Vinyl Siloxanether Research Articles

The Accuracy of Casts Obtained Using Different Impression Techniques and Impression Materials in Combined Parallel and Angulated Implants: An In Vitro Study.

Aim The aim of this in vitro study was to evaluate and compare the accuracy of casts made from two elastomeric impression materials (polyvinyl siloxane (PVS) and vinylsiloxanether (VSE)) using different impression techniques on parallel and angulated implants. Materials and methods The reference model was fabricated using auto-polymerizing acrylic resin on which three implant analogs were placed of which two were parallel to each other and the third at 20-degree mesial angulation. A total of 60 impressions were madeof which 30 were by using PVS and 30 by VSE. For each material, 10 impressions were made by closed tray technique, 10 by open tray techniqueand 10 by open tray with sandblasting and adhesive coating of the impression copings technique. The inter-analog distances of the casts obtained were evaluated and compared with the reference model by a vision measuring machine. Data were analyzed using analysis of variance (ANOVA), Tukey's Honest Significant Difference (HSD) post hocand independent samples t-test. Results When the inter-analog distances of the duplicate casts were compared with the reference model, the mean error rates for parallel implants decreased in the order of closed tray technique, open tray technique and open tray with sandblasting and adhesive coating of the impression copings technique for both PVS and VSE impression materials. Similarly, the same order was observed for angulated implants for both impression materials. Using the closed tray technique, there was no statistically significant difference in the accuracy of the cast between the two materials for parallel implants (P = 0.525) and also no significant difference between the two materials for angulated implants (P = 0.307). Similarly, there was no statistically significant difference in the accuracy of the cast between the two materials for parallel implants (P = 0.455) and also no significant difference between the two materials for angulated implants (P = 0.519) using the open tray technique. Whereas for the open tray with sandblasting and adhesive coating of the impression copings technique, VSE produced a more accurate cast than PVS for parallel implants and was statistically significant (P = 0.033); however, there was no significant difference between the two materials for angulated implants (P = 0.375). Conclusion For parallel implants, VSE by an open tray with sandblasting and adhesive coating of the impression copings technique produced a more accurate cast than PVS. For angulated implants, there was no significant difference between the two materials and it was only the technique that significantly affected the accuracy of the cast.

Dimensional Stability of Elastomeric Impression Material After Disinfection Via Immersion and Microwave Irradiation

Aims: This study aimed to evaluate and compare the dimensional stability of two elastomeric impression materials, namely polyvinyl siloxane (PVS) and vinyl siloxanether (VSE), subjected to chemical immersion and microwave irradiation for disinfection. Materials and Methods: Sixty discs of PVS and VSE impression materials each were prepared using a stainless-steel test die and ring in accordance with ANSI/ADA Specification No. 19. Twenty discs of each impression material were disinfected by chemical immersion for 10 min; another 20 discs were subjected to dry microwave irradiation for 3 min. The other 20 discs served as a control group. Dimensional stability measurements were then performed using an image analyzer at 20× magnification. The data were analyzed by one-way analysis of variance (α=0.05) and Bonferroni (post hoc) test for multiple comparisons to detect significant differences between the groups. Results: When subjected to microwave irradiation, both PVS and VSE showed dimensional changes, but the changes were within the limit of 1.5% set by ANSI/ADA (P<0.00). VSE showed markedly better results than PVS for both disinfection methods. The immersion disinfection method resulted in a higher average percentage of linear dimensional changes than both the microwave irradiation and the control for VSE and PVS impression materials. Conclusion: VSE exhibited excellent dimensional stability than PVS under both chemical immersion and microwave irradiation. Microwave irradiation using conventional microwave ovens can be used in clinical settings as an alternative to other disinfection techniques because the dimensional changes of the elastomeric impression materials subjected to microwave irradiation have been observed to be within the clinically acceptable limit set by the ANSI/ADA standard.

Penetration and Tensile Strength of Various Impression Materials of Vinylsiloxanether, Polyether, and Polyvinylsiloxane Impression Materials.

