The goal of impression making is to produce an accurate impression that can yield a cast or die that reproduces the surface details and precise shape of the original tissue as closely as possible. Before the test began, the jig was adjusted so that the specimen was neither in compression nor in tension. PVS impression materials can make details of even 1 to 2μm. Flexitime showed the highest Sy values among the LB products (56.57 mm) and the lowest values among the HB materials (9.43 mm). A dental impression is a negative imprint of hard (teeth) and soft tissues in the mouth from which a positive reproduction (cast or model) can be formed. This allowed for the production of up to three samples at the same time (Figure 3(b)). High USb and Ys values represent positive features, as they indicate the ability for the impression material to be considerably stretched or deformed, while clinically overcoming wide undercuts, without undergoing breakage or permanent deformations. 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. University of Michigan School of Dentistry Ann Arbor, Michigan. Mean values and standard deviations for TSb, YS, USb, and Sy were calculated in each group. Although new elastomeric impression materials have been introduced into the market, there are still insufficient data about their mechanical features. Mean values (and standard deviations, SD) recorded for tensile strength at break (TSb), yield strength (YS), ultimate strain at break (USb), and strain at yield point (Sy) in the different experimental groups. PROPERTIES OF IMPRESSION MATERIALS: Accuracy: According to American Dental Association specification number 19, to create exact castings, elastomeric impression materials must be able to reproduce fine detail of 25 μm or less. Hondrum investigated the changes in the properties of nonaqueous elastomeric impression materials over time and on exposure to various environmental conditions. 0000007383 00000 n The elastic properties of these elastomeric impression materials improve with an increase in curing time in the mouth An extra time of 1 or 2 min before removal may … In prosthodontics, impression materials are used to record intraoral structures for the fabrication of definitive restorations. 1993; 21: 297-301 Surface properties of elastomeric impression materials N. Vassilakos and C. Pinheiro Fernandes Department of Prosthetic Dentistry, Centre for Oral Health Sciences, Lund University, Malm Sweden ABSTRACT This study investigated the wettability of commonly used elastomeric impression materials and their gypsum castability. Nevertheless, according to the authors, it is also desirable that the material tears rather than deforms on a critical point such as a margin, as in clinical practice it appears easier to properly judge and consequently discard a torn impression, rather than a deformed one. On the contrary, for PE impression materials, the heavy-body product showed higher USb values than the light-body product (HB: 77.17 mm, LB: 45.68 mm). 2015, Article ID 428286, 8 pages, 2015. https://doi.org/10.1155/2015/428286, 1Department of Oral Rehabilitation, Istituto Stomatologico Italiano, University of Milan, 20122 Milan, Italy, 2Department of Medical, Oral and Biotechnological Sciences, University of Chieti, 66100 Chieti, Italy, 3Department of Life, Health and Environmental Sciences, University of L’Aquila, 67100 L’Aquila, Italy. Polyethers (PE) are composed of a moderately low-molecular-weight polyether, a silica filler, and a plasticizer. The accuracy of these final restorations is highly dependent on the impression materials and techniques utilized. Materials investigated included a polyether impression material, a polysulfide material (light, regular and heavy consistencies) and an addition-reaction However, the viscoelastic rheological properties of impression materials, particularly the time-dependent viscoelastic changes in impression material immediately after tray seating, are unknown. Mean values for tensile strength, yield strength, strain at break, and strain at yield point were calculated. Materials possessing elastomeric properties include both natural and synthetic rubber, urethane, polyurea and polymeric coatings. The impression taken should be highly precise, thus, requiring specific care when manipulatingthese materials. 0000036149 00000 n – However, they are not as accurate as other non aqueous elastomeric materials. 0000007852 00000 n Within the light bodies (LB) that are typically employed in the interproximal/subgingival areas and thus appear more subject to clinical tearing, the best performances in terms of TSb and YS were observed in the Acqu-LB and Exa-LB groups, with Exa-LB conveniently showing a relatively high TSb/YS ratio. However, the viscoelastic rheological properties of impression materials, particularly the time-dependent viscoelastic changes in impression material immediately after tray seating, are unknown. Elastomeric impression materials are in common use. Elastomeric Impression Material Mechanical Properties Detail Reproduction: Impression materials must reproduce the fi nest details of the oral tissues and be able to transfer them accurately to gypsum dies or digital scanners. Comparing the different brands within the same viscosity, Heraeus Kulzer Flexitime and Zhermack Hydrorise showed the highest USb values both among the light bodies (101.25 mm and 90.39 mm, resp.) 0000112465 00000 n Purpose. J Prosthodont Off J Am Coll Prosthodont. The elastic nature of impression materials prevents the use of most hardness tests except for the Shore A, which uses a Shore A durometer whereby the value describes the material elasticity. Moderate rigidity of polyether was also recognized [15]. 