<>/Metadata 479 0 R/ViewerPreferences 480 0 R>> Several materials are softened or melted by heating. Supplied as: sticks, cakes, & cones. Cleaning and sterilizing metal trays adds to the cost of their use. Classification and Use of Impression Materials. 6. It is interesting to note that dental impression materials are also used to make impressions for medical prostheses (such as artificial eyes) and forensic investigations (bite marks). Inelastic impression materials set hard and rigid compared with elastic impression materials and would “lock” around teeth if used on a dentulous patient. Impression Compound Sticks Green 1/4 Lb 15/Box. Wax used for taking impressions is solid at mouth temperature but is moldable at a temperature that is tolerated by oral tissues. Our traditional dental impression materials, tools and kits can help you efficiently create accurate dental impressions for a variety of applications, including crowns, bridges, inlays, overlays and implants. <> They are then loaded into an impression tray, placed in the mouth, and seated onto the tissues of interest. properly. List the oral structures from which impressions are made. Describe the various types of impression trays. These supporting structures include gingiva, alveolar bone or residual ridge, hard and soft palate, and frenums, which are muscle attachments. Hydrocolloid materials that gel by a physical change (cooling) are called, 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), General Rules for Handling Dental Materials, Clinical Aspects of Dental Materials 5th Edition. They are the most “runny” of the impression materials and best record the details of tooth preparations (small grooves, edges, and margins). In the gel state, two phases exist, much like a foam of soap bubbles. 4. After the cord has been in place for several minutes, it is usually removed, just before the impression is taken. Some are hard, much like paraffin wax that is used in canning jellies and jams. Because impression materials are used for a variety of purposes, the requirements of a particular procedure determine which impression materials can be used. Above 45°C and Type 2 which is high fusing with a … Edentulous impressions may use elastic or inelastic impression materials. If the orifice of one tube is larger than that of the other tube, then again, one should dispense equal lengths. A multitude of waxes are used in dentistry. Which of the following is an example of an inelastic impression material? After studying this chapter, the student will be able to do the following: 1. <> A preliminary impression is taken with a stock tray and an inexpensive material. With the dual-arch technique, the loaded tray (on both sides) is seated on the arch with the prepared tooth. List the desirable qualities of an impression material. Other uses require very exact (within 0.1%) replication of the size and shape of a preparation for the construction of a restoration or appliance. For Impressions of Edentulous mouth or of a single tooth in … Type 1 (impression plaster)-contain potato starch to render them soluble. Use for Impression Plaster. FIGURE 8.6. FIGURE 8.9. Gypsum products will be discussed in Chapter 9. The latter is mainly used for border moulding and recording the post-dam area. It is also very weak, and the technique must compensate for wax’s poor mechanical properties. Impression compound is supplied as sticks or cakes of material, as shown in Figure 8.7A. Type 2 Dental plaster (beta hemihydrate)-110-120 c (230-250F). Compare the properties, use, and cost of the above impression materials. X �Y()C��+����n��-�J����~��߃�����ǽ?? Describe the composition and setting mechanism of: 8. The replicas are used to construct restorations and other appliances. These processes are described in more detail in subsequent chapters. Viscosity is a measure of a liquid’s ability to flow. The chemistry of ZOE materials is covered in Chapter 7, Dental Cements. Elastic Impression Materials – Hydrocolloid Impression Materials For additional ancillary materials related to this chapter, please visit thePoint. The orifice of each tube is sized to provide the proper ratio of the two pastes when equal lengths are dispensed. 2.1.1 Type 1 - called ‘impressioncompound’, impressions in the oral cavity. If a replacement is available it will be used when we are completely out of stock on this item. Other impression materials set by a physical change when they cool, either by solidification or by gelation. In most instances, the patient will have had local anesthesia to ensure his or her comfort. Each impression material has its own advantages and disadvantages for use in dentistry. The cost of impression materials varies greatly, from pennies per impression to as much as several dollars. iii) Vigorous mixing. Paste–paste impression materials (and many other dental materials) come in tubes, much like toothpaste tubes. 2 0 obj Differentiate between a model, a cast, and a die. Equal lengths of material from each tube are dispensed. Solidification occurs when molten wax cools and goes from a liquid state to a solid state. Impression Compounds (All Colors) 02/21/19 Page 3 of 6 Section 7. The light-body material records the preparation and its margins, while the thicker material becomes the bulk of the impression. Retraction cord being placed in the sulcus during crown preparation. Today, however, ZOE materials have been replaced by newer materials, such as addition silicones. Examples are shown in. endobj Impression materials that set by chemical reactions to form elastic rubber materials are called thermoset. In general, thermoplastic materials are not as stable as are thermoset materials. 