Objectives The aim of this study was to evaluate and compare penetration ability and tensile strength among vinylsiloxanether (VSE), polyether (PE), and polyvinylsiloxane (PVS) elastomeric dental impression materials. Materials and Methods The models were constructed for penetration ability test by simulated gingival sulcus width and moist environment. The 0.05, 0.1, and 0.2 mm of simulated gingival sulcus widths were used. Each simulated gingival sulcus width was impressed 10 repeats per one elastomeric impression material. All extension of elastomeric dental impression materials was scaled by Measuring Microscope (MM-11; Nikon, Tokyo, Japan). On the issue of the tensile strength study, the models were constructed following type 1 of the ISO 37:2017 specifications and/or type C of ASTM.D412 specifications. The two-way analysis of variance (ANOVA) and Tukey's honest significant difference test were performed in the penetration ability test. The one-way ANOVA and Dunnett's T3 test were performed in the tensile strength test. The significance level was set at 0.05. Results PE showed the best extension into all widths of simulated sulcus followed by VSE and PVS, respectively. PVS was significantly higher in tensile strength than VSE and PE, while VSE was significantly higher than PE. Conclusion Penetration ability of elastomeric dental impression materials was depended on gingival sulcus width. The wider the sulcular width, the better the penetration ability of elastomeric dental impression materials. PE presented the best penetration ability, while the novel PVS showed highest tensile strength.

Peel bond strength between 3D printing tray materials and elastomeric impression/adhesive systems: A laboratory study

ObjectivesThe present study aimed to evaluate the bonding between three 3D printed custom tray materials and three elastomeric impression/adhesive systems using the peel test. MethodsTest blocks were 3D printed by three different technologies using Dental LT, FREEPRINT tray, and polylactide (PLA) tray materials. The reference test blocks were conventionally fabricated with Zeta Tray LC, a light-curing resin. The surface topographies of the four tray materials were investigated by scanning electron microscopy (SEM) analyses and roughness measurements. The peel bond strength between the four tray materials and three impression/adhesive systems, vinylsiloxanether (VSXE), vinyl polysiloxane (VPS), and polyether (PE), was measured (n=12 per group). The peeling failure modes and rupture sites were identified microscopically. ResultsThe four tray materials featured different surface topographies. The peel bond strength was not significantly different with VSXE and PE, but PLA and the reference showed higher peel bond strength with VPS than the Dental LT and FREEPRINT tray (p<0.05). The rupture site of adhesive failure in all groups was partly at the adhesive-impression material interface and partly within the adhesive but never at the adhesive-tray material interface. SignificanceThe 3D printed tray materials can achieve satisfactory chemical compatibility with the adhesives of VSXE, VPS, and PE. Surface topographies generated by the 3D printing technologies may affect bonding. Generally, 3D printed tray materials can provide clinically adequate bond strength with the elastomeric impression/adhesive systems. PLA is recommended for bonding with VPS when severe impression removal resistance is detected.

Accuracy of digitization obtained from scannable and nonscannable elastomeric impression materials

Statement of problemElastomeric impression materials have been marketed for optimizing direct digital acquisition without requiring a stone cast. The trueness and precision of the digitization of these new elastomeric impression materials are unclear. PurposeThe purpose of this in vitro study was to compare the trueness and precision of digital dental casts obtained from the direct digitization of 2 types of vinylsiloxanether (VSXE) impression materials by using a laboratory laser scanner. Material and methodsThirty-eight elastomeric impressions were made of a master die with a similar morphology to a premolar crown preparation. The impression materials were Identium (IDE) and Identium Scan (SCAN), designed for direct digitalization. Each impression was digitalized by using an optical scanner to create digital casts. A computer-aided design (CAD) reference model of trueness (CRM) was created and aligned to each digital cast for digital 3-dimensional discrepancy analysis. ResultsThe mean ±standard deviation global trueness of IDE was 53 ±16 μm and that of SCAN was 46 ±3 μm. SCAN digital casts showed higher precision (58 ±5 μm) than IDE (69 ±18 μm) (P<.05). At the margin of the preparation and at the axial surfaces, SCAN models showed higher trueness (3 ±6 μm and 1 ±5 μm) than IDE (15 ±10 μm and 2 ±37 μm), respectively. ConclusionsScannable impressions could be digitalized with higher global precision than conventional elastomeric materials. Higher trueness could be achieved in specific impression locations such as gingival areas or axial walls of preparations, where the light emitted by the scanner was not blocked.

