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Background: A new elastomeric impression material which is a combination of vinyl polysiloxane (VPS) and polyether (PE) elastomers called “polyvinyl ether silicone” (PVES) has been introduced with predictable accuracy and high‑quality impressions. There is insufficient data on mechanical properties of this material. Materials and Methods: A comparative study of mechanical properties of VPS, PE, and PVES was carried out using light‑ and heavy‑body consistencies of the three materials. Three standardized stainless steel molds were made to fabricate study specimens (n = 96). The specimens were tested for elastic recovery, strain under compression, tear energy, and tensile strength (TS) using the universal testing machine. Statistical analysis was done using two‑way analysis of variance test. Results: Elastic recovery was higher in VPS as compared to other two materials. Strain under compression was higher for PE followed by PVES. Tensile energy was significantly higher in PVS while TS was higher in VPS, followed by PVES and PE. Conclusion: PVES tested was found to be more flexible with high tensile energy. This material can be preferred in cases with undercut areas favoring the removal of impressions without tear and distortion. Keywords: Elastic recovery, strain under compression, tear strength, tensile strength
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Contemporary Clinical Dentistry Volume 10 Issue 2 April-June 2019 Pages 1-182
Volume 10 / Issue 2 /April - June 2019
Spine 8 mm
203 © 2020 Contemporary Clinical Dentistry | Published by Wolters Kluwer - Medknow
The successful fabrication of restorations
largely depends on an accurate
impression from which a replica of the
intraoral structures can be precisely
created.[1,2] Elastomeric impression
materials have always been the choice
of material in xed prosthodontics, due
to inherent qualities such as reduced
marginal voids and distortion resulting in
available elastomeric materials, the vinyl
polysiloxanes (VPS) and polyethers (PEs)
are used most frequently. Advances in
elastomeric chemistries have led to the
materials which is a combination of
polyvinyl and PE called “polyvinyl ether
Few of the properties of this newly
introduced material, that is, PVES have
of ve PVES consistencies when stored
for up to 2 weeks, with and without using
Address for correspondence:
Dr. Suryakant C. Deogade,
C/o Vivek Thombre, Flat
No-301, Maharshi Gajanan
Apartment-3, Wanjari Nagar,
Nagpur - 440 003, Maharashtra,
E-mail: dr_deogade@yahoo.
Background: A new elastomeric impression material which is a combination of vinyl
polysiloxane (VPS) and polyether (PE) elastomers called “polyvinyl ether silicone” (PVES) has
beenintroduced withpredictable accuracyandhigh‑qualityimpressions.Thereis insucientdataon
mechanicalproperties ofthismaterial. Materials and Methods:Acomparative studyofmechanical
properties of VPS, PE, and PVES was carried out using light‑ and heavy‑body consistencies
of the three materials. Three standardized stainless steel molds were made to fabricate study
specimens(n = 96).The specimens were tested for elastic recovery,strainundercompression,tear
energy,and tensile strength (TS) using the universal testing machine. Statistical analysis was done
usingtwo‑wayanalysisofvariancetest.Results:Elasticrecovery was higher inVPSascompared
to other two materials. Strain under compression was higher for PE followed by PVES. Tensile
energy was signicantly higher in PVS while TS was higher in VPS, followed by PVES and PE.
Conclusion: PVES tested was found to be more exible with high tensile energy. This material
canbepreferredincases with undercut areas favoring theremovalofimpressionswithouttear and
Keywords: Elastic recovery, strain under compression, tear strength, tensile strength
Mechanical Properties of a New Vinyl Polyether Silicone in Comparison to
Vinyl Polysiloxane and Polyether Elastomeric Impression Materials
Original Article
Pragya Pandey,
Sneha Mantri1,
Abhilasha Bhasin1,
Suryakant C.
