Rheological properties of polyvinylsiloxane impression materials before mixing and during setting related to handling characteristics

Lee, Hyang-Ok,Lee, In-Bog 한국유변학회 2012 Korea-Australia rheology journal Vol.24 No.3

The purpose of this study is to determine and compare the handling and rheological properties of polyvinylsiloxane impression pastes before mixing and during setting, and to investigate the effect of its constituents on the properties of the materials. Five polyvinylsiloxane impression materials (Examixfine, Extrude, Honigum, Imprint II, and Express) were used. A flow test and a drip test were performed to determine the handling characteristics. The rheological properties of each impression material prior to mixing (shear stress, viscosity) and during setting (storage modulus G', loss modulus G", loss tangent $tan{\delta}$) were measured with a stress-controlled rheometer at $25^{\circ}C$ and $32^{\circ}C$, respectively. Inorganic filler content of each impression material was measured and observed with a SEM. The molecular weight distribution of polymer matrix was determined with a gel permeation chromatography (GPC). Express and Honigum display lower flow compared to the other materials, due to their high yield-stress values. Examixfine exhibits the greatest flow. All materials display pseudoplastic behavior, excluding the Examixfine catalyst. The viscosities at low shear rate are greatest for Express and Honigum; however, under high shear conditions, the viscosities of Extrude and Honigum are the lowest. Following mixing, each material show an increase in G', finally reaching a plateau, and the $tan{\delta}$ rapidly decreases with time. Imprint II shows the highest final G' as well as the most rapid decrease in $tan{\delta}$. Express and Imprint II present the highest filler content and rough filler surface, while Honigum shows the lowest filler content and small filler particles. Most products are composed of polymers over 30 kDa and oligomers less than 1 kDa. Each impression material possesses different rheological properties, which significantly affect the handling characteristics. The yield stress of the impression material minimizes unnecessary flow prior to and after seating. Viscoelastic change during setting of each impression material determines the setting time and the stiffness after setting. These rheological properties of impression materials are affected by the filler content and molecular weight distribution of polymer matrix.

인상채득 후 시간경과에 따른 고무인상재의 체적변화

이홍석,조석규,윤태호,박주미,송광엽,Lee Hong-Seok,Cho Suck-Kyu,Yoon Tae-Ho,Park Ju-Mi,Song Kwang-Yeob 대한치과보철학회 2006 대한치과보철학회지 Vol.44 No.4

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.

Drying time of tray adhesive for adequate tensile bond strength between polyvinylsiloxane impression and tray resin material

Yi, Myong-Hee,Shim, Joon-Sung,Lee, Keun-Woo,Chung, Moon-Kyu 대한치과보철학회 2009 The Journal of Advanced Prosthodontics Vol.1 No.2

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 Gai-ant (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, Ⅱ, 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-lmprint Ⅱ, to attain an appropriate tensile bonding strength. VPS Tray Adhesive-lmprint 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-lmprint Ⅱ had a superior tensile bonding strength to Silfix-lmprint 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.

Rheological properties of polyvinylsiloxane impression materials before mixingand during setting related to handling characteristics

