• The Journal of Korean Academy of Prosthodontics
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• v.44 no.4
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• pp.363-373
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• 2006

Statement of Problem : The accuracy and dimensional stability of elastomeric impression materials have been the subject of numerous investigation. Few studies have addressed the effect of changes in time on the dimensional stability of impression materials. Purpose: The purpose of this investigation was to evaluate the effects of elastomeric impression materials and storage time on dimensional stability. Materials and methods: A total of 75 impressions were made of epoxy resin dies mimicked prepared 3-unit fixed partial denture. The dies had 1 buccolingual, 1 mesiodistal and 1 occlusogingival lines and interpreped dot. Impression materials investigated included two polyether impression materials and three polyvinylsiloxane impression material. 15 specimens were made of each impression material and poured by type IV stone over times (30 minutes, 24 hours, 72 hours) after mixing; the same examiner measured each specimen 3 times at a magnification of 3.5$\times$. All statistical tests were performed with the level of significance set at .05. Results : The results indicated that significant difference at any measuring point of stone dies of the polyether impression materials and when measurements at 30 minutes, 24 hours, and 72 hours were compared ; the length of measuring point increased significantly as time passed by. However this result is not significant clinically. Analysis also showed significant differences at any measuring point when polyvinylsiloxane and polyether impression materials were compared and significant differences clinically. Conclusion: Under the conditions of this study, the shrinkage rate of the polyvinylsiloxane and polyether impression materials significantly increased as time passed by. The polyether impression materials showed higher shrinkage significantly, while the shrinkage rate of all five materials showed a significant time-dependent increase.

• Journal of Korean society of Dental Hygiene
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• v.8 no.4
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• pp.89-99
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• 2008

In this study, polyvinylsiloxane impression materials were investigated to examine the characteristics of the impression materials that affect the accuracy of the final restoration. The flow property of impression materials which can reproduce the detail in the oral cavity and accurately duplicate it, and the tear strength and strain-in-compression which can cause problems when it is being removed from the oral cavity were studied. The results are as follows. 1. As for the flow properties of impression materials, Imprint II was 18.24${\pm}$0.30, which was the highest: and Twinz was 8.9${\pm}$0.62, which was the lowest. There was no significant difference among Imprint II, Examixfine, and Genie(p<0.05). 2. As for the tear strength of impression materials, Imprint II had the highest level, while Genie had the lowest value. There was no significant difference between Twinz and Genie(p<0.05). 3. As for the strain-in-compression, there were significant differences by impression material groups(p<0.05); the strain-in-compression of Examixfine was shown to be the highest at 5.56${\pm}$0.56, Twinz and Imprint II followed respectively, and Genie has the lowest at 3.19${\pm}$0.23. 4. Flow showed the correlation with tear strength but no significant connection to strain-in-compression. Also, there was no significant correlation between the tear strength and strain-in-compression (p<0.05). Making impression to reproduce oral tissue and tooth is an important part of making final restoration. The accuracy of impressions is influenced by the methods of taking impression or other condition. However the property itself of impression materials is the most essential and the materials with proper qualities should be selected.

• Journal of Industrial Technology
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• v.36
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• pp.39-43
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• 2016

The purpose of this study is to determine and compare the mechanical and flow properties of polyvinylsiloxane impression pastes. Twelve polyvinylsiloxane impression materials were used. As mechanical properties, tensile strength and tear resistance were measured. Impression materials are subjected to tensile stresses when they are removed from the oral cavity and from stone models and tear resistance is the ability of the material to resist tearing under a tensile stress. Flow is dependent on the ability of the material to resist shear forces. Flow tests were performed to determine the handling characteristics and was measured using a shark fin testing device. An impression material must be able to penetrate the narrow subgingival sulcus and tight interproximal areas. Therefore, it must be able to resist the shear forces as it is pushed between tooth and gingival walls. It is necessary to understand the properties of interocclusal recording materials and is considered that the results obtained in this study will provide guideline information for the manufacturing of impression materials and for selecting appropriate impression materials.