Consultant Prosthodontist,
Clove Dental, Jaipur, Rajasthan,
1Department of Prosthodontics
and Crown and Bridge,
Hitkarini Dental College and
Hospital, Jabalpur,
Madhya Pradesh, 2Department
of Prosthodontics and Crown
and Bridge, Government Dental
College and Hospital, Medical
Campus, Medical Square,
Nagpur, Maharashtra, India
How to cite this article: Pandey P, Mantri S,
Bhasin A, Deogade SC. Mechanical properties of a
new vinyl polyether silicone in comparison to vinyl
polysiloxane and polyether elastomeric impression
materials. Contemp Clin Dent 2019;10:203‑7.
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a standard disinfection procedure. They
found that the PVES was dimensionally
stable for clinical use after disinfection for
30 min in glutaraldehyde and storage for
containing nanollers with conventional
VPS and PE impression materials. They
found that all materials were hydrophilic,
especially PVES and PE which recorded
the highest wettability. VPS containing
and PVS recorded the higher exibility
thanVPS containingnanollers,whileVPS
the dimensional stability and accuracy
of PE, VPS, and PVES materials and
observed that PVES yielded more accurate
impressions than those of VPS and PE.
Nassar etal.[8] compared the advancing
contact angle of water on the surface of
such as VPS, PVES, and PE. They found
that set VPS was more hydrophilic than
PVES and PE. Lakshmi etal.[9] evaluated
Access this article online
DOI: 10.4103/ccd.ccd_324_18
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Pandey, et al.: Mechanical properties of a new elastomeric impression material
the compatibility of VPS, PVES, and PE impression
showed highest bond strength with acrylic resin tray than
bond strength with all the three impression materials.
However, PVES showed higher bond strength than VPS.
Tabeshetal.[10] comparedtheimplantimpressionprecision
techniques. They concluded that PE is recommended for
directtechniquewhilePE and PVES arerecommendedfor
indirect technique. Recommended technique for PVES is
studies[11,12] stated that PVES monophase impressions and
PVES dual‑viscosity impressions display the acceptable
accuracyforclinicalusewith immersion disinfection since
the results for PVES were comparable to the results for
representativePE andVPSmaterials.
For a successful clinical outcome, an impression material
should inherently have desirable physical as well as
tensile strength (TS) ensure that the impression material can
withstand the various stresses upon removal of impression
from the mouth while maintaining dimensional stability and
integrity.[14] Elastic recovery is the ability of the impression
material to recover after deformation.[15] This deformation
is dependent on the depth of the undercut and is one of the
most important properties in assessing the suitability of an
impression material for clinical use. Strain in compression is
ameasureofthe exibility/stinessofmaterialsandindicates
whether the polymerized impression can be removed from
the mouth and have adequate stiness in the more exible
portions of impressions so that the poured gypsum cast can
be removed from the impression without fracture.[16] TR
indicates the ability of a material to withstand tearing in thin
interproximal and undercut areas and in the depth of the
gingivalsulcus, whileretrievalof impression.[17,18]
TS reects the maximum stress; a material can bear
under tension before the breaking limit. Maximum tensile
removal forces of impression materials have been shown
to be greater than maximum compressive seating forces,
especially when materials are stretched in tension as
they are pulled from undercuts, sharp line angles, and
interproximal spaces.[19‑21] The purpose of this in vitro
study was to comparatively evaluate the above‑mentioned
mechanical properties of VPS, PE, and new PVES
elastomeric impression materials. Null hypothesis stated
that there was no signicant dierence in the mechanical
propertiesof theimpressionmaterials andconsistencies.
Materials and Methods
The materials tested in the study were VPS (Flexceed, GC
3MDeutschland GmbH, Germany), and VPS (EXA’lenceTM,
GC Dental Products Corp., Japan). Light‑ and heavy‑body
consistencieswereusedfor all threematerials.Foreachtype
of material, 32 specimens were made and divided into four
three standardized stainless steel (SS) molds were made for
three variable forms of specimens for dierent mechanical
properties to be tested. To fabricate rectangular specimens
forTE,arectangularSSmoldof 75 mm × 25 mm × 1 mm
dimension was made. For studying TS and K%, a 2 mm
wide and 1.5 mm thick dumbbell‑shaped mold with an
inner bar was made. A 25‑mm long section of the inner bar
was delineated by four semicircular notches in the mold.