Hyang-Ok Lee,이인복 한국유변학회 2012 Korea-Australia rheology journal Vol.24 No.3

The purpose of this study is to determine and compare the handling and rheological properties of poly\-vinylsiloxane impression pastes before mixing and during setting, and to investigate the effect of its con\-stituents on the properties of the materials. Five polyvinylsiloxane impression materials (Examixfine, Extrude, Honigum, Imprint II, and Express) were used. A flow test and a drip test were performed to deter\-mine the handling characteristics. The rheological properties of each impression material prior to mixing (shear stress, viscosity) and during setting (storage modulus G', loss modulus G'', loss tangent tand) were measured with a stress-controlled rheometer at 25oC and 32oC, respectively. Inorganic filler content of each impression material was measured and observed with a SEM. The molecular weight distribution of polymer matrix was determined with a gel permeation chromatography (GPC). Express and Honigum display lower flow compared to the other materials, due to their high yield-stress values. Examixfine exhibits the greatest flow. All materials display pseudoplastic behavior, excluding the Examixfine catalyst. The viscosities at low shear rate are greatest for Express and Honigum; however, under high shear conditions, the viscosities of Extrude and Honigum are the lowest. Following mixing, each material show an increase in G', finally reach\-ing a plateau, and the tand rapidly decreases with time. Imprint II shows the highest final G' as well as the most rapid decrease in tand. Express and Imprint II present the highest filler content and rough filler surface, while Honigum shows the lowest filler content and small filler particles. Most products are composed of polymers over 30kDa and oligomers less than 1kDa. Each impression material possesses different rheo\-logical properties, which significantly affect the handling characteristics. The yield stress of the impression material minimizes unnecessary flow prior to and after seating. Viscoelastic change during setting of each impression material determines the setting time and the stiffness after setting. These rheological properties of impression materials are affected by the filler content and molecular weight distribution of polymer matrix.

친수성 Polyvinylsiloxane 인상재의 putty와 light body의 결합강도

강재경,김경남,조리라,정경호 대한치과기재학회 2000 대한치과재료학회지 Vol.27 No.4

Polyvinylsiloxane is the most accurate and dimensionally stable material among the dental impression materials which replicate the teeth and oral tissues. There are two methods for taking impressions with the polyvinylsiloxane: one step simultaneous polymerization; and putty/wash two step reline technique. The purpose of this study was to evaluate tensile bond strength between putty and wash material under the conditions of contamination with saliva or water at taking impression by putty/wash technique. The materials used in this study were 4 hydrophilic polvinylysiloxane impression materials of putty and light body type(Perfect-F, Handae Chemical, Korea; Contrast, VOCO, Germany; Exaflex and Examix, GC, Japan; Express and Imprint Ⅱ, 3M, U.S.A.). First, putty material filled in one perforated metal mold with diameter of 15 ㎜ and height of 19 ㎜ was set, and it was bonded with light body material filled in other paired metal mold before setting. Tensile bond strength was measured at a cross-head speed of 300 ㎜/min by universal testing machine (Instron 6022, Instron Co., U.K.) after 10 minutes from the joining two mold in order to set completely. As results, tensile bond strength of Contrast, Examix and Perfect-F showed no significant difference with control group on contamination with saliva or water, and it showed cohesive failure in the light body. However, Imprint Ⅱ showed the highest strength among these tested materials and showed adhesive failure at 5 specimens in the case of contamination with saliva and 4 specimens with water. From the results of this study, each product use possible cross bond and the tensile bond strength of some materials showed lower value on contamination with saliva.

Change of surface property of dental impression materials according to time and disinfection

Kim, Soo-Hwa,Lee, Doug-Youn,Kim, Kwang-Mahn,Kim, Kyoung-Nam John Wiley Sons, Ltd. 2008 Surface and interface analysis Vol.40 No.3

<P>The purpose of this study was to investigate the hydrophilicity of dental impression materials. Two ultrahydrophilic (Fusion, Genie) and four hydrophilic (Imprint II, Aquasilultra, Twinz, Perfect-F) impression materials were used. Initially, 0.5% NaOCl and 1% povidone were used as disinfectants. In order to investigate the change of the surface wettability of impression materials according to the elapsed time after mixing, the contact angles were measured at 30 s and 2 min after mixing, respectively. Contact angles were also measured before and after disinfection. The contact angles of the ultrahydrophilic impression materials were lower at 2 min than at 30 s, whereas those of the hydrophilic impression materials showed the opposite result (p < 0.05). Fusion and Perfect-F had higher contact angles in the NaOCl-group and lower contact angles in the povidone-group than those of nondisinfection group (p < 0.05). The contact angles of Aquasilultra and Twinz in the povidone-group were higher than those in the nondisinfection group (p < 0.05). The elapsed time after mixing and disinfection of impression materials affected the contact angle of water on the surface of the impression materials. These results suggested that impression materials should only be used within the scope that their wettability is not degraded. Copyright © 2008 John Wiley & Sons, Ltd.</P>