• Journal of dental hygiene science
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• v.6 no.4
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• pp.231-235
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• 2006

This study evaluated the properties of polyvinylsiloxane impression materials: Strain-in-compression, Elastic recovery, Consistency, and Wettability. Four polyvinylsiloxane impression materials(Examixfine, GC, Japan; Aquasilultra, Dentsply, USA; Extrude, Kerr, USA; Perfect-F, Handae, Korea) were used in this study. The measured data were analyzed with SPSSWIN 12.0 program. The results were as follows : 1. The strain-in-compression values showed that Extrude had the lowest value, 4.86% and Examixfine had the highest value, 6.78%. Significant difference between Examixfine and Perfect-F was not found but the other groups had significant differences(p = 0.000). 2. In the elastic recovery test, Extrude had the highest, 99.83% and Perfect-F had the lowest, 96.54%. There is no significant difference between Examixfine and Aquasilultra. The other impression material groups showed significant differences(p = 0.000). 3. The measurement of consistency results that the diameter of Examixfine was the largest, 45.12mm and one of Perfect-F was the smallest, 40.28 mm. No differences were shown between Examixfine and Aquasilultra and between Extrude and Perfect-F(p = 0.001). 4. Aquasilultra had a better hydrophilicity($47.85^{\circ}$) than other materials. Perfect-F had a larger contact angle($94.89^{\circ}$) and was hydrophobic. There were significant differences between groups(p = 0.000). 5. As for correlation among the test types, contact angle correlated with strain-in-compression, elstic recovery and consistency. The strain-in-compression had correlation to contact angle and elastic recovery. The elastic recovery correlated with contact angle and strain-in-compression. And the consistency had correlation to contact angle.

• Elastomers and Composites
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• v.43 no.2
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• pp.88-103
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• 2008

This study was purposed to investigate the effects of surfactants and fillers on physical properties of hydrophilic polyvinylsiloxane dental impression materials (PVS). Incorporation of surfactants enhanced the hydrophilicity of the PVS, however, it induced increased viscosity and permanent deformation ratio, delayed setting, and decreased tensile strength. At high concentrations of surfactant, the tensile strength was observed to decrease significantly due to the internal pore formation. Especially, the hydrophilicity of the PVS was significantly enhanced with the addition of Silwet L-77. However, the viscosity, strain in compression, pore formation, and setting time increased whereas the elastic recovery rate and strength remarkably decreased. The PVS dental materials containing Span 20 showed the lowest degree of viscosity increase, delayed setting, pore formation, and hydrophilicity. The delayed setting, pore formation, and strength decrease caused by the incorporation of surfactant were improved by substituting the crystalline quartz filler with diatomaceous earth while the contact angle of PVS dental materials increased.

• Elastomers and Composites
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• v.44 no.2
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• pp.150-155
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• 2009

This study examined the effects of the concentration variation of the silyl hydride (Si-H) functional group in polymethylhydrogen siloxane cross-linker and the vinyl-functional group in silicone prepolymer on the physical properties of the dental polyvinylsiloxane impression materials (PVS). When the SiH/Vinyl ratio was 1.6 (Group $\underline{C6}$ containing ${\underline{C}}ross$-linker $\underline{6}$ parts), the setting rate was too slow even though their tensile strength was the highest within the tested groups. When the SiH/Vinyl ratio was 3.2 (Group C12), the setting rate was too fast to allow appropriate working time even though their mechanical properties were good. The C14 group showed rather lower tensile strength compared to the groups having lower cross-linker contents. Notably, too much incorporation of cross-linker, like C16 group, induced delay of the setting, by which the mechanical and manipulation properties were detrimentally affected.

• The Journal of Advanced Prosthodontics
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• v.1 no.2
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• pp.63-67
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• 2009