10. materials. Impression Plaster (Type I Gypsum) Impression Compound Tray Compound Zinc-Oxide Eugenol Impression Paste. Study models are not considered to be highly accurate reproductions of oral tissues. They can be categorised into either rigid impression materials (zinc oxide eugenol and impression compound) or elastic impression materials (alginate and silicone). Two techniques for the fabrication of custom trays for crown and bridge impressions are presented in detail in Chapter 29, Fabrication of a Custom Impression Trays. FIGURE 8.1. Zinc oxide–eugenol (ZOE) has been formulated for a wide variety of uses in dentistry, including as an impression material. Describe the various types of impression trays. Later, the wax is melted away and the mold is filled with a restorative material, such as gold. Colloids are discussed in Chapter 2, Materials Science and Dentistry. The retraction cord pushes the gingiva away from the tooth, as shown in Figure 8.6. The impression tray, which is filled with the high-viscosity material, is immediately seated over the light-body material. B. There are (from thinnest to thickest consistency) light-body, medium-body, monophase, heavy-body, and putty materials. Impression compound is wax with added filler to improve handling and stability. TYPE I Low Fusing - Green stick compound- 54 C Medium Fusing – Impression compound - 8. addition silicone Agar alginate Classification of Dental Caries and Restorations condensation silicones cost of Impression Materials impression compound Impression Materials Impression Materials system impression trays Inelastic impression materials Plaster polyether polysulfide types of Impression Materials uses of Impression Materials Wax Zinc oxide–eugenol 1 0 obj 5. Thus, if the size of the two orifices is the same, one should dispense equal lengths. Some are powders that are mixed with water; others are paste–paste systems. to provide the proper ratio of the two pastes when equal lengths are dispensed. A. 3. 6. Because impression materials are used for many purposes, a wide variety of products are available to make impressions of oral tissues. Gelation is the process by which gelatin, such as Jell-O, changes from a liquid state to a semisolid state when it cools. Cleaning and sterilizing metal trays adds to the cost of their use. Plastic disposable trays are very popular and work well with current infection control practices. Some uses are simply to produce a physical model of the oral tissues for study, called a study model. Several impression trays (from upper left, moving clockwise): a metal perforated tray for partially edentulous impressions, a solid metal tray for edentulous impressions, a metal tray for dentulous impressions, a bite registration tray, a plastic tray for dentulous impressions, and a custom tray. Select a Medical specialty site that best fits your needs. Red low heat compound has maximum visibility of detail and a working temp 115°F - 125°F. According to philips scienceof dental materials impression materials are classified on thebasis of setting and elasticity.Mode of setting rigid ElasticSet by chemicalreaction(irreversible)Impression plaster,zinc oxide eugenol.Alginate,polysulfide,polyether, silicone,Set by temperaturechange(reversible)Compound, waxes Agar hydrocolloid. TYPES 2.1 The material shall be of the following three types. Many kinds of impression materials come in a variety of viscosities. It is a thermoplastic material. �Xd4�¼�$(�,���Yb�x;��J�IK˜A��P�z{\:��b�+Vn��(vG�`˘d��)DF�4��nz�'��E6y��9�h9��0r���x�0�.��wCF�"�t���8q{c�>�?��J��E"���l�!E(@�?a���x����/���+�|���z�2��\^"`,�d�{\�Ũ0��� ���P�ׯ���z���p)�^���i\��e�F��������f�F�HD�(����S恧"J��;�! For edentulous impressions. {"2�2Yʐ��R!O�S�ϧb�C��ę3� ��ޓ.X�e��)��+rz���^A�� Putty materials are the thickest impression materials, but they can still record the details of a fingerprint. Therefore, alginate is an acceptable impression material for study models, but it is an unacceptable impression material for the fabrication of bridges, crowns, and inlays. Alginate materials are supplied as powders that are mixed with water as shown in Figure 8.9. The first phase is a solid carbohydrate polymer network, like the soap used to create a foam. TYPE I – SHEETS Recording Impression of edentulous ridge Manipulation: Compound softened in water bath kneaded with finger to improve qualities Temperature of water bath 55-60 C is ideal for 4-5 mins to ensure complete softening Henry Schein Medical A Henry Schein Company; Shop Our Specials Start shopping today; Browse Supplies Learn more about our robust product portfolio; Who We Are Dedicated to servicing a range of medical providers; What We Offer Partner with us for strategic growth A replica of a single tooth is called a die. Impression compound – wet kneading, putty consistency Elastomers. 8.5A). Models mounted on a simple articulator with a bite registration on the mandibular right quadrant made of impression material. Although the newer materials have little advantage in terms of performance and are much more expensive, the simple advantage of stocking one less impression material in the dental office is likely the reason for the declining use of ZOE impression materials. Many times, a retraction cord is placed in the gingival sulcus to facilitate crown and bridge impressions. Such trays are illustrated in Figure 8.2. FIGURE 8.2. 