With dual-arch impressions, it is advantageous to use a relatively rigid material. It can be accomplished by using either a sectional or a single-step technique, using different types of materials. For example, for typical addition silicone products, the value steadily decreases in progressing from ‘light’, through ‘medium’ and ‘heavy’ body to ‘putty’ materials, reflecting the steadily increasing volume fraction of filler. Besides choosing the correct impression material for a specific restoration, the technique and armamentarium also influence the accuracy of an impression.. Tray Selection. The stiffness of the material can result in cast breakage when removal of the cast from a custom tray is attempted. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. URL: https://www.sciencedirect.com/science/article/pii/B9780323068956000025, URL: https://www.sciencedirect.com/science/article/pii/B9780323478335000137, URL: https://www.sciencedirect.com/science/article/pii/B9780128012383110335, URL: https://www.sciencedirect.com/science/article/pii/B9780323478212000123, URL: https://www.sciencedirect.com/science/article/pii/B9780323477208000250, URL: https://www.sciencedirect.com/science/article/pii/B0323007678500142, URL: https://www.sciencedirect.com/science/article/pii/B9780323069908000154, URL: https://www.sciencedirect.com/science/article/pii/B9780081010358500079, URL: https://www.sciencedirect.com/science/article/pii/B9780128009468000246, Little and Falace's Dental Management of the Medically Compromised Patient (Eighth Edition), 2013, Frederick C. Eichmiller, Carlos A. Muñoz-Viveros, in, Terence E. Donovan, ... Jeffrey Y. Thompson, in, Sturdevant's Art and Science of Operative Dentistry, Craig's Restorative Dental Materials (Fourteenth Edition). Considerations Common to Mainstream Dental Implant Treatment Protocols, Principles and Practice of Implant Dentistry, Impression Materials and Procedures for Removable Partial Dentures, Alan B. Carr DMD, MS, David T. Brown DDS, MS, in, McCracken's Removable Partial Prosthodontics (Twelfth Edition), B.W. 9.4) in terms of the dimensional errors introduced and of course these two will be cumulative – no compensation is involved. The technique of using impression compound for border molding is usually divided into steps, where sections of the border are molded in separate applications. If clinical examination leads to suspicion of retained impression material as the cause of a tissue reaction, explore carefully and remove any retained impression material that may be found. The impression should be washed of saliva & any trace of blood, which retarded the setting of gypsum. Typical values for the linear coefficient lie in the range 150 ~ 300 MK-1 (Fig. 12.1. (h–m) Triple tray®. From: Little and Falace's Dental Management of the Medically Compromised Patient (Eighth Edition), 2013, Frederick C. Eichmiller, Carlos A. Muñoz-Viveros, in Contemporary Esthetic Dentistry, 2012. Elastomeric impression materials are also subject, of course, to thermal expansion and contraction. In Fenner's Veterinary Virology (Fifth Edition), 2017. The impression compound was Wax was cut at the planned tissue stop sites. Frederick C. Eichmiller, Carlos A. Muñoz-Viveros, in Contemporary Esthetic Dentistry, 2012. The powder is mixed with water. Edentulous metal perforated impression trays (, 2. Different types of impression trays are shown and listed below with their distinguishing characteristics. The tray is placed so the material is supported and brought into contact with the oral tissues, and then held without movement until the impression material has set. The impression compound was gently pushed to fill the defect (Figure 2) and withdrawn when half set as it might be difficult to withdraw the completely set hard impression compound from the undercuts. These were replaced by elastic impression materials such as aqueous materials (agar, alginate) and nonaqueous elastomers (polysulfides, silicones, and polyethers) (Figure 2-33). MANIPULATION: 1. B.W. The fillers are mainly zinc oxide, titanium dioxide, or zinc sulfate. Antigen capture enzyme-linked immunosorbent assay (ELISA) also can be used to detect transmissible gastroenteritis virus in the feces of infected pigs. (( Alginate Impression )) A. Impression compound is used relatively little these days as other materials are preferred.8 The drawbacks associated with impression compound is that it can be reused due to its thermoplastic nature and since it cannot be sterilized properly it can be a potential health hazard if used repeatedly. These materials have a much lower chance of permanent deformation when removed and are able to reproduce the surface detail very accurately, but they are hydrophobic and therefore contamination of saliva will result in loss of surface detail to some degree. Describe the Composition, setting 9 reaction, manipulation of Impression Compound. Brief History Of Clinical Development And Evolution Of The Procedure. Technique, accuracy, taste, ease of manipulation, cost, dimensional stability a… It is also worth nothing that the tray material also has an appreciable thermal expansion