4. They are easy to handle and their accuracy is pretty good. A pigment such as alazarin red is also commonly used, in order to make a clear distinction between the impression and the model after casting of the model. impression materials Non-elastic materials are generally not used for taking impressions of crown preparations because of their inability to accurately record undercuts. It is important to capture such tissue at rest rather than risk an abnormal pattern of displacement with a more viscous impression material. Compound impression can be added or corrected. A two-stage technique is commonly used in which a special tray is made with appropriate spacing for zinc oxide/eugenol paste where the mucosa is well supported and having a window overlying the ‘flabby’ area. In physics, a Cauchy elastic material is one in which the stress / tension of each point is determined only by the current deformation state with respect to an arbitrary reference configuration. The setting expansion of dental plaster is reduced to minimal proportions by using anti-expansion agents. The plaster should be mixed with water or an anti-expansion solution in the ratio of 100g to 50-60ml. Elastomeric Impression materials: These are basically synthetic rubber based materials which were initially called as Rubber Impression materials but currently they are known as Non aqueous Elastomeric Impression materials. Impression Plaster 3. 19 B. BDS. Impression plaster is similar in composition to the dental plaster used to construct models and dies (Chapter 3). B.Sc. It consists of calcined, β-calcium sulphate hemihydrate which when mixed with water reacts to form calcium sulphate dihydrate. MHR. 17.1 This shows examples of dental compound in the form of either flat plates or slabs or in the form of sticks. Elastic impression materials: Hydrocolloids;. Any excess material is removed from the window and the impression re-seated in the mouth. Non-Elastic Impression Materials. Recently, new elastomeric impression materials with very high elastic recovery and high tear strength have been introduced. You can change your ad preferences anytime. Now customize the name of a clipboard to store your clips. Disinfection of a plaster impression can be achieved with a 10 minute soak in sodium hypochlorite solution as described previously. Table 17.1 Composition of a typical impression compound material. One technique for recording impressions of undercut areas, commonly used before the advent of elastic materials, was to allow the impression plaster to ‘set’ and then to fracture it in order to facilitate removal from the mouth. They are classified together for convenience rather than for reasons of similarity in composition or properties. Two types of impression compound are available. The sheet material is used for recording impressions of edentulous ridges, normally using stock trays. Impression materials. Elastic impression materials can be further divided into hydrocolloid and elastomeric impression. Non elastic They are used mainly for edentulous patient If you continue browsing the site, you agree to the use of cookies on this website. It doesn’t flow well and can't record fine detail. Dental impression making is the process of creating a negative form of the teeth and oral tissues, into which gypsum or other die materials can be processed to create working analogues. These are usually classified as type I (lower fusing) and type II (higher fusing). Fig. The base and catalyst are either 2 paste substances or a powder and a liquid (which may be water). Impression compound (see Fig. Requirements of direct filing materials and historical perspectives;. MHR. 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. Since addition silicones do not produce a volatile by-product during polymerization, very small dimensional changes occur on setting. In this video, we will explore the true meaning of elasticity. Looks like you’ve clipped this slide to already. General Comments – Impression materials are used to make replicas (models or casts) of t eeth and other oral tissues. Ideal Properties of Impression Materials *It is easy to manipulate.... 1. 1. Clipping is a handy way to collect important slides you want to go back to later. impression materials (non-elastic) STUDY. Non elastic impression materials 1. 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. Non-elastic Materials 2.1. Agar may be used but as discussed has a number of technical difficulties in its use. An impression of the bulk of the ridge is recorded in zinc oxide/eugenol paste. 17.1) is a thermoplastic material, having properties which in many ways are similar to those of the dental waxes discussed in Chapter 4. Elastic. These supporting structures include gingiva, a lveolar bone or residual ridge, hard and soft palate, and frenums, which are muscle attachments. It is capable of recording tooth and tissue details accurately , they cannot be removed from the mouth without fracture and reassembly . 2. Plaster of Paris . Impression Waxes Impression Plaster. elastic: susceptible to being stretched, compressed, or distorted and then tending to resume the original shape elastomeric impression material: a group of flexible chemical polymers, which are either chemically or physically cross-linked. 2.2. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Check out this awesome Our Research Papers About Dental Impression Materials for writing techniques and actionable ideas. How do we say whether something is more or less elastic? -Must be stored in an airtight container . -It can be used as a "wash" (a thin lining material placed over stiffer base material) for edentulous impression. Any significant deformation produces a permanent deformation. reproduction in any medium for non commercial use (NonCommercial, or CC-BY-NC) provided the original author and source are credited. Impression material • Any substance or combination of substances used for making an impression or negative reproduction Non Elastic Impression • They are impression materials which fracture or distort upon removal from the undercut area after setting. 