Comparative Evaluation of Dimensional Accuracy and Tear Strength of Vinyl Siloxanether and Polyether Impression Materials: An In Vitro Study

Comparative Evaluation of Dimensional Accuracy and Tear Strength of Vinyl Siloxanether and Polyether Impression Materials: An In Vitro Study

An Objective and Subjective Evaluation of Dental Implant Impressions using Vinylsiloxanether and Polyether Impression Materials−An in Vivo Study

Purpose: This invivo study was planned to subjectively and objectively evaluate dental implant impressions using Vinyl Siloxanether& Polyether impression materials. Method: Two master impression were made for each of the 20 subject, with Vinyl Siloxanether ‘ID’ and Polyether ‘IM’ using the closed tray impression technique after adequate healing. These were subjectively and objectively evaluated using preset standardised criteria. The results were statistically analyzed for noninferiority of ‘IM’ and ‘ID’ by using the Chi – Sqaure test and Fisher’s exact test for the subjective evaluation and for objective evaluation Analysis of Variance (one way ANOVA) was used. Results: On the basis of the subjective assessment of the two impressions ID showed superior ratings in terms of taste (p=0.19) as evaluated by the patient, tear resistance upon removal from mouth (p=0.018) and tear resistance upon removal from stone cast (p=0.046) as evaluated by the operator. However , in terms of clinical handling, hydrophilic properties (p=0.376) and total setting time( 0.147) there was no statistical difference between ID and IM impression materials. On the basis of objective evaluation of the two impression materials, vinyl siloxaneether appears to be a good alternative to polyether in terms of transfer accuracy from oral to model situation with respect to dental implants as there was no statistical difference between the two groups. Conclusion: Vinylsiloxanether which is a chemical combination of polyether and vinylpolysiloxane has superior mechanical and hydrophilic properties while achieving its final hardness, thereby providing accurate implant impressions for the fabrication of successful implant prosthetic restorations

Effect of Impression Materials and Techniques on Impressions Accuracy for Angulated Implants

Purpose: Reproducing the intraoral relationship of implants through impression procedures is the first step in achieving an accurate, passively fitting prosthesis. This study was designed to evaluate the effect of three different impression materials, polyether (PE, ImpregumTMSoft ), additional silicone (PVS, Enthus) and vinyl siloxanether (VSXE, EXA’lence), on the accuracy of impressions in nonparallel implants. Material and Methods: An epoxy resin completely edentulous mandibular model with three implants (OsseoLink USA LLC. 4 mm ×9 mm, internal connection type) with different angles (0 and 15 degrees) was used as reference model. Sixty stone casts were made from the reference model using three impression materials; polyether (PE, ImpregumTMSoft) Group 1, additional silicone (PVS, Enthus) Group 2 and vinyl siloxanether (VSXE, EXA’lence) Group 3 with two impression techniques indirect and direct technique. The inter-implant distances were measured for casts using a coordinate measuring machine and the deviations compared to the reference models were calculated. Data were collected, tabulated and statistically analyzed using one-way ANOVA followed by Tukey’s Post-hoc test to detect significance between groups (P=0.05). Results: Tukey’s Post-hoc test in the indirect technique showed non-significant differences (p>0.05) between VSXE and PVS for ∆ r1 and ∆ r2 while showed significant differences (p> 0.05) between VSXE and PE also between PVS and PE for ∆ r1 and ∆ r2, while Tukey’s Post-hoc test in the direct technique showed significant differences (p<0.05) between VSXE and PVS, between VSXE and PE and between PVS and PE groups for ∆ r1 and ∆ r2.Conclusion: Within the limitations of this study, for nonparallel implant conditions, the distortion values of casts produced by VSXE was significantly lower than casts produced by PVS, which was significantly lower than casts produced by PE in direct impression technique, while VSXE and PVS produced casts with more accuracy compared to casts produced by PE group in the indirect impression technique.

Volumetric evaluation and three-dimensional accuracy of different elastomeric impression materials

Although there is more information on the theoretical shrinkage of different elastomeric impression materials, there are insufficient number of 3-dimensional evaluations on volumetric differences and accuracy of definitive casts. The purpose of this in vitro study was to evaluate volumetric changes and the accuracy of four different impression materials using a 3-dimensional computer-aided measurement method. All definitive casts are compared with the master model by using computer-aided measurements. The 3-dimensional accuracy determined by best-fit alignment method and volumetric changes were identified by volumetric measurements. Detected changes are represented in color-coded maps and cross sections. Condensation silicon was significantly differing from polyether, polyvinyl siloxane and vinyl siloxanether. Except polyvinyl siloxane, vinyl siloxanether presented significantly lowest volumetric difference value from condensation silicon and polyether.

