But how do we define elasticity? The compound is deliberately moved during setting to create space for the plaster wash. Impression Plaster 3. With other materials the tray is simply seated home in a single movement. Hydrocolloid materials include agar, which is reversible, and alginate, which is irreversible. The material is weak and easily fractured due to its high water/ powder ratio. The tray may be constructed from acrylic resin or shellac. 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 5. 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. -It can be used as a "wash" (a thin lining material placed over stiffer base material) for edentulous impression. Besides, which impression material can be electroplated? 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. The properties of impression plasters can be compared with those of model plasters and stones by reference to Table 3.2. -Must be stored in an airtight container . This definition also implies that the constitutive equations are spatially local. Key Words : Elastic impression materials, accuracy, dimensional stability. Impression materials A brief introduction Dr saransh malot 2. Impression compound must be heated in a water bath and then moulded onto the impression tray. Adhesive restorative materials: bonding of resin-based materials;. Non-Elastic Impression Materials. the material is non-elastic, so cannot be used in undercut areas. 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. 2.1.2.1. Two types of impression compound are available. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Elastic impression materials. If the conditioning temperature is too low the material does not soften properly, and if too high, it becomes sticky and unmanageable. 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. General Comments – Impression materials are used to make replicas (models or casts) of t eeth and other oral tissues. They are easy to handle and their accuracy is pretty good. 4. reproduction in any medium for non commercial use (NonCommercial, or CC-BY-NC) provided the original author and source are credited. 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. It is considered, that for optimal results, type I impression compound should undergo considerable flow at temperatures above 45°C but flow should be minimal at or below 37°C. * College of Medicine and Dentistry of New Jersey, New Jersey Dental School, Jersey City, N. J. T -L e ests for accuracy and other characteristics of elastic impression materials generally fall into one or more categories. In this video, we talk about various impression materials including agar, alginate, polysulfide, condensation silicone, polyether, and PVS. Any significant deformation produces a permanent deformation. Fluid enough to adapt to the oral tissues 2. -Very rigid and will break rather than bend -Absorb water from air. They are used mainly for edentulous patient 6. 1. Both the temperature and time of conditioning in the water bath affect the performance of the material. Zinc Oxide Eugenol 4. MHR. A retarder, such as borax, is normally incorporated, in order to give a material in which the setting characteristics are controlled. To separate cast from the impression, use warm water. The type I materials are impression materials whereas the type II materials are used for constructing impression trays. We all have some intuition for elastic and non-elastic materials. Are those that set to a rigid consistency . In this video, we will explore the true meaning of elasticity. It is important to capture such tissue at rest rather than risk an abnormal pattern of displacement with a more viscous impression material. Looks like you’ve clipped this slide to already. These are usually classified as type I (lower fusing) and type II (higher fusing). Elastic impression materials 1. It’s linear for linear elastic material (hence the name) and more complex in a nonlinear case. (4) Zinc oxide/eugenol impression pastes. 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). Ideal Properties of Impression Materials *It is easy to manipulate.... 1. They can’t record the undercut area Following setting, the plaster impression material is very brittle. Impression compound (see Fig. You can change your ad preferences anytime. 2.1.1. The conditioning time must also be carefully monitored. 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. Glass-ionomer restorative materials (polyalkenoates);. Abstract This study was conducted to evaluate the methods used for measuring the elastic recovery of various elastomeric impression materials. Elastic impression materials - abhishek kavlekar. Impression materials Elastic Chemical reactions Irreversible Alginate Elastomers Polysulphides Polyethers Condensation silicon Addition silicon Temperature change Reversible Agar hydrocolloid Chemical reactions Irreversible Plaster of Paris ZnO Eugenol Temperature change Reversible Impression … 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 impression materials: Hydrocolloids;. As stated above, there are times clinically where the accuracy of an alginate impression is not acceptable, particularly for the construction of fixed prosthodontics. – In dentistry, we take impressions of teeth and their supporting structur es. ASST PROFESSOR 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. 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. Any significant deformation produces a permanent deformation. The plaster should be mixed with water or an anti-expansion solution in the ratio of 100g to 50-60ml. Dentistry INTRODUCTION Historically, various materials have been used to make impressions for removable and fixed prosthodon- tics. These supporting structures include gingiva, a lveolar bone or residual ridge, hard and soft palate, and frenums, which are muscle attachments. 2.2. Some impression materials are not available in a sufficiently high-viscosity version for use in a stock tray, and these include zinc oxide–eugenol, polyether and polysulphide elastomers. Since addition silicones do not produce a volatile by-product during polymerization, very small dimensional changes occur on setting. It can undergo virtually no compressive or tensile strain without fracturing. 19 B. A brief introduction Dr saransh malot Impression materials. Zinc oxide- eugenol impression paste Supplied in two … Agar may be used but as discussed has a number of technical difficulties in its use. 1. 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. 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). A comparison of elastic impression materials James A. Stackhouse, JrD.D.S., M.S. This type of materials is also called simple elastic material. The stick material is used for border extensions on impression trays or for recording impressions of single crowns using the copper ring technique. 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. The technique for insertion of the impression into the mouth involves ‘puddling’ the impression into place. These impression materials are rigid and therefore exhibit little or no elasticity. Disinfection of a plaster impression can be achieved with a 10 minute soak in sodium hypochlorite solution as described previously. 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. Table 17.1 Composition of a typical impression compound material. Rigid impressions (impression compound & zinc oxide eugenol) The rigid materials are usually used to record impressions of edentulous arches only. Here are the topics. 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. Now customize the name of a clipboard to store your clips. Impression types; Non-Elastic Materials; Prosthodontics. Fig. How do we say whether something is more or less elastic? Elastic. What are non-elastic impression materials *Develop post WWiII. Impression materials, introduction, classification and requirements, rigid impression materials dental material, Impression materials / dental implant courses by Indian dental academy. A factor which links the materials is their inability to accurately record undercuts. 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. While in the mouth they set in a reasonable amount of time. The material is used at a higher water/powder ratio (approximately 0.60) than is normally used for modelling plasters. 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. 17.1 This shows examples of dental compound in the form of either flat plates or slabs or in the form of sticks. Regardless of the topic, subject or complexity, we can help you write any paper! Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Rigid Impression Materials. Check out this awesome Our Research Papers About Dental Impression Materials for writing techniques and actionable ideas. 2/23/2016 17. The mix should be a smooth paste, free of air bubbles, which may appear on the surface of the impression leading to inaccuracy. … 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. The materials are poor conductors of heat and it may take several minutes for the centre of the material to become softened. Elastic impression materials: Synthetic elastomers;. Plaster of Paris . See our Privacy Policy and User Agreement for details. Elastic materials have a soft consistency but after setting, they become elastic. Rigid or non elastic materials classification, types properties etc. Non elastic impression materials ASST PROFESSOR Dr Mumtaz ul Islam B.Sc. Compound 3. They are classified together for convenience rather than for reasons of similarity in composition or properties. 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. Dental Impression Compound. 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. The composition varies from one product to another but an indication of typical composition is given in Table 17.1. It is therefore used for primary impressions … 2.1.2. Dentaljuce and Prosthodontics - this should go together well. 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. 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. Plastic flow if used in undercut situations dent... no public clipboards found this! Fixed orthodontic courses by Indian dent... no public clipboards found for this.... Paste Supplied in two … elastic impression materials – non-elastic baker these impression materials excess material is used at higher... ( higher fusing ) composition varies from one product to another but indication... 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