1. A temperature in the range 55–60°C is normally found to be ideal. Uses of waxes in dentistry/certified fixed orthodontic courses by Indian dent... No public clipboards found for this slide. The composition varies from one product to another but an indication of typical composition is given in Table 17.1. Abstract This study was conducted to evaluate the methods used for measuring the elastic recovery of various elastomeric impression materials. Non-elastic impression materials: Impression plaster Impression compound Zinc oxide eugenol Impression waxes Impression Plaster / Plaster of Paris Composition: Plaster of … Glass-ionomer restorative materials (polyalkenoates);. 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. The water-absorbing nature of these materials often causes patients to complain about a very dry sensation after having impressions recorded. Impression plaster. Non elastic impression materials ASST PROFESSOR Dr Mumtaz ul Islam B.Sc. 2.1.2. The mixed impression material is initially very fluid and is capable of recording soft tissues in the uncompressed state. 1. 6. The materials are poor conductors of heat and it may take several minutes for the centre of the material to become softened. 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. But how do we define elasticity? 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. Rigid / Inelastic. ASST PROFESSOR M.Phil. These impression materials are rigid and therefore exhibit little or no elasticity. Rigid Impression Materials. 7. See our Privacy Policy and User Agreement for details. 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. Dentistry INTRODUCTION Historically, various materials have been used to make impressions for removable and fixed prosthodon- tics. After the preparation, they are placed inside impression trays. Besides, which impression material can be electroplated? Hydrocolloid materials include agar, which is reversible, and alginate, which is irreversible. 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. What are non-elastic impression materials *Develop post WWiII. Dentaljuce and Prosthodontics - this should go together well. Impression materials A brief introduction Dr saransh malot 2. Rigid or non elastic materials classification, types properties etc. Impression types; Non-Elastic Materials; Prosthodontics. The compound is deliberately moved during setting to create space for the plaster wash. As stated above, there are times clinically where the accuracy of an alginate impression is not acceptable, particularly for the construction of fixed prosthodontics. Comparative elasticity tests for elastomeric (non putty) impression materials Comparative elasticity tests for elastomeric (non putty) impression materials Blomberg, P. A. H.; Mahmood, S.; Smales, R. J.; Makinson, O. F. 1992-10-01 00:00:00 materials. 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. Classification of Elastomeric Impression materials: Till now the elastomeric impression materials are divided into 3 types based on the material used The lower fusing, type I impression materials may be supplied in either sheet or stick form. 2.1.1. 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 Fluid enough to adapt to the oral tissues 2. Key Words : Elastic impression materials, accuracy, dimensional stability. Elastic impression materials - abhishek kavlekar. Another technique is to record the plaster impression as a wash in a preliminary compound impression. Viscous enough to be retained in tray that is seated in the mouth 3. Compound 3. ZOE. Zinc Oxide Eugenol 4. If you continue browsing the site, you agree to the use of cookies on this website. Following setting, the plaster impression material is very brittle. Compatible with cast & die materials & does not need separating medium. -Very rigid and will break rather than bend -Absorb water from air. With plaster the tray is gently moved from side to side and antero-posteriorly to best take advantage of the handling characteristics of the material, particularly its fluidity. Chemical reactions Temperature change Irreversible Reversible Chemical reactions Alginate Agar hydrocolloid Irreversible Elastomers Plaster of Paris Polysulphides ZnO Eugenol Polyethers Condensation silicon Addition silicon Complete Dentures This module will cover complete dentures and include videos, pictures, text and references to assist you in making those most difficult of prosthetic replacements. A brief introduction Dr saransh malot Impression materials. Dental Impression Compound. Plaster 2. Elastic materials have a soft consistency but after setting, they become elastic. Before casting a plaster model in a plaster impression, the impression must be coated with a separating agent, otherwise separation is impossible. Dr Mumtaz ul Islam A retarder, such as borax, is normally incorporated, in order to give a material in which the setting characteristics are controlled. Rigid impression materials and types • Incapable to record undercut area • Impression plaster fractures on recovery others distorts • Impression plaster • Impression compound • Impression waxes • Zinc oxide eugenol pastes system 3. Others, such as impression compound (compo), plaster of Paris, alginate and the silicones are available in formulations that can be used with a stock tray. Non-elastic impression materials;. This type of materials is also called simple elastic material. The technique for insertion of the impression into the mouth involves ‘puddling’ the impression into place. The tray may be constructed from acrylic resin or shellac. 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). Are those that set to a rigid consistency . Four main types of products form the group of impression materials classified as non-elastic materials: They are classified together for convenience rather than for reasons of similarity in composition or properties. Resin-based filling materials;. 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. M.Phil. 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. PLAY. It can undergo virtually no compressive or tensile strain without fracturing. Impression compound must be heated in a water bath and then moulded onto the impression tray. Various elastomeric impression materials non-elastic bakr 02/03/2020 impression materials are rigid and therefore exhibit little or no elasticity of... Paris is seldom used as impression material is: a 17.1 composition of a plaster as... 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