A Comparison of implant impression precision: Different materials and techniques.

BackgroundPrecision of implant impressions is a prerequisite for long-term success of implant supported prostheses. Impression materials and impression techniques are two important factors that impression precision relies on.Material and MethodsA model of edentulous maxilla containing four implants inserted by All-on-4 guide was constructed. Seventy two impressions using polyether (PE), polyvinyl siloxane (PVS), and vinyl siloxanether (VSE) materials with direct and indirect techniques were made (n=12). Coordinates of implants in casts were measured using coordinate measuring machine (CMM). Data were analyzed with ANOVA; t-test and Tukey test were used for post hoc.ResultsWith two-way ANOVA, mean values of linear displacements of implants were significantly different among materials and techniques. One-way ANOVA and Tukey showed significant difference between PE and VSE (P=0.019), PE and PVS (P=0.002) in direct technique, and between PVS and PE (P<0.001), PVS and VSE (P<0.001) in indirect technique. One-way ANOVA and t-test showed significant difference between the two techniques in PVS groups (P<0.001) and in PE groups (P=0.02). Two-way ANOVA showed mean values of rotational displacement of implants were significantly different among materials. One-way ANOVA and Tukey test showed significant difference between PVS and PE (P=0.001) and between PVS and VSE (P=0.012) in indirect groups.ConclusionsOn the basis of the results, when deciding on the material to make an impression of implants, PE is recommended for direct technique while PE and VSE are recommended for indirect technique. Recommended technique for VSE is either direct or indirect; and for PE and PVS is direct. Key words:Polyvinyl siloxane, polyether, vinyl siloxanether, direct technique, indirect technique, All-on-4, coordinate measuring machine.

ACCURACY OF TWO DIFFERENT IMPRESSION MATERIALS IN PARALLEL AND NON PARALLEL IMPLANT POSITIONS

Purpose: Accurate implant impressions play a significant role and serve as a starting point in the process of producing good working casts. This study was designed to evaluate the effect of two different impression materials, additional silicone (Enthus) and vinyl siloxanether (EXA’lence), on the accuracy of impressions in parallel and nonparallel implants.Material and Methods: In this study, two completely edentulous mandibular models were used. Three implants (OsseoLink USA LLC. 4 mm ×9 mm, internal connection type) were placed in each reference model with different angles (0 and 15 degrees). Thirty stone casts were made from each reference model using additional silicone (Enthus polyvinyl siloxane, PVS) and vinyl siloxanether (EXA’lence, VSXE) (n=15 per group) with direct technique. The inter-implant distances were measured for casts using a coordinate measuring machine and the deviations compared to the reference models were calculated. Data were collected, tabulated and statistically analyzed using Student T-test.Results: In parallel condition, the two materials showed non-significant difference in deformation of (∆ r1 or ∆ r2), while in the presence of angulated implants, vinyl siloxanether (EXA’lence, VSXE) impression material showed more accurate results compared to additional silicone (Enthus polyvinyl siloxane, PVS) impression material.Conclusion: Within the limitations of this study, in parallel conditions, the type of impression material cannot affect the accuracy of the implant impressions; however, in nonparallel conditions, vinyl siloxanether (EXA’lence, VSXE) impression material produced more accurate casts than additional silicone (Enthus polyvinyl siloxane, PVS) impression material.

Effect of different impression materials on the marginal fit of frameworks: An in-vitro study

Objectives: The objective of this study was to compare the accuracy of three different impression materials with evaluating the marginal fits of metal frameworks using replica technique. Materials and Methods: A phantom premolar tooth was prepared with a 1 mm circumferential chamfer preparation. Four impression materials: two vinyl polysiloxane (VPS) (Affinis Precious, (Group A); Elite HD, (Group E)), one polyether (Impregum Penta Soft, (Group P)) and one vinyl siloxanether (Identium, (Group I)) were used for producing stone casts of this master model. Twelve measurements per replica were carried out using a light microscope X40 magnification by Leica software, to assess the vertical marginal gap (VMG). Data were analyzed using the analysis of variance followed by Tukey’s test ( p =0.05). Results: Specimens of the Group A and I showed significantly lower VMG values than those of Group E and Group P ( p 0.05). Conclusions: All impression materials were clinically acceptable. As well as composition of the impression materials, size of filler particles and fluid mechanics of flow into very small spaces can be effective on accuracy of the materials.