For analyzing E%, a hollow cylindrical mold with internal
diameterof15mmandheight20mmwas made [Figure 1].
For each type of material, 32 specimens were made and
divided into four subgroups (n = 8) according to the
propertiestobetested[Figure 2].
Elastic recovery was tested according to ISO4823. The
then the load was released and after 2 min, the change
in length (DL) was measured. For measuring strain in
compression,loadwas added into the specimens gradually
load was maintained for 30 s and the DL was measured.
Tear energy (TE)/Tear strength was measured using
speciedbyWebberand Ryge.Usingasharp razor blade,
a 50‑mm slit was made, producing trouser leg‑shaped
specimens (12.5 mm wide). The legs of the specimens
were placed vertically in opposite directions. The grip
separation speed was 20 mm/min. When testing TE, the
tearcandeviatefromthe central axis of thetestspecimen,
and then the calculation for the observed extension ratio
would not be accurate, so such specimens were discarded.
TS was measured following ASTMD412 (Test Method)
on dumbbell‑shaped specimens. Three measurements (for
thickness and width, respectively) were made, 1 at
the center and 1 at each reduced end.  The rate of
grip separation was 50 mm/min. TS was recorded and
calculatedbysoftware(Series IX,Version 7.27.00, Instron
Corp). All the tests were conducted using a screw‑driven
Universal Testing Machine (Model Mini4, Instron corp)
usingtwo‑way analysisofvariance (ANOVA).
Table 1 lists the mean and standard deviations of tested
properties. For all the tested materials, K% was ≥98%.
E% was signicantly higher in PE material. Overall, the
light‑body material had signicantly lower TE and TS
than heavy‑body materials. TE was highest with PVES
and TS was highest with VPS material. ANOVA shown
in Table 2 describes that interaction between the material
and consistencies had statistically signicant inuence on
the properties tested. Pearson’s correlation coecient was
stronglypositive betweenK%andTS[Table3].
Contemporary Clinical Dentistry | Volume 10 | Issue 2 | April-June 2019 204
Pandey, et al.: Mechanical properties of a new elastomeric impression material
The viscoelastic properties of the elastomeric impression
materialsplay a major role in their successfulapplications
as high accuracy impression materials.[13] The amount
of permanent deformation attributed to the dashpot is
dictatedby the duration of tension or compressionexerted
on the material.[22] An arbitrary 0.4% deformation has
been estimated to be the clinically signicant deformation
Inthe present study,theviscoelastic/mechanical properties
of VPS, PE, and PVES were compared and correlated.
The null hypothesis that there is no dierence in the
mechanical properties of the impression materials and
consistencies tested was rejected. Elastic recovery is
important in determining the accuracy of an impression
was induced in an elastomeric impression material when
removing it from structures with undercuts 1 mm high
and deep.[25] de Araujo etal.[26] recorded the relationship
between the induced and permanent deformation of
elastomeric dental impression materials during and after
setting.Theyreported the meanrecoverytimerangesfrom
met the requirement of ISO4823, which requires ≥96.5%
recovery.[27]The PE and PVES had lower elastic recovery
than VPS and showed statistically signicant dierence.
The greater elastic recovery of PVS is attributed to the
excellent cross‑linking with the hydride group between
the polymeric chains.[13] However, among consistencies,
heavy body had higher K% than light body, due to the
presence of llers in the heavy body.These ndings were
inagreementwitha studybyLuetal.[14]in which silicone
materials showed greater recovery than PE. Inoue etal.[28]
have demonstrated that there was increase in permanent
deformation in thinner sections of set material than the
thicksections whensubjectedto shear.