0000001930 00000 n 0000006117 00000 n The actual behavior of the MB viscosities proved to be quite unpredictable: despite what one could expect, only for Exa’lence and Affinis, the TSb of the medium body showed an intermediate TSb value between those of the corresponding HB and LB viscosities. The strain at yield point indicates the amount of undercut an impression material can overcome without permanent elastic deformation. Sign up here as a reviewer to help fast-track new submissions. An Impression material is the substance used to achieve a negative reproduction of the soft and hard tissues of the oral cavity, to attain the perfect reproduction of the Oral cavity the Impression material needs to have certain ideal Properties to achieve the perfect impression or reproduction of the patients oral cavity and tooth or teeth in question. The accuracy of these final restorations is highly dependent on the impression materials and techniques utilized. For each impression material, 10 dumbbell-shaped specimens were fabricated (), according to the design described as type 1 and type C, respectively, within the ISO 37:2005 and within the ASTM.D412 specifications (see Figure 1 and Table 2). Since VPSs do not produce a volatile byproduct during polymerization, very small dimensional changes occur on setting [7]. Although new elastomeric impression materials have been introduced into the market, there are still insufficient data about their mechanical features. Where subgingival margins are concerned, the selection of a more rigid material with higher yield strength can be an important clinical criterion. Three areas of each specimen narrow portion were measured and checked three times to accurately confirm their width and thickness, which were averaged to obtain a final measurement. 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. Hardness is basically the resistance of a material to permanent surface indentation. Four types of elastomeric impression materials are available for crowns and fixed partial denture impres- sions : addition silicone, condensation silicone, polysul- fide and polyether (18,21,28). Surface properties and castability of elastomeric impression materials after plasma cleaning An impression material sustains some deformation as it is removed from the mouth but it must rebound to its pre- removal dimensions. The selective impression technique is recommended for removable prosthodontics. Future researches are necessary to simulate the clinical oral behavior of impression materials. The Impression materials are classified based on their function – Dentulous or Edentulous Impression, based on their type – Elastic or Rigid etc. Walker at al. 0000026653 00000 n However, VPS materials are recently being labeled as hydrophilic due to the addition of extrinsic surfactants [8, 9]. Polysulfide 3. 18—2004,” Council on Dental Materials, Instruments, and Equipment. 0000009928 00000 n In prosthodontics, impression materials are used to record intraoral structures for the fabrication of definitive restorations. What is an Elastomer? the actual impression material is the most influential [11,18]. Apart from the chemical nature of the material, the primary method of classification is according to consistency. 0000025442 00000 n [20] recently suggested that high impression material rigidity and hardness are not predictors of impression removal difficulty. Comparing the different viscosities of products from the same manufacturer, heavy-body materials showed higher tensile strength values than the light bodies; such a difference proved to be not statistically significant () for Aquasil (HB: 5.1 MPa, LB: 4.98 MPa—) and Impregum (HB: 1.49 MPa, LB: 1.47 MPa—). The impression taken should be highly precise, thus, requiring specific care when manipulatingthese materials. Hondrum[15] investigated the changes in the properties of nonaqueous elastomeric impression materials over time and on exposure to various environmental conditions. It is made by placing an appropriate material in a stock or custom dental impression tray which is designed to roughly fit over the dental arches. Tensile strength at break is the maximum tensile stress applied in stretching a specimen to rupture [9]. Recently, vinylpolyether silicone (VPES) products were commercially introduced. Among VPSs, Aquasil exhibited the highest TSb value (5.1 MPa) compared to all other materials tested, irrespective of the viscosity. An explanation for the recorded high standard deviations might be found in the testing apparatus: during tensile loading of samples, when testing tear energy, the tear could deviate from the central axis of the specimen and the observed elongation might not be accurate. A performing material should display high yield strength and adequate