Thus, elastic recovery is important in determining the accuracy of an impression material [9]. Walker MP, Rondeau M, Petrie C, Tasca A, Williams K. Surface quality and long-term dimensional stability of current elastomeric impression materials after disinfection. 0000016718 00000 n Heavy-body VPSs generally showed higher TSb values than the light bodies from the same manufacturer. Although new elastomeric impression materials have been introduced into the market, there are still insufficient data about their mechanical features. 0000025442 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 … 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. Purpose. In the present study, statistically significant differences in yield strength between heavy-body VPSs and light-body VPSs were recorded just for Affinis (HB: 2.85 MPa, LB: 1.12 MPa). The Impression materials are classified based on their function – Dentulous or Edentulous Impression, based on their type – Elastic or Rigid etc. However, the viscoelastic rheological properties of impression materials, particularly the time-dependent viscoelastic changes in impression material immediately after tray seating, are unknown. 0000011427 00000 n 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. 0000003207 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. Materials and Methods. Surface properties and castability of elastomeric impression materials after plasma cleaning … 0000027266 00000 n The selective impression technique is recommended for removable prosthodontics. Hondrum[15] investigated the changes in the properties of nonaqueous elastomeric impression materials over time and on exposure to various environmental conditions. 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). 2007 Oct;16(5):343–51. 0000027368 00000 n 0000036149 00000 n tear of elastomeric materials is a mechanical rupture process initiatedandpropagatedatasiteofhighstressconcentration caused by cut, defect, or localized deformation. These elastomeric impression materials are combinations of VPS and PE and are promoted as hydrophilic materials that presumably maintain the stability and characteristics of the parent products [12, 13]. 19 for dental elastomeric impression material. 0000036331 00000 n This may highlight an advantageous peculiarity of the new VPES hybrid material, which showed very high tensile strength values for the light- and medium-body viscosities. As for the TSb, also regarding the yield strength (YS), the HB VPSs showed slightly increased mean values compared to the corresponding LB viscosities; however the differences in yield strength were statistically significant just for Affinis (HB: 2.85 MPa, LB: 1.12 MPa). Elastomer properties include resilience — some elastomeric materials can be stretched repeatedly to twice their length and return to their original shape. Tolley LG, Craig RG. 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). This allowed for the production of up to three samples at the same time (Figure 3(b)). What is an Elastomer? 0000008532 00000 n 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. A classification and some properties of these materials is given in the ISO Standard for Dental Elastomeric Impression Materials (ISO 4823). Rheological properties of elastomeric impression materials for selective pressure impression technique. The yield strength determines the materials’ ability to withstand stress without permanent deformation. 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. The accuracy of these final restorations is highly dependent on the impression materials and techniques utilized. Where subgingival margins are concerned, the selection of a more rigid material with higher yield strength can be an important clinical criterion. Elastomers are polymers characterized by highly flexible kinked segments that allow freedom of movement. Viscoelastic properties of elastomeric impression materials: polysulphide, silicone and polyether rubbers. The complete list of the materials employed is summarized in Table 1 and included 12 VPSs, 2 PEs, and 3 VPESs. In addition, the changes in viscoelastic properties of these materials during setting are discussed. 0000021329 00000 n The purpose of this study was to evaluate the effect of some disinfectant materials with two different techniques on surface detail and dimensional stability of elastomeric impression materials. The upper and the lower plates of the split mold were kept assembled for the whole setting time recommended by each manufacturer and under a constant 5 Kg load. Immediately following preparation (Figure 4), the specimens were secured into the Instron universal testing machine (Instron Corp., Canton, MA, USA), gripping them on both sides by pneumatic clamps at the location of the previously applied benchmarks. 0000031677 00000 n The properties of some recently marketed rubber impression materials were compared with some earlier products. – However, they are not as accurate as other non aqueous elastomeric materials. Accuracy of impression is depends on dimensional stability of impression material, 22 and influenced by a number of factors such as impression technique, impression tray and properties of the impression materials. 0000021063 00000 n Vinylpolysiloxanes (VPSs) (addition silicones) have a moderately low-molecular-weight silicone that contains silane groups. Although new elastomeric impression materials have been introduced into the market, there are still insufficient data about their mechanical features. 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 the actual impression material is the most influential [11,18]. Conclusion. 0000006117 00000 n 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. Adequate mechanical properties ensure that the impression material can withstand various stresses upon removal, while maintaining dimensional stability and integrity. 0000020643 00000 n The tensile properties of 17 hydrophilic impression materials with different consistencies were compared. 0000006651 00000 n 19 for Non-Aqueous, Elastomeric Dental Impression Materials. 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. Surface properties and castability of elastomeric impression materials after plasma cleaning Author information: (1)Department of Oral Function and Rehabilitation, Nihon University School of Dentistry at Matsudo, Japan 0000033977 00000 n Review articles are excluded from this waiver policy. Lu et al. 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). Stainless steel split mold used to produce the dumbbell test specimens: lower (a) and upper (b) plates. Elastomeric impression materials offer high elastic recovery and acceptable flexibility on removal of the impression from the mouth [6]. This chapter addresses the manipulation of addition silicone (polyvinylsiloxanes or polysiloxanes) impression material. 0000004442 00000 n Each uppercase letter relates to the corresponding dimension as indicated in Figure, Shape of dumbbell test specimens produced according to type 1 of the ISO 37:2005 specifications and/or type C of ASTM.D412 specifications. However, we found high coefficient of variations (standard deviation values) for both the yield strength and the strain at yield parameters; such wide variability might influence the statistical significance of results that should be interpreted with caution. 0000035704 00000 n 0000002062 00000 n Among VPSs, Aquasil exhibited the highest TSb value (5.1 MPa) compared to all other materials tested, irrespective of the viscosity. 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. 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 PE impression materials showed the lowest yield strength, regardless of the viscosity. 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. Walker at al. 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.) Tear ,tensile , and yield strengths are important properties for impression materials; they have been investigated by several studies [ , ,,].Luetal.havefoundalowertensilestrengthof Revised American Dental Association Specification No. 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. HB = heavy body; MB = medium body; and LB = light body. 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. PVS impression materials can … 0000016047 00000 n 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. Properties of Elastomeric Impression Materials. – The y are based on silicone rubber, which is com monly used in other industries. The selective impression technique is recommended for removable prosthodontics. Hardness is basically the resistance of a material to permanent surface indentation. Viscoelastic properties of impression materials 125 of the material; for example material E is much nearer to perfect elasticity than material A although the latter is more flexible. Dimensional stability and wettability (resulting in minimal voids and detailed reproduction of intraoral structures) are the main features of PE materials [10, 11]. However, VPS materials are recently being labeled as hydrophilic due to the addition of extrinsic surfactants [8, 9]. This material commonly involves … 1 The amount of shrinkage is lower with polyvinyl siloxane materials compared to polyether materials. Materials investigated included a polyether impression material, a polysulfide material (light, regular and heavy consistencies) and an addition-reaction 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. 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)). 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]. Once the mold was assembled (c), paths for the injection of the impression materials through lateral apertures were made available. h�b``�g``[����d����1G����=30h2I]�ZD�oa=����!,A��.�#��e t�/0>`>"�X°���q���7�[${cv174'�]�4`�¾�����7��y�1. Materials and Methods. Refined dumbbell test specimens ready for the test (Instron machine). [20] recently suggested that high impression material rigidity and hardness are not predictors of impression removal difficulty. 0000005602 00000 n 0000031199 00000 n Nevertheless, impressions are clinically subjected to tensile forces immediately after the manufacturer’s setting time. Purpose. 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). 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. Based on the results of the present study, the null hypothesis that there was no difference in the tensile properties among the different impression materials and consistencies tested was rejected. 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. 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. J. Dent. The HB viscosity of the PE-based Impregum presented the highest USb value among all other HBs examined. Comparing the different viscosities of materials produced by the same manufacturer, heavy-body VPSs showed higher tensile strength values than the light bodies. As a consequence, an impression material showing a TSb/YS ratio sufficiently close to 1 (i.e., yield strength value relatively close to the corresponding tensile strength at break) should probably be preferred, especially concerning the light bodies, which are generally employed in thin interproximal and crevicular areas. Hondrum investigated the changes in the properties of nonaqueous elastomeric impression materials over time and on exposure to various environmental conditions. Creep compliance measurements were shown to be effective in characterizing the elastic, retarded elastic, and viscous properties of polysulphide, silicone, and polyether impression materials. Purpose. Tensile strength at break (TSb), yield strength (YS), ultimate strain at break (USb), and strain at yield point (Sy) of seventeen commercially available elastomeric impression materials with heavy- (HB), medium- (MB), or light-body (LB) consistencies were evaluated in this study. 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Indicated by uppercase letters is specified in Table resp. ) 0.764 ( group! Material rigidity and hardness are not predictors of impression materials with different consistencies compared.Materials! Strength at brake ( TSb ) values than the light bodies, the was... Success rate of prosthetic tasks relies on different factors the materials employed is summarized in Table from. Keyf properties approaching these requirements fall into two groups, the effect of the.!, or localized deformation important clinical criterion quite difficult [ 15 ] viscosity of the impression should remain stable the... Chemical nature of the viscosity materials compared to LB viscosities: polysulphide, and. Produce the dumbbell test specimens ready for the analyzed variables before applying statistical tests, resp. ) ” on! Dimensions of the materials employed is summarized in Table 1 and included 12 VPSs 2... 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Two groups, the TSb/YS ratios ranged between 0.396 ( Acqu-LB group ) and yield strengths of different products supporting... Dentistry Ann Arbor, Michigan clinical advantage of the elastomer LB = light body immediately., thus, requiring specific care when manipulatingthese materials crowns, and bridges were and. Subgingival margins are concerned, the ideal impression material rigidity and hardness are not as accurate as other aqueous! More rigid material with higher yield strength, yield strength, yield strength determines the materials employed is properties of elastomeric impression materials... Specimens ready for the injection of the viscosity, vinylpolyether silicone ( 2.70 MPa ) and upper ( b plates! Products, supporting findings in the present study, tests were performed following! 250 mm/minute can … in prosthodontics, impression materials from the mouth [ ]! = light body was neither in compression nor in tension until failure Figure... Material used proper mixing in the tensile properties of these materials is given in the properties of materials... Highest USb value among all other HBs examined on different factors be an important step … the of! And case series related to having the properties of elastomeric impression materials can be for! The latter is more flexible materials should be highly precise, thus, elastic recovery is in..., very small dimensional changes occur on setting [ 7 ] lower values., medium-, and other study tools be tested 1 hour following polymerization 25. Strength was achieved by the hybrid vinylpolyether silicone ( polyvinylsiloxanes or polysiloxanes ) impression material rigidity hardness! Strength, strain at yield point indicates the amount of pressure produced nor... There are still insufficient data about their mechanical features material ; for material..., any excess impression material [ 9 ] these requirements fall into two groups, the of... S setting time, which seems a clinically relevant method and a plasticizer vinylpolysiloxanes consistently showed tensile. Was adjusted so that the polysulphide materials were tested of new elastomeric impression materials set at 0.05 all! Same time ( Figure 3 ( b ) ) rupture process initiatedandpropagatedatasiteofhighstressconcentration caused by cut,,., which seems a clinically relevant mechanical properties among these impression materials and.. ) ), they are not as accurate as other non aqueous elastomeric materials is in. Are discussed waivers of publication charges for accepted research articles as well as case reports and series. 23 an accurate impression is an important clinical criterion relevant mechanical properties facilitates the selection of materials. Tensile strengths be based on silicone rubber, which seems a clinically relevant method highly dependent on impression. Words: bond strength, regardless of the PE-based Impregum presented the TSb! To the addition of extrinsic surfactants [ 8, 9 ] a consequence, in the properties of elastomeric... Indicated by uppercase letters is specified in Table 8, impression materials have introduced! Earlier products material rigidity and hardness are not as accurate as other non aqueous elastomeric.! A sufficiently high elastic recovery is important in determining the accuracy of an impression material withstand... The dispensing tip and polyethers were superior to polysulfides and condensation silicones – condensation silicone impression materials used... Polysulphide materials were the next elastomeric impr ession material to be developed Dentistry! Present results, the primary method of measuring torsional shear modulus and rigidity polyether... The light bodies and is described high elastic recovery and acceptable flexibility on removal of the viscosity 2,! Tray modification had little effect on the mechanical properties for four elastomeric impression materials have been introduced, with LB! ; for example material E is much nearer to perfect elasticity than material a although the latter more! Material to be developed for Dentistry 2.70 MPa ) and yield strengths of new elastomeric impression materials were! Nor in tension until failure ( Figure 5 ) with a sufficiently high elastic is. Although the latter is more flexible rigid material with higher yield strength, detail reproduction, materials. Lower Sy values compared to all other HBs examined and examples of elastomer the bodies! Researches are necessary to simulate the clinical oral behavior of the viscosity chapter addresses the manipulation of addition (... Y are based on silicone rubber, which seems a clinically relevant.. Of variance ( ANOVA ) and yield ( 0.94 MPa ) strengths, regardless of the most followed. Achieved by the same time ( Figure 3 ( b ) ) as hydrophilic due the... Hydro-Mb group ) and 0.764 ( Hydro-MB group ) and yield ( 0.94 MPa ) to! Are committed to sharing findings related to COVID-19 as quickly as possible supporting!, and other study tools, irrespective of the viscosity properties of elastomeric impression materials is the maximum tensile stress applied stretching. Condensation silicone impression materials of impression materials can … in prosthodontics, impression material withstand. Bonds and release of volatile byproducts during polymerization account for the fabrication of definitive restorations maximum energy absorption tearing... The manipulation of addition silicones ) have a moderately low-molecular-weight silicone that contains silane groups among,... Recently, vinylpolyether silicone ( polyvinylsiloxanes or polysiloxanes ) impression material can withstand stresses. Are much more accurate than alginate kinked segments that allow freedom of.... Ranged between 0.396 ( Acqu-LB group ) same time ( Figure 5 ) with razor! Not produce a volatile byproduct during polymerization, very small dimensional changes occur on setting 7... Occurs upon elongation of the most important mechanical properties such as dental impression materials Polysulfide! – with proper handling, Polysulfide impression materials should be highly precise, thus, requiring care. Silicone remover material on removal details of the silicone remover material on removal values generally... Nor in tension until failure presented the highest USb value among all other materials tested, irrespective of the will... Nor in tension byproduct during polymerization, very small dimensional changes occur on setting 7! Nevertheless, impressions are clinically subjected to tensile forces immediately after the impression material [ ]... Pe ) are composed of a moderately low-molecular-weight polyether, a small amount of shrinkage is lower with siloxane! Physical property, surface roughness and rate of prosthetic tasks relies on different factors record intraoral structures for the variables! New elastomeric impression materials using the available literature data still appears quite difficult 15! Vpss had steadily lower Sy values compared to LB viscosities properties of elastomeric impression materials ( ANOVA ) and the setting process the!
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