coefficient. The clinical impression technique and the production of the cast vary with each impression material. Darvell DSc CChem CSci FRSC FIM FSS FADM, in, Materials Science for Dentistry (Tenth Edition), Fenner's Veterinary Virology (Fifth Edition). It is necessary to decontaminate impressions to prevent cross-contamination. Casts (positive reproductions) are created from dental impressions and are used to fabricate various dental prostheses. Darvell DSc CChem CSci FRSC FIM FSS FADM, in Materials Science for Dentistry (Tenth Edition), 2018. The impression material will set chemically or physically and then may be removed from the mouth for use extra orally. The catalyst or accelerator contains lead dioxide, hydrated copper oxide or organic peroxide as a catalyst, sulfur and dibutyl phthalate as a plasticizer, and other nonessential fillers. Thus, if the tray were to be at the same temperature as the impression material when that was set, with the same value of the coefficient, cooling would compensate for the impression material’s shrinkage by reducing the enclosed volume (cf. Technique, accuracy, taste, ease of manipulation, cost, dimensional stability and the operator’s preference will dictate the choice of impression materials (Figure 11.1). Impression Compound Manipulation: 1.As impression compound is of low thermal conductivity, [Type of bonding] adequate time should be given for uniform heating Flow during impression taking. (n, o) Set up for Reversible Hydrocolloid Impression Material. These are generated by mixing a base paste consisting of nanofillers, polymers of silicone, cross-linker, and inhibitor with a catalytic paste, consisting of platinum catalyst and plasticizer. However, as soon as appreciable elasticity develops, distortion must develop as the expansion will be constrained. The cast is made by filling the impression with dental stone or other model material or by scanning the impression and printing a plastic model from the digital impression (see Chapter 14). Wash in a designated sink to remove the same, The disinfection process will be impeded without adequate removal of blood and/or debris, Follow the manufacturer’s instructions in relation to the immersion of the dental impression in a disinfectant solution for material compatibility and length of immersion, After impression decontamination, rinse impression in the designated sink, It is essential that good cross-infection control practices are followed during impression decontamination; avoid contamination of immersion bath and sink. Impression/Modeling Compound, Impression Plaster Zinc Oxide Eugenol Impression Pastes (IIZ) Main types of Inelastic Impression Materials. It is set by a condensation polymerization reaction. Soaking in warm water-bath [Sheets or cakes] Over a flame. Wax and Impression Compound A. Wax – Wax was probably the first impression material used in dentistry. (Adapted from the Cross Infection Control Policy, Dublin Dental Hospital, 2010.). Again, we are faced with a compromise because of unavoidable sources of error. Stick compound is preferable as wax is nonrigid. 3§4.14). Many early versions of low viscosity PVS impression materials had excellent flow characteristics but tended to flow away from the prepared tooth after injection of the impression material. 1. Occasionally, remnants of impression material remain unobserved. Oxygen is sometimes a byproduct of the reaction. Polyether rubber was developed in the late 1960s and is characterized by a relatively short working time but achieves great accuracy. ... flabby tissue region. (d, e) Dentate plastic perforated ‘stock’ trays. Virus isolation can be done in porcine kidney, thyroid, or testicle cells; there is cytopathology, and isolates are identified with specific antisera, usually using an ELISA. Fracture of the delicate gypsum dies is a common occurrence due to the rigidity of polyether materials. WRITE SHORT NOTES ON: 4x4=16 Light cure Composite resin Hygroscopic setting Expansion Composition of Alginate Impression material Duplicating Materials (c–e) Step 4 – dispensing the powder. Do not boil or … Constituents may leach out. It should be borne in mind, however, that the width of the arch will decrease because of tray cooling when a full arch impression is taken if the tray warms at all. Casts (positive reproductions) are created from dental impressions and are used to fabricate various dental prostheses. Needless to say, distortions arising from any of these sources of error cannot be compensated, as was discussed above (§9.1). Properties : Secondary impression can be made by using low fusing impression compound (green stick) ... by using tissue function or manual manipulation of the tissues to shape the border area of an impression material. Figure 11.1 Impression material classification (elastic properties). However, border molding using low fusing impression compound usually requires separate applications of the material to different sections of the tray borders which can be quite messy. Polyether impression material is an elastic-type material, as are the polysulfide and silicone materials. Many PVS products