elastic recovery and should require the expenditure of large amounts of energy to initiate and propagate tearing. Hondrum[15] investigated the changes in the properties of nonaqueous elastomeric impression materials over time and on exposure to various environmental conditions. The selective impression technique is recommended for removable prosthodontics. A timer was started immediately after the impression material was first dispensed into the mold. Vinylpolysiloxanes consistently showed higher tensile strength values than polyethers. Creep compliance measurements were shown to be effective in characterizing the elastic, retarded elastic, and viscous properties of polysulphide, silicone, and polyether impression materials. A study of the “thixotropic” property of elastomeric impression materials. 19 for Non-Aqueous, Elastomeric Dental Impression Materials. A classification and some properties of these materials is given in the ISO Standard for Dental Elastomeric Impression Materials (ISO 4823). 0000031199 00000 n 0000146873 00000 n Mechanical Properties of Elastomeric Impression Materials: An In Vitro Comparison By Dino Re, Francesco De Angelis, Gabriele Augusti, Davide Augusti, Sergio Caputi, Maurizio D’Amario and … Revised ANSI/ADA Specification no. Nevertheless, impressions are clinically subjected to tensile forces immediately after the manufacturer’s setting time. Mean values and standard deviations achieved for TSb, YS, USb, and Sy are shown in Table 3, which also summarizes the results of the one-way ANOVA and Tukey’s tests. VPSs consistently showed higher tensile strength at brake (TSb) values than PEs. Lu et al. In addition, the changes in viscoelastic properties of these materials during setting are discussed. Walker MP, Rondeau M, Petrie C, Tasca A, Williams K. Surface quality and long-term dimensional stability of current elastomeric impression materials after disinfection. As a consequence, in the present study, tests were performed immediately following the setting time, which seems a clinically relevant method. Properties of Elastomeric Impression Materials. 0000008532 00000 n Specimens that were not in accordance with the dimensions specified within the ISO 37:2005 (Table 2) were discarded; entirely new specimens were subsequently prepared. 0000016718 00000 n Elastomeric Impression Material Mechanical Properties Detail Reproduction: Impression materials must reproduce the fi nest details of the oral tissues and be able to transfer them accurately to gypsum dies or digital scanners. A method of measuring torsional shear modulus and rigidity of elastomeric impression materials has been developed and is described. The table provides data on three of the most important mechanical properties for four elastomeric impression materials. The TSb (MPa) was calculated using the equationwhile the YS (MPa) was obtained from the force recorded at the yield point using the equationwhere Fb (N) is the force recorded at brake, Fy (N) is the force recorded at yield, (mm) is the width of the narrow portion of the die, and (mm) is the thickness of the test length. The material located at or close to undercut areas could permanently deform on removal. Purpose. – With proper handling, polysulfide impression materials can be used for inlays, crowns, and bridges. Tolley LG, Craig RG. In this study, we examined the rheological properties of elastomeric impression materials, both before and during setting, to assess the clinical significance of certain key characteristics such as viscosity, pseudo-plasticity, and the rate of development of elasticity. The value is provided with two numbers: one represents the hardness at 90 seconds after removal from the mouth; the other at 2 hours. Beside Affinis group, all the other tested VPSs showed slightly increased but statistically similar YS values when the HBs were compared with the corresponding LBs produced by the same manufacturer. Indeed, the ideal impression material should exhibit maximum energy absorption without tearing and with minimal distortion. As a result, comparison between different impression materials using the available literature data still appears quite difficult [15, 17]. The tensile properties of 17 hydrophilic impression materials with different consistencies were compared. The level of was set at 0.05 in all tests. of the material; for example material E is much nearer to perfect elasticity than material A although the latter is more flexible. 0000015634 00000 n 0000028396 00000 n The yield point was defined according to the 0.2% offset method, by estimating a 0.2% permanent deformation as a clinically significant deformation limit. ... measurements showed that the polysulphide materials were the most viscoelastic followed by silicone and polyether impression materials. This … It is also apparent from Figs 2 and 3 that some materials such as the polysulphides have substantial changes in properties with time after setting compared to the silicone or polyether impression materials. Mentioning: 6 - Purpose. 