The results of the present study showed that all the
tested values for E% were within the range required by
ISO4823(0.8%–20%forlight‑bodymaterial and 2%–20%
forheavy‑body material).[27]TheVPSwas more rigid than
Table 1: Elastic recovery, strain in compression, tear energy, and tensile strength of tested impression materials
K% 98.49±0.34 99.81±0.15 98.07±0.63 98.59±0.07 98.32±0.67 98.75±0.63
E% 5.66±0.25 3.38±0.24 9.22±0.13 8.41±0.86 8.16±0.95 7.41±0.48
TE(J/m2) 596.25±51.65 669.00±19.10 685.75±26.11 749.75±29.40 746.50±49.65 987.50±5.80
TS(MPa) 3.49±0.13 5.60±0.54 1.80±0.36 2.40±0.42 2.55±0.45 3.52±0.34
Table 2: Summary of two‑way analysis of variance
Material 6.373 0.008* 120.099 0.000*(<0.001) 95.462 0.000*(<0.001) 79.301 0.000*(<0.001)
Consistency 14.847 0.001* 29.232 0.000*(<0.001) 80.648 0.000*(<0.001) 58.794 0.000*(<0.001)
Interaction 3.120 0.044* 4.514 0.026*(<0.05) 16.874 0.000*(<0.001) 8.066 0.003*(<0.001)
Table 3: Correlation between the mechanical properties
Correlation between Pearson’s correlation coecient P
K%andE% −0.666
K%andTE −0.016
K%andTS 0.746
E%andTE 0.319
E%andTS −0.898
TEandTS −0.056
205 Contemporary Clinical Dentistry | Volume 10 | Issue 2 | April-June 2019
Pandey, et al.: Mechanical properties of a new elastomeric impression material
the PE and PVES. However, the newer generation of PE
has been incorporated with more amount of plasticizes,
renderingitmoreexible.[29]According to Jamani etal.[30],
rigidity of material is always greater when tested 30 min
after the start of mix than when tested at the setting time.
This is because the polymerization continues after the
settingtime.[30]This wassupportedbyHarcourtwho found
that leaving the impression in the mouth beyond setting
time led to an in increase in rigidity.[31] Furthermore,
E% was correlated with K%, TE, and TS. The exible
llers, or more plasticizer, so they would be expected to
be weaker than the stier materials and more easily torn.
Elastic recovery and strain in compression were inversely
correlated. When developing materials, a balance should
be chosen that maximizes the elastic recovery, while
maintainingexibility inanacceptablerange.[32]
TEindicates the ability of a material to withstand tearing
inthin interproximalareasandinthedepthofthegingival
sulcus. Tear strength is inuenced by the chemical
composition, consistency, and manner of removal of
material. A rapid rate of force application during removal
methods proposed by the American National Standard
Institution/American Dental Association specication No.
19 or ISO4823 to determine the tear strength.[33] Rivlin
and Thomas[34] developed a simple extension tear test,
currentlyusedtostudy the tear strength.The method was
later adapted by Webber and Ryge as “Trouser tear test.”
In the present study, TE was measured by the “Trouser
tear test” developed for thin sections of elastomeric
materials.[24] Results showed that there was statistically
signicantdierenceinTEamongallthree materials.The
TE of PVES and PE was higher than the VPS. Braden
and Elliot. concluded that PE had shear modulus four
times high as that of addition PVS, and there is direct
relationship between the shear modulus and diculty
encounteredin removinganimpressionfromthemouth.[35]
StatisticalanalysisshowedTSofVPSwashigherthan PE
andPVES(mean,TS = 3.49). However,PVESwasbetter
thanPEinthis regard. Thisresultwasinaccordance with
asimilarstudybyLu,[22]in whichTSofadditionsilicones
was greater than the PE. Lawson etal.[36] compared the
elastic recovery from tensile strain for 5‑VPS materials.
This study demonstrated that elastomeric impression
materials permanently deform following 50% and 