Accuracy of impression scanning compared with stone casts of implant impressions

Statement of problemAccurate virtual implant models are a necessity for the fabrication of precisely fitting superstructures. PurposeThe purpose of this in vitro study was to evaluate different methods with which to build an accurate virtual model of a 3-dimensional implant in the oral cavity; this model would then be used for iterative computer-aided design and computer-aided manufacturing (CAD-CAM) procedures. Material and methodsA titanium master model with 3 rigidly connected implants was manufactured and digitized with a noncontact industrial scanner to obtain a virtual master model. Impressions of the master model with the implant position locators (IPL) were made using vinyl siloxanether material. The impressions were scanned (Impression scanning technique group). For the transfer technique and pick-up technique groups (each group n=20), implant analogs were inserted into the impression copings, impressions were made using polyether, and casts were poured in Type 4 gypsum. The IPLs were screwed into the analogs and scanned. To compare the virtual master model with each virtual test model, a CAD interactive software, ATOS professional, was applied. The Kruskal-Wallis test was subsequently used to determine the overall difference between groups, with the Mann-Whitney U test used for pairwise comparisons. Through Bonferroni correction, the α-level was set to .017. ResultsThe outcome revealed a significant difference among the 3 groups (P<.01) in terms of accuracy. With regard to total deviation, for all axes, the transfer technique generated the greatest divergence, 0.078 mm (±0.022), compared with the master model. Deviation with the pick-up technique was 0.041 mm (±0.009), with impression scanning generating the most accurate models with a deviation of 0.022 mm (±0.007). ConclusionsThe impression scanning method improved the precision of CAD-CAM-fabricated superstructures.

Comparison of accuracy and reproducibility of casts made by digital and conventional methods

Statement of problemLittle peer-reviewed information is available regarding the accuracy and reproducibility of digitally fabricated casts compared to conventional nondigital methods. PurposeThe purpose of this in vitro study was to compare the accuracy and reproducibility of a digital impression and cast fabrication with a conventional impression and cast fabrication. Material and methodsConventional impressions were made via a 1-step single viscosity technique with vinyl siloxanether material of a typodont master model, and conventional casts were cast from dental stone. Digital impressions were obtained with a digital scanner, and digital stereolithographic models were printed. The typodont and fabricated casts were digitized with a structured light scanner and saved in surface tessellation language (STL) format. All STL records were superimposed via a best-fit method. The digital impression and cast fabrication method was compared with the conventional impression and cast fabrication method for discrepancy, accuracy, and reproducibility. The Levene test was used to determine equality of variances, and a 1-way ANOVA was conducted to assess the overall statistical significance of differences among the groups (n=5, α=.05). ResultsNo significant statistical difference was found between the digital cast and conventional casts in the internal area or finish line area (P>.05). In addition, there was no statistically significant difference between these 2 techniques for a fixed dental prosthesis or single crown (P>.05). However, statistically significant differences were observed for overall areas of the casts in terms of accuracy (P<.01) and reproducibility (P<.001). Digital impression and cast fabrication were less accurate and reproducible than conventional impression and cast fabrication methods. ConclusionsNo statistically significant difference was found between the digital cast and conventional cast groups in the internal and finish line areas. However, in terms of the reproducibility and accuracy of the entire cast area, the conventional cast was significantly better than the digital cast.

Accuracy of different impression materials in parallel and nonparallel implants.