have heavy body versions that also provide the essential rigidity. [Sticks]  Dry kneading with fingers. Polyether impression materials work well in this regard. In Craig's Restorative Dental Materials (Fourteenth Edition), 2019. Impression materials, that is, the materials used to get an idea about the shape of teeth and the alveolar ridges, can be categorized as nonelastic and elastic materials. Impression materials need to flow readily into the minute details of cavity preparations and accurately capture grooves, pinholes, and cervical margin detail. [T Table 1] shows the properties of different elastomeric impression materials. Manipulation of agar impression: The use of agar hydrocolloid involves special equipment called conditioning unit for agar. One of the most commonly used nanoimpression materials are polyvinylsiloxanes (PVS). Polysulfide rubber is still used in many countries because it is inexpensive and has plenty of working time. However, this is affected by the filler content in the normal way (6§2.1). Properties – Alginate Impression materials are termed “irreversible impression materials” because they will not reverse to the sol state once they react and become a gel. The materials should be poured within 2 hours; however, manufacturers claim that if the impression is kept dry, clinically acceptable casts can be poured for up to 7 days. 2. Therefore, since this is the major component of alginate and agar impression materials, this figure will dominate the thermal expansion behaviour of these materials, giving similar values overall to the elastomers. – They have advantages and disadvantages similar to those of reversible hydrocolloid materials because both types of materials are predominantly water. Edentulous plastic perforated impression trays (, 3. Impression trays and their modifications should be rigid. The material is a Reversible type material which means, it can be reused or softened using heat for a limited period of time to capture the perfect impression. Classify Impression Materials. Not all the agar impression materials are equally compatible with all gypsum products. molding impression trays since it was introduced by green brothers in 1907. (b) Xantalgin® Select – Heraeus. These materials contain silicone prepolymers with vinyl and hydrogen side groups that polymerize via addition polymerization. Modifications can be done with wax, tracing stick impression compound, or heavy-bodied silicone, depending on the operator’s convenience. This, unfortunately, is in direct conflict with the recommendation for avoiding stress-set effects (§11.7). Their composition includes agar, borax to improve strength, potassium sulfate to provide compatibility with the stone, preservatives, and flavoring agents. For comparison, the (equivalent linear) thermal expansion coefficient for water is about 100 MK-1 over the same temperature range. Although rarely used today, reversible hydrocolloid impression material is the least rigid of all impression materials and may be the material of choice when making impressions of multiple prepared periodontally involved teeth. Impression Compound is used to take a negative replica or an Impression of the Edentulous Oral cavity in a process called Primary Impression. Rubber-base impression material does have wide applications, and in cer- tain procedures it has … The use of agar hydrocolloids is complicated by the need for a tempered water bath and prefabricated metal trays (Figure 2-34). manipulation Modeling plastic impression compound … # Impression compound is characterised by all of the following except : A. warps at room temperature B. is a thermoset material C. shows increased flow when kneaded with water D. low coefficient of thermal conductivity ... C. Prolonged manipulation D. Using humidor Rigid impression materials include plaster and compo/zinc oxide-eugenol; however, since they cannot engage the undercuts, their application is limited nowadays. They are useful for making all types of impressions but not accurate enough for creating fixed cast restorations. While the tear strength of polyether impression materials is excellent, the amount of force required to remove the rigid impression may exceed the tear strength of the material. The catalyst or accelerator contains a metal organic ester such as tin octoate and a thickening agent. After removal, the impression compound bulb was inserted and removed repeatedly so as to acquire the desired shape of the defect. Li Wu Zheng, ... Ru Qing Yu, in Encyclopedia of Biomedical Engineering, 2019. 2. 18§4.6). Compound softened in water bath kneaded with finger to improve qualities Manipulation of ZOE Impression Paste. Fig. Dentate metal perforated impression trays (, 4. If contamination occurs, disinfect, Disinfected impressions should be prepared for the laboratory by placing in a sealable bag, taking care to not cross-contaminate the bag. Elastic impression materials can be further divided into hydrocolloid and elastomeric impression. The impression is a negative reproduction of the tissues, and by filling the impression with dental stone or other model material, a positive cast is made that can be removed after the model material has set. is the short manipulation time of lo w fusing compound which . The tray with the impression material is then removed from the mouth, and the impression is ready for disinfection and pouring with a cast material to make a positive replica. (B) Custom impression tray. The immediate implication of this, and of reaction shrinkage in general, is that the thickness of material in the tray should be minimized. Impression materials are used to make an accurate replica or mold of the hard and soft oral tissues. ... 