1993; 21: 297-301 297 Surface properties of elastomeric impression materials N. Vassilakos Department and … While for Exa-LB the TSb/YS ratio was relatively high (0.669), for Acqu-LB the TSb/YS ratio was the lowest one observed and could not overcome 0.396. There are 4 groups of elastomers; polysulfide, condensation silicone, addition silicone and polyether; each differ in their setting mechanism and their physical and chemical properties. Condensation Silicones – Condensation silicone impression materials were the next elastomeric impr ession material to be developed for dentistry. The USb (mm) and the Sy (mm) were recorded. However, there is little information on the mechanical properties such as tensile and yield strengths of new elastomeric impression materials. From the present results, the TSb/YS ratios ranged between 0.396 (Acqu-LB group) and 0.764 (Hydro-MB group). An impression with a sufficiently high elastic limit should not sustain permanent deformation. have found a lower tensile strength of a soft polyether (Impregum, 3M ESPE) compared to two hydrophilic addition silicones (Imprint II, 3M ESPE and Flexitime, Heraeus); the authors also reported higher tear properties and tensile strength of heavy-body materials than light viscosities [9]. The tear of elastomeric materials is a mechanical rupture process initiated and propagated at a site of high stress concentration caused by cut, defect, or localized deformation. Mechanical Properties of Elastomeric Impression Materials: An In Vitro Comparison, Department of Oral Rehabilitation, Istituto Stomatologico Italiano, University of Milan, 20122 Milan, Italy, Department of Medical, Oral and Biotechnological Sciences, University of Chieti, 66100 Chieti, Italy, Department of Life, Health and Environmental Sciences, University of L’Aquila, 67100 L’Aquila, Italy, Affinis System Heavy Body 360 (dynamic mix), Coltène/Whaledent AG, Altstätten, Switzerland, Flexitime DYNAMIX Heavy Tray (dynamic mix), Exa’lence Regular Set Heavy (dynamic mix), Zhermack SpA, Badia Polesine (RO), Italy, Impregum Garant Duosoft L (syringe automix). Rheological properties of elastomeric impression materials for selective pressure impression technique. 0000036019 00000 n 0000003908 00000 n Author information: (1)Department of Oral Function and Rehabilitation, Nihon University School of Dentistry at Matsudo, Japan Tolley LG, Craig RG. As a general trend, the material that is more rigid also possesses higher yield strength [15]. Among the light bodies, the highest yield strength was achieved by the hybrid vinylpolyether silicone (2.70 MPa). The strain at yield point (Sy) of Exa-LB was not statistically different from the highest Sy values, which were yielded in the present study by the Flexitime and Hydrorise light bodies. Viscoelastic properties of elastomeric impression materials: polysulphide, silicone and polyether rubbers. Results. The choice of an impression material for particular applications should be based on the specific property data rather than on the type and class of the elastomer. Only for PE impression materials the heavy body showed higher Sy values than the light body (HB: 48.23 mm, LB: 18.56 mm). In general, the qualities of addition silicones and polyethers were superior to polysulfides and condensation silicones. . The amount of permanent deformation is related to the concentration of elastically effective network strands and the degree of cross-linking [14, 21]. 0000006651 00000 n The ANSI/ADA standard specifies that tear strength specimens of dental elastomeric impression materials should be tested 1 hour following polymerization [25]. 0000031677 00000 n The difficulty of removing impressions made of the putty or the polyether, and the increased risk of die breakage could be associated with the higher rigidity of these materials. Four silicone impression materials… Data were subjected to a one-way analysis of variance (ANOVA) and Tukey’s HSD test for multiple comparisons. 0000011326 00000 n This chapter addresses the manipulation of addition silicone (polyvinylsiloxanes or polysiloxanes) impression material. After complete setting and mold removal, any excess impression material residue was carefully trimmed away with a razor blade. When an impression is removed from the mouth, the material must withstand the forces associated with separating the impression from the tooth and its surrounding tissues. The specimens were loaded in tension until failure (Figure 5) with a crosshead speed of 250 mm/minute. Revised American Dental Association Specification No. Materials and Methods. Viscoelastic properties of elastomeric impression materials: polysulphide, silicone and polyether rubbers. 0000030913 00000 n From the standpoint of clinical application, materials with high tensile strength are not necessarily considered to be superior to the materials with low tensile strength. Materials and Methods Table 1 gives details of the materials used in this study. The clinical tear performance of a material also appears crucial [15, 16]: it involves complex interactions between polymer and fillers, flow to a particular film thickness, release properties from tooth and soft tissue, presence of internal and surface defects, and rate of impression withdrawal. Injection of the impression materials through dedicated, commercially available tips (a) allowed the production of up to three samples at the same time (b). It is also apparent from Figs 2 and 3 that some materials such as the polysulphides All elastomeric impression materials experience shrinkage during setting. The tensile properties of 17 hydrophilic impression materials with different consistencies were compared. 0000002021 00000 n Refined dumbbell test specimens ready for the test (Instron machine). Dino Re, Francesco De Angelis, Gabriele Augusti, Davide Augusti, Sergio Caputi, Maurizio D’Amario, Camillo D’Arcangelo, "Mechanical Properties of Elastomeric Impression Materials: An In Vitro Comparison", International Journal of Dentistry, vol. Surface properties and castability of elastomeric impression materials after plasma cleaning 2007 Oct;16(5):343–51. L. G. TOLLEY. Adequate clinical protocols [1, 2] based on careful tooth preparations and standardized luting or cementation procedures [3, 4] proved to be crucial. 0000025029 00000 n 0000033223 00000 n 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. Int J Prosthodont 1994; 7:155- 8. Among the light bodies investigated in the present study, both Acqu-LB and Exa-LB showed relatively high mean values for both tensile and yield strength. 0000011224 00000 n Many studies [9, 14, 15, 20, 22–24] on tear strength have been carried out so far; however, standardized test methods have not been established. Materials with different consistencies (heavy-, medium-, and light-body) were investigated. The tensile properties of 17 hydrophilic impression materials with different consistencies were compared. The purpose of this study was to compare tensile properties (tensile strength at break, yield strength, ultimate strain at break, and strain at yield point) of 17 hydrophilic elastomeric impression materials. Copyright © 2015 Dino Re et al. Clinically relevant mechanical properties of elastomeric impression materials. Introduction Impressions of the teeth and oral soft tissues are frequently obtained during dental treatment.1 Elastomeric impression materials have been used with good clinical results for all kinds of restorations because of their ELASTOMERIC IMPRESSION MATERIALS IN PROSTHODONTICS KEYF properties approaching these requirements fall into two groups, the rubber-like elastomers and the hydrocol-loids (9,28). The success rate of prosthetic tasks relies on different factors. 0000020643 00000 n Concerning the ultimate strain at break (USb), statistical analysis showed that heavy-body VPSs had significantly reduced mean values compared to the corresponding light bodies, with the exception of Affinis (HB: 47.19 mm, LB: 47.55 mm) and Aquasil (HB: 34.53 mm, LB: 45.88 mm). Statistical analysis showed significant differences in the tensile strengths of different products, supporting findings in the literature [9, 19]. VPS are intrinsically hydrophobic in nature, which can result in voids at the margin of the tooth preparation in the impression and bubbles in gypsum casts. In this study, we examined the rheological properties of elastomeric impression materials, both before and during setting, to assess the clinical significance of certain key characteristics such as viscosity, pseudo-plasticity, and the rate of development of elasticity. Purpose. Materials investigated included a polyether impression material, a polysulfide material (light, regular and heavy consistencies) and an addition-reaction silicone material (light, regular, heavy and putty consistencies). The actual extent of the dimensions indicated by uppercase letters is specified in Table. The polymerized material have to maintain its elasticity under stresses created, for instance, when it flexes over tissue undercuts. Chai J, Pang I. Chai et al.—in a study comparing a wide range of materials of different brands and categories—reported a high strain tolerance of the VPS impression materials that might facilitate their removal without distortion from appreciable tissue undercuts [15]. }, author={M. Kawara and Masatoshi Iwasaki and Y. Iwata and Yoshihiro Komoda and … 0000002284 00000 n 0000024640 00000 n 0000002483 00000 n 12 vinylpolysiloxane, 2 polyether, and 3 hybrid vinylpolyether silicone-based impression materials were tested. The selective impression technique is recommended for removable prosthodontics. 0000033493 00000 n Polyethers showed the lowest tensile (1.44 MPa) and yield (0.94 MPa) strengths, regardless of the viscosity. Meanwhile, the dimensions of the impression should remain stable during the production of dies or casts. With viscoelastic materials, such as dental impression materials, deformation also depends on temperature and rate of stress [17]. The ultimate strain at break (USb) mean value experimentally observed for the VPES material in the Exa-HB group was numerically higher than the USb mean values recorded for all the other heavy-body VPSs. The specimens were prepared at standard laboratory conditions (23°C ± 1°C) by dispensing impression material from the cartridge into the already assembled steel mold, through lateral apertures specifically designed for placing the differently shaped cartridge tips. 0000028653 00000 n shows the properties of different elastomeric impression materials. This can be probably seen as a further clinical advantage of the new VPES hybrid material. However, the viscoelastic rheological properties of impression materials, particularly the time-dependent viscoelastic changes in impression material immediately after tray seating, are unknown. Heavy-body materials showed higher tensile strength than the light bodies from the same manufacturer. properties of impression material and the time immediately after seating a tray with the impression material into the mouth (the initial stage of seating), are considered to be most important [14,15]; however, there have been few reports on time-dependent changes due to differences in impression materials. The lower plate contained three dumbbell-shaped perforations so that, once assembled with the upper plate, three paths for the injection of the impression materials were made available (Figures 2(c) and 3(a)). 0000004442 00000 n PVS impression materials can … Elastomers are polymers characterized by highly flexible kinked segments that allow freedom of movement. The selective impression technique is recommended for removable prosthodontics. Heavy-body VPSs generally showed higher TSb values than the light bodies from the same manufacturer. Because of the complexities of integrating and measuring these properties, laboratory tests evaluating the propagation energy of a tear have been employed as common ways to evaluate elastic dental materials [9, 17]. Although new elastomeric impression materials have been introduced into the market, there are still insufficient data about their mechanical features. Example of a specimen loaded in tension until failure. Adequate mechanical properties ensure that the impression material can withstand various stresses upon removal, while maintaining dimensional stability and integrity. It has been defined as the property that indicates the ability of an impression material to withstand tearing in thin interproximal and crevicular areas [18]. We will be providing unlimited waivers of publication charges for accepted research articles as well as case reports and case series related to COVID-19. A classification and some properties of these materials is given in the ISO Standard for Dental Elastomeric Impression Materials (ISO 4823). tray material of six elastomeric impression materials. Stainless steel split mold used to produce the dumbbell test specimens: lower (a) and upper (b) plates. Thus, when we consider the pressure during impression taking for dentures, the viscoelastic rheological properties of impression material and the time immediately after seating a tray with the impression material Values than PEs dimensions for dumbbell test specimens according to type 1 of most. Renders it inaccurate [ 15 ] without permanent elastic deformation been developed and is described silicone impression:. Of the impression from the chemical nature of the viscosity for four elastomeric impression.... Most viscoelastic followed by silicone and polyether rubbers and discarded to ensure mixing. 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Polyethers ( PE ) are composed of a fixed compressive strain and the Sy ( mm were. Is lower with polyvinyl siloxane materials compared to LB viscosities due to the addition of surfactants. The viscosity simulate the clinical oral behavior of the elastomer upper ( b )! Hb viscosity of the segments past the point where elastic recovery and acceptable flexibility on removal was.! Study tools differences in mechanical properties for four elastomeric impression materials ( ISO )... ’ ability to withstand stresses under various clinical situations a condensation reaction little on! Of dental elastomeric impression materials: polysulphide, silicone and polyether impression materials have been into! Well as case reports and case series related to COVID-19 ensure that the impression material should exhibit mechanical... And/Or type C of ASTM.D412 specifications no significant differences in the ISO 37:2005 specifications and/or type C of ASTM.D412.! Ys with the claim of very high elastic recovery and acceptable flexibility on removal of viscosity. Marketed rubber impression materials has been developed and is described close to areas... Labeled as hydrophilic due to the addition of extrinsic surfactants [ 8, 9.... Changes occur on setting [ 7 ] of elastomer products were commercially introduced intraoral for... = light body also depends on temperature and rate of stress [ 17 ] in chapter 8, impression were! Vpes hybrid material result, comparison between different impression materials material to be developed for Dentistry material is the sult... By cut, defect, or localized deformation findings in the properties of elastomeric impression materials have been into. Materials: polysulphide, silicone and polyether impression materials discussed in chapter 8, impression material should tested!, Aquasil exhibited the highest TSb value ( 5.1 MPa ) strengths, regardless of ISO! As other non aqueous elastomeric materials is a mechanical rupture process initiatedandpropagatedatasiteofhighstressconcentration caused by,. On temperature and rate of stress [ 17 ] from the mouth [ 6.! The tray material was examined of removal from the chemical nature of the material located at or close to areas! New VPES hybrid material four types properties of elastomeric impression materials impression materials: Till now the impression.