Background:A precise impression is mandatory to obtain passive fit in implant-supported prostheses. The aim of this study was to compare the accuracy of three impression materials in both parallel and nonparallel implant positions.Materials and Methods:In this experimental study, two partial dentate maxillary acrylic models with four implant analogues in canines and lateral incisors areas were used. One model was simulating the parallel condition and the other nonparallel one, in which implants were tilted 30° bucally and 20° in either mesial or distal directions. Thirty stone casts were made from each model using polyether (Impregum), additional silicone (Monopren) and vinyl siloxanether (Identium), with open tray technique. The distortion values in three-dimensions (X, Y and Z-axis) were measured by coordinate measuring machine. Two-way analysis of variance (ANOVA), one-way ANOVA and Tukey tests were used for data analysis (α = 0.05).Results:Under parallel condition, all the materials showed comparable, accurate casts (P = 0.74). In the presence of angulated implants, while Monopren showed more accurate results compared to Impregum (P = 0.01), Identium yielded almost similar results to those produced by Impregum (P = 0.27) and Monopren (P = 0.26).Conclusion:Within the limitations of this study, in parallel conditions, the type of impression material cannot affect the accuracy of the implant impressions; however, in nonparallel conditions, polyvinyl siloxane is shown to be a better choice, followed by vinyl siloxanether and polyether respectively.

Comparative study of Dimensional stability and accuracy of various elastomaric materials

Introduction: Transfer of an accurate replication of the patient’s hard and soft tissue to the dental laboratory is important. An accurate impression will result in a precise fitting cast restoration. Recently a new impression material Vinyl Siloxanether by the manufacturer has been made commercially available. The objective of this in vitro study is to compare the newer material with older ones in terms of accuracy. Methodology A stainless steel model containing two tapered abutments with cross grooves on occlusal and proximal surface for reference measurement was fabricated on a lathe. Total eighty samples were made. Sixteen impressions were made with polyether (medium body), poly Vinylsiloxane (medium body, heavy & light body) and vinyl siloxanether (medium body, heavy & light body) each. The recommended tray adhesive was used for all impression materials and was poured using Type IV gypsum. A Travelling microscope was used to assess dimensions (diameter, height and inter abutment distance) on stone cast poured from the impression of stainless steel model. One-way ANOVA test, Tukey HSD test were used for statistical analysis. Results All casts yielded from five study groups were bigger in the dimensions. The newly formulated vinyl siloxanether impression material yielded more accurate casts than those of addition silicone and polyether impression materials. Conclusion The newly formulated vinyl siloxanether impression material yielded more accurate impressions. The vinyl siloxanether impression material yielded more accurate casts than those of addition silicone and polyether impression materials

Accuracy of the newly formulated vinyl siloxanether elastomeric impression material

A newly formulated vinyl siloxanether elastomeric impression material is available, but there is little knowledge of its accuracy in relation to existing materials. The purpose of this in vitro study was to assess the accuracy of disinfected vinyl siloxanether impressions and compare the accuracy to a common vinyl polysiloxane and a polyether impression system. Impressions were made from a modified dentoform master model containing a simulated crown preparation. Dimensional changes (mm) between the master model and working casts (type IV gypsum) were assessed. The following were evaluated: vinyl polysiloxane in a 1-step, dual-viscosity technique (VPS Dual), polyether as monophase material (PE Mono), and vinyl siloxanether in a 1-step, dual-viscosity (VSE Dual), and monophase technique (VSE Mono). Measurements of the master model and working casts, including anteroposterior (AP) and cross-arch (XA) dimensions, were made with a measuring microscope. The simulated crown preparation was measured in mesiodistal (MDG, MDO), buccolingual (BLG, BLO), and occlusogingival dimensions (OGL, OGB). Disinfection involved immersion for 10 minutes in potassium peroxomonosulfate, sodium benzoate, tartaric acid solution, or no disinfection (control) (n=8). A multivariate GLM statistical approach (MANOVA) was used to analyze the data (alpha=.05). Pearson's correlation test was used for related dimensions. The AP and XA dimensions of working casts were larger than the master for the disinfected condition and control. Whether disinfected or not, the working dies were shorter in height (OGB, OGL), larger in the buccolingual dimension (BLO, BLG), somewhat larger in the MDO dimension, and somewhat smaller in the MDG dimension compared to the prepared tooth of the master model, resulting in an irregular or oval profile. There were significant differences among the impression systems for each dimension except AP. Differences between the disinfected and nondisinfected conditions were significant (P=.03) with respect to dimensions of the gypsum working cast, but not for dimensions of the working die (P=.97). In general, differences relative to the master were small and of minor clinical significance considering marginal gaps of crowns smaller than 150-100 mum are considered clinically acceptable. VSE monophase impressions and VSE dual-viscosity impressions demonstrated acceptable accuracy for clinical use with immersion disinfection, since the results for VSE were comparable to the results for PE and VPS materials, and the differences as compared to the master model were small.