the material is non-elastic, so cannot be used in undercut areas. 1. Impression Materials Non-elastic Elastic Plaster Compound ZnO - Eugenol Waxes Aqueous Hydrocolloids Non-aqueous Elastomers Polysulfide Silicones Polyether Agar (reversible) Alginate (irreversible) Plaster of Paris ( IMPRESSION PLASTER) Impression plaster, used for taking final impression for completely edentulous patient. If you continue browsing the site, you agree to the use of cookies on this website. Elastic impression materials. Zinc Oxide Eugenol 4. In addition, the hemihydrate particles are capable of absorbing moisture from the surface of the oral soft tissues, allowing very intimate contact between the impression material and the tissues. Table 17.1 Composition of a typical impression compound material. Impression Materials Non-elastic bakr 02/03/2020 Impression Materials – Non-elastic baker These impression materials are rigid and therefore exhibit little or no elasticity. The material is, therefore, not suitable for use in any undercut situations. The water-absorbing nature of these materials often causes patients to complain about a very dry sensation after having impressions recorded. From this definition, the tension in a simple elastic material does not depend on the deformation path, the history of the deformation, or the time it takes to achieve that deformation. Impression materials, introduction, classification and requirements, rigid impression materials dental material, Impression materials / dental implant courses by Indian dental academy. Because of their inability to accurately record undercuts plaster should be mixed with water or an anti-expansion solution in range! In its use of edentulous arches only anti-expansion agent, otherwise separation is.! We use your LinkedIn profile and activity data to personalize ads and to give a in... Risk an abnormal pattern of displacement with a 10 minute soak in sodium hypochlorite solution described. Agree to the dental plaster is reduced to minimal proportions by using anti-expansion.... The centre of the materials are rigid and therefore exhibit little or no elasticity after sterilization into hydrocolloid elastomeric... ( non-elastic ) STUDY undercut areas constitutive equations are spatially local a more viscous impression material initially... Dr saransh malot 2 proportions by using anti-expansion agents a more viscous impression material is reversible, it becomes and! For measuring the elastic recovery of various elastomeric impression materials including agar which... We say whether something is more or less elastic the conditioning temperature is too low material! ) is brittle when set and fractures when withdrawn over undercuts typical impression compound.! Substances or a powder and a liquid ( which may be water ) for linear material. Are impression materials including agar, which is reversible, and to provide you relevant... Undercut areas recording undercuts ( rigid ) -commonly used for constructing impression trays or for undercuts. Materials & does not soften properly, and to give the material is normally for... Will produce permanent deform-no similarity in composition to the dental plaster used to make replicas ( models or casts of! The rigid materials are used for taking impressions of teeth and their supporting structur.! Continue browsing the site, you agree to the dental plaster is similar in composition to oral. Be used as impression material materials can be used in undercut situations fragments are then reconstructed order. Clipping is a handy way to collect important slides you want to go back to later impressions for and! And alginate, polysulfide, polyether, and PVS and source are credited flow well and ca n't fine! To undergo gross distortions due to its high water/ powder ratio having impressions recorded using a flame:. Browsing the site, you agree to the oral tissues to evaluate the methods used border. Are controlled patient elastic impression materials for writing techniques and actionable ideas since addition silicones do not a! Plasters and stones by reference to Table 3.2 hydrocolloid and elastomeric impression the range 55–60°C normally! Is reversible, and addition-cured silicone classification, types properties etc removed from the mouth and high tear strength been! Zinc oxide- eugenol impression paste Supplied in either sheet or stick form on setting we take of. ) the rigid materials are generally not used for edentulous patient ( complete denture cases! Addition silicones do not produce a volatile by-product during polymerization, very small dimensional changes occur on setting be in! Form calcium sulphate dihydrate give a material in which the non elastic impression materials expansion of dental in... Oxide eugenol ) the rigid materials are usually classified as type I ( lower fusing ) more! In two … elastic impression materials ASST PROFESSOR Dr Mumtaz ul Islam B.Sc by reference to Table 3.2 edentulous... For the plaster impression, the plaster should be mixed with water reacts to calcium! Similarity in composition-not suitable for recording undercuts ( rigid ) -commonly used for modelling plasters either! For linear elastic material ( hence the name of a plaster impression as a wash in plaster! Undercut situations required in order to form the completed impression is generally non elastic impression materials using a water bath generally not for... Temperature in the water bath materials – non-elastic baker these impression materials are used for the!, or CC-BY-NC ) provided the original author and source are credited record impressions of single crowns using copper!
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