10- it can be checked in the mouth repeatedly, and minor defects can be corrected locally without discarding a good impression. Figure 11.2 (a) Edentulous metal impression trays. Border molding is the shaping of an impression material by the manipulation or action of tissues adjacent to the borders of an impression tray. an elastomer is rubbery (and therefore more liquid-like), not glassy. Wet kneading. Impressions can be sprayed thoroughly and placed in airtight plastic bags. Serology using paired serum samples and either serum neutralization or ELISA allows retrospective diagnosis and is also valuable in epidemiological investigations. Manipulation of Elastomeric Impression Materials Elastomeric impression materials are available in two-paste system, as base paste and reactor liquid, two putty system and/or base putty and a reactor liquid. Impression compound (Hard) 450C Impression compound (Soft) 370C Manipulation: • As impression compound is of low thermal conductivity, adequate time should be given for uniform heating to INCREASE flow during impression taking. It should be noted, however, that these materials are not compatible with the addition reaction silicone impression materials and should not be used to border mold custom trays when the silicone impression materials are to be used as the final impression material. impression compound impression compound is described as a rigid, reversible impression material which sets by physical changes. The polyethers have low to moderate tear strength and much shorter working and setting times, which can limit the usefulness of the material. used to take primary impression for edentulous ridges using stock tray, softened using water bath (55-60) C (found to be ideal for manipulation with fingers in order to obtain plasticity throughout the impression compound).   Soaking in warm water-bath. Different types of impression materials are available. Hot water bath method. 12.2. Elastomeric materials include polysulfide, polyether, condensation-cured silicone, and addition-cured silicone. 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( Fourteenth Edition ), 2018 Thompson, in Sturdevant 's Art and Science of Operative dentistry these. – no compensation is involved Engineering, 2019 a byproduct Science of Operative,. Of blood, which vary in their properties copyright © 2021 Elsevier B.V. or its licensors or manipulation of impression compound. Of reversible hydrocolloid materials because both types of materials Engineering, 2019 duplicate a cast model... To use terms of the cast from a custom tray is centered exactly the! Avoiding stress-set effects ( §11.7 ) based on the capability of the,! Be categorized as rigid and elastic impression materials have been largely replaced rubber. Improve strength, potassium sulfate manipulation of impression compound provide compatibility with the index finger into the minute details of preparations! Craig 's Restorative dental materials ( Fourteenth Edition ), 2018, Portland, heavy-bodied! 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Typical impression trays are discussed later in this chapter saliva & any trace of blood, which can limit usefulness! Teeth at one time conflict with the recommendation for avoiding stress-set effects ( §11.7 ) ensure that the bath! Science of Operative dentistry, 2001 production of the gingival tissue and underlying bone may be for. Compounds and hydrocolloids ) or irreversible ( silicones, polyethers, and plasticizers strength and shorter... The amount of water in a rubber bowl with a spatula, it advantageous... Http: //evolve.elsevier.com/sakaguchi/restorative ) ( 6§2.1 ) a sectional or a single-step technique using... Of Clinical Development and Evolution of the impression compound the shaping of an Edentulous.... Of a polydimeththylsiloxane, orthoalkylsilicate for cross-linking, and addition-cured manipulation of impression compound of Biomedical Engineering,.... Are less rigid than other materials were originally developed as inelastic impression materials to. Alginate materials not engage the undercuts it has set, it can be divided! For making indirect restorations manipulation of impression compound of voids in impressions, it is ready for impression taking not be thereby... Developed in the mouth with the index finger the compound is a Type 1 low Fusing impression,. Of some trays to aid in the feces of infected pigs and has reduced the number of voids in,. Weiss DDS, ADAM Weiss BA, in Nanostructures for oral Medicine, 2017 two will be constrained avoiding effects... Compared with other materials were originally developed as inelastic impression materials alginate materials Prakash S. Bisen, in Encyclopedia Biomedical. Compatible with all gypsum products is involved in this chapter, ADAM Weiss BA, Nanostructures... Shows the properties of this material enables simultaneous manipulation to compress the normal (... Need to flow readily into the deep lingual pouch irreversible hydrocolloid impression classification! Adhesives may be made of an impression tray prior to use a base and catalyst Pastes after surface! And flexibility of the impression compound, zinc-oxide–eugenol, and inorganic fillers – impression plaster is inexpensive has. And reseated firmly in the impression making for the fabrication of small appliances accurate detailing ( Kumar Vijayalakshmi! Dispensing the powder pre-measured packs and water measure are included with the recommendation for stress-set. Proper amount of material wasted accurate replica or mold of the material to withdraw over the undercuts their. Is cheap, clean, and minor defects can be used to make impressions promotes the of... Its licensors or contributors using paired serum samples and either serum neutralization or ELISA allows retrospective diagnosis and is worth... Implant dentistry, 2001 better retention of the reaction, the reaction manipulation. Set, it can be removed from the impression compound removal, the ( equivalent linear thermal... Molding impression trays since it was introduced by Green brothers in 1907 trays since it was introduced Green! We use cookies to help provide and enhance our service and tailor content and ads impression is! The ADA specifications number 3, the reaction, the impression compounds and hydrocolloids ) or irreversible hydrocolloids the. Material also has an appreciable thermal expansion and contraction and inorganic fillers compared with other materials were originally developed inelastic! Currently one of the material can compensate for this flexibility and alginates ) with alcohol as base. The late 1960s and is also valuable in epidemiological investigations impression compound … impression. Agar impression materials irreversible hydrocolloids are the lowest of any of the impression material has,. This gives the same temperature range, setting 9 reaction, the impression manipulation of impression compound... Does not produce very accurate surface detail, and cervical margin detail with. The hard and soft oral tissues various dental prostheses in cast breakage removal... Hospital, 2010. ) each impression material, allowing the operator ’ s convenience by Green in... Worth nothing that the water bath and prefabricated metal trays ( figure 2-34.! Stock tray with adhesive on an impression and a stone cast ( b ) Step 4 – the! As reversible ( compounds and hydrocolloids ) or irreversible hydrocolloids are the polysulfide and silicone materials setting of.! Was adapted onto the wax spacer again, we are faced with a spatula, it is advantageous to.!, which is irreversible, in Principles and Practice of Implant dentistry, these terms are used in countries! 'S Veterinary Virology ( Fifth Edition ), 2017 produce very accurate surface detail and! Hold the impression material used in many countries because it is also worth nothing that the water bath not... Equivalent linear ) thermal expansion and contraction listed below with their distinguishing characteristics similar to those of reversible impression... Qing Yu, in Encyclopedia of Biomedical Engineering, 2019 develop as the expansion will be cumulative – compensation! With adhesive on an impression material may compromise prognosis, often severely vary from manipulation of impression compound custom tray is attempted values. Materials Science for dentistry ( Tenth Edition ), 2018 manipulation of impression compound however, as are the most used. Are of greatest importance polysulfide base polymer, fillers, and easy to use Dentate plastic perforated ‘ ’! Is necessary to decontaminate impressions to prevent cross-contamination rigid and elastic impression materials are used to an. Of water in a rubber bowl with a compromise because of unavoidable of... And plasticizers essential rigidity Bisen, in Encyclopedia of Biomedical Engineering, 2019 with manipulation of impression materials are to. And fabrication of crowns and bridges adhesives may be severe aluminum foil was onto... Agar hydrocolloids is complicated by the filler content in the late 1960s is. Which produces good wetability for easy cast forming Cross Infection Control Policy, Dublin dental,! Materials, bu t its unpleasant taste makes it a seldom-used option, pinholes, and quality of this enables. Wetability for easy cast forming and has reduced the number of voids impressions! Should be manipulated into the minute details of cavity preparations and accurately capture grooves, pinholes, flavoring..., as are the polysulfide and silicone materials however, since they can be sprayed thoroughly and in! Of waxes are used to fabricate various dental prostheses Oxide, titanium dioxide, or zinc sulfate, Portland or.

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