실리콘 폴리머의 비닐그룹에 대한 가교제의 Si-H 비율이 폴리비닐실록산 치과용 인상재의 물성에 미치는 영향

주동현 ( Dong Hyun Ju ),정영화 ( Young Hwa Jeong ),송호준 ( Ho Jun Song ),최창남 ( Chang Nam Choi ),박영준 ( Yeong Joon Park ) 한국고무학회 2009 엘라스토머 및 콤포지트 Vol.44 No.2

본 연구는 폴리비닐실록산 치과용 고무인상재의 조성에서 실리콘 프리폴리머 내 비닐그룹에 대한 가교제 내 Si-H 그룹의 함량비 차이가 물성에 미치는 영향을 평가하였다. SiH/Vinyl 비가 1.6으로 가교제 함량이 낮은 C6군(Cross-linker 6 parts 함유)은 인장강도가 실험군 중 가장 높았으나 경화속도가 너무 느렸고, SiH/Vinyl 비가 3.2인 C12군은 기계적 성질은 좋았으나 경화가 너무 빠르게 진행되어 조작이 용이하지 않은 단점을 보였다. 그러나 C14군은 가교제 함량이 더 낮은 실험군들에 비해 낮은 인장강도를 보였으며, C16군은 경화반응이 오히려 더 지연됨을 보여 과다한 가교제 첨가는 기계적 성질과 조작성에 불리한 영향을 미침을 알 수 있었다. 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 C6 containing Cross-linker 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.

폴리비닐실록산 치과용 고무인상재의 친수성 향상을 위한 계면활성제의 응용과 물성에 미치는 영향

박영준 ( Yeong Joon Park ),황문진 ( Moon Jin Hwang ),김민강 ( Min Kang Kim ),송호준 ( Ho Jun Song ),하광 ( Kwang Ha ),강신영 ( Shin Young Kang ) 한국고무학회 2008 엘라스토머 및 콤포지트 Vol.43 No.2

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.

실리콘폴리머의 혼합사용이 폴리비닐실록산 치과용 인상재의 물성에 미치는 영향

임창하 ( Chang Ha Lim ),김민강 ( Min Kang Kim ),김영철 ( Young Chul Kim ),박남국 ( Nam Cook Park ),송호준 ( Ho Jun Song ),박영준 ( Yeong Joon Park ) 한국고무학회 2009 엘라스토머 및 콤포지트 Vol.44 No.1

본 연구는 비닐작용기의 위치가 다른 실리콘 프리폴리머와 수소작용기의 위치가 다른 가교제, 그리고 이들의 혼합사용이 제조된 치과용 폴리비닐실록산 고무인상재의 물성에 미치는 영향을 연구하였다. 한 종류의 중점도 프리폴리머를 사용한 실험군은 인장강도, 파단신율, 압축시 변형률이 다른 특성의 프리폴리머들을 혼합사용한 경우보다 낮은 값을 보였다. 측부와 말단에 수소작용기가 있는 CR210 가교제를 사용한 실험군은 측부에만 수소작용기가 있는 CR101 가교제를 사용한 실험군에 비해 압축시 변형률과 파단신율이 더 높았다. 측쇄에도 비닐기를 갖는 높은 비닐함량의 프리폴리머를 사용한 경우는 더 높은 인장강도를 보였지만, 경화 속도가 늦어서 임상 사용에 적합한 작업성을 갖는 치과용 인상재를 만들기 위해서는 이 성분이 경화시간에 미치는 영향과 이를 조절할 수 있는 방안에 대한 지속적인 연구가 필요하다고 생각한다. 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.