2. Impression materials are also classified as reversible (compounds and hydrocolloids) or irreversible (silicones, polyethers, and alginates). Colors – green, brown, red. Others say that custom trays are cost-effective because they make the impressions easier to take and accurate impressions result more frequently than with stock trays. To drive off part of the water of crystallization.-The principal component of dental plaster and stone is calcium sulphate hemihydrate. Cooperative research by the National Bureau of Standards and the American Dental Association. Monophase materials are designed to be used for both injection and in the tray. Describe the composition and setting mechanism of: Wax and impression compound Zinc oxide–eugenol (ZOE) 2.1.3 Type 3-called ‘tracing stick’, or ‘low heat compound’, suitable for taking impressions in the oral cavity. An effect, feeling, or image retained as a consequence of experience: Seeing the glacier made a big impression on us. There are exceptions, however, as the cord may be kept in place during the impression. The accuracy required by the restoration or prosthesis determines which impression materials can be used. Describe the effect of water and heat on the setting rate of polysulfides. Frequently, the cord will contain a hemostatic or astringent medicament to control bleeding. Note that the lengths dispensed, but not the volumes, are equal. e.g. The heated, softened, and moldable material is placed in an impression tray, resoftened, and then seated in the mouth. This table does not address all possible techniques. When the material has cooled to mouth temperature, it returns to a rigid state and is removed. Therefore, only one mix of monophase material is needed. The two pastes come in tubes, much like toothpaste, as shown in Figure 8.8. Custom trays are used to take final impressions for full dentures, inlays, crowns, bridges, and some removable partial dentures. Zoe impression paste, polysulfide. Impression compound is a stiff, thermoplastic material and is used by many dentists to make preliminary impressions for complete dentures, as shown in, warm alginate; it does not reverse back to the sol (fluid) state. In order to avoid the spread of pathogens from patients to patient, patient to health care personnel and health care personnel to patient, it is the duty of the health care policies makers to allocate the appropriate methods of cleaning, disinfectio… The compound is for taking full and partial impressions, and making preliminary impression trays. n. 1. C. Preliminary impression for a complete denture. And it is not unlikely that you may be asked to assist with a “final impression” appointment should the dental assistant not be present that day. Should you make athletic mouth guard or whitening trays, an impression will be a part of the appliance fabrication process. The use of a bite registration without a tray is shown in Figure 8.4. IMPRESSION COMPOUND Classification According to ADA specification no. Then, the wax piece is surrounded by a mold material. The ZOE impression materials set to a hard and brittle mass, which limits their use to impressions of edentulous ridges for removable dentures. Impression Compound Cakes, 8/Pkg Keystone Industries. Each coloured variant has a controlled working temperature. B. Tray with impression compound in a water bath. impression compound synonyms, impression compound pronunciation, impression compound translation, English dictionary definition of impression compound. Above 45°C and Type 2 which is high fusing with a fusion temperature of approximately above 70°C. Hydrocolloid materials that set via a chemical reaction are called irreversible hydrocolloids, or, more commonly, alginate. It is important to have an understanding of the various types of impression materials, their specific use, and their handling characteristics. Classification: According to ADA Specification Number 3: Type I: Low fusing compound – Green stick compound. (Courtesy of Dr. James Overberger, Morgantown, WV.). Custom trays are made on a model of the patient’s arch with acrylic or other resin. Because the thermal conductivity of impression compound is low, time and patience are required to soften the material properly. Handling and Storage Precautions for Safe Handling: Avoid contact with eyes, skin and clothing.Always wear impervious gloves, chemical safety goggles and protective clothing when handling this material. Final impression is made either using zinc oxide eugenol or with a medium viscosity elastomer. There are exceptions, however, as the cord may be kept in place during the impression. FIGURE 8.4. Type II: High fusing compound – tray compound. The cord moves the gingival tissue slightly away from the tooth and also controls the moisture in the area. FIGURE 8.7. (Courtesy of Ultradent, Inc., South Jordan, UT.). Therefore, ZOE materials smell and taste like cloves. Define impression compound. The different-shaped trays are designed to take impressions of different oral conditions: edentulous mouths, partially edentulous mouths, and mouths with a full complement of teeth. These replicas are called casts. Wax comes in many forms (sticks, strips, tubes, etc.).
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