STATEMENT OF PROBLEM. Use of custom tray and tray adhesive is clinically recommended for elastomeric impression material. However there is not clear mention of drying time of tray adhesive in achieving appropriate bonding strength of tray material and impression material. PURPOSE. This study is to investigate an appropriate drying time of tray adhesives by evaluating tensile bonding strength between two types of polyvinylsiloxane impression materials and resin tray, according to various drying time intervals of tray adhesives, and with different manufacturing company combination of impression material and tray adhesive. MATERIAL AND METHODS. Adhesives used in this study were Silfix (Dentsply Caulk, Milford, Del, USA) and VPS Tray Adhesive (3M ESPE, Seefeld, Germany) and impression materials were Aquasil Ultra (monophase regular set, Dentsply Caulk, Milford, Del, USA) and Imprint II Garant (regular body, 3M ESPE, Seefeld, Germany). They were used combinations from the same manufacture and exchanged combinations of the two. The drying time was designed to air dry, 5 minutes, 10 minutes, 15 minutes, 20 minutes, and 25 minutes. Total 240 of test specimens were prepared by auto-polymerizing tray material(Instant Tray Mix, Lang, Wheeling, Il, USA) with 10 specimens in each group. The specimens were placed in the Universal Testing machine (Instron, model 3366, Instron Corp, University avenue, Nowood, MA, USA) to perform the tensile test (cross head speed 5 mm/min). The statistically efficient drying time was evaluated through ANOVA and Scheffe test. All the tests were performed at 95% confidence level. RESULTS. The results revealed that at least 10 minutes is needed for Silfix-Aquasil, and 15 minutes for VPS Tray Adhesive-Imprint II, to attain an appropriate tensile bonding strength. VPS Tray Adhesive-Imprint II had a superior tensile bonding strength when compared to Silfix-Aquasil over 15 minutes. Silfix-Aquasil had a superior bonding strength to VPS Tray Adhesive-Aquasil, and VPS Tray Adhesive-Imprint II had a superior tensile bonding strength to Silfix-Imprint II at all drying periods. CONCLUSION. Significant increase in tensile bonding strength with Silfix-Aquasil and VPS Tray adhesive-Imprint II combination until 10 and 15 minutes respectively. Tray adhesive-impression material combination from the same company presented higher tensile bonding strength at all drying time intervals than when using tray adhesive-impression material of different manufactures.

• Elastomers and Composites
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• v.44 no.1
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• pp.76-83
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• 2009

The purpose of this study was to investigate the effects of combined use of several types of silicone polymers on the physical properties of the dental polyvinylsiloxane impression materials (PVS). Four types of silicone prepolymers having different molecular weight and vinyl group position, and two types of cross-linkers having differently located silyl hydride functional groups were used in various combinations for the formulation. The samples containing bimodal or trimodal prepolymers showed higher tensile strength, elongation at break, and elastic deformation than those containing only one type of prepolymer. The samples using CR210 cross-linker which has side- and terminal-silyl hydride groups showed higher elastic deformation and elongation at break than those using CR101 cross-liker which has side-only silyl hydride group. High vinyl content prepolymer having side vinyl group delayed setting even though it enhanced tensile strength. Further studies are needed to clarify the specific role of this component on setting time and to find appropriate controlling methods for making improved PVS with optimum workability.

• The Journal of the Korean dental association
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• v.38 no.8 s.375
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• pp.757-764
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• 2000

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.3
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• pp.199-207
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• 2013

Purpose: The importance of occlusal contacts of the natural dentition for durability of teeth, mandibular stabilization, and restorative dentistry is well known. The purpose of this study is to analyze the occlusal contact and guidance pattern of Koreans by evaluating the static occlusion on maximal intercuspal position and measuring dynamic occlusion during straight protrusion. Materials and methods: The occlusal contacts at maximal interincisal position and the occlusal guidance pattern during straight protrusion of 29 subjects were recorded with shimstock foil (Whaledent, Langenau, Germany), T-Scan III (Tekscan Inc., Boston, MA, USA), polyvinylsiloxane registration material (Genie Bite, Sultan Healthcare, Hackensack, NJ, USA) and compared. Occlusal registration procedures were repeated 3 times. The position was fixed to an upright position and the head position was fixed with the Frankfurt horizontal plane paralleling the horizontal plane. Fisher's Exact Test (R-General Public License, ver. 2.14.1) and Pearson's Test were used to assess the significance level of the differences between the experimental groups (${\alpha}=.05$). Results: When using shimstock foil, T-Scan III system, and polyvinylsiloxane registration material, most of the patients showed contact on anterior, premolar, and molar teeth during maximal intercuspal position. Approximately 51% of maximal intercuspal position showed anterior contact using shimstock foil. When examining the protrusive movement using shimstock foil and T-Scan III system, guidance pattern with the central incisor was the most common. Conclusion: During maximal intercuspal position, there were cases in which not all of the teeth showed occlusal contact. During mandibular protrusive movements, one or more maxillary central incisors frequently joined in straight protrusion and the posterior teeth were disoccluded. Therefore, the anterior teeth protect the posterior teeth, and vice versa. Thus, mutually protected occlusion should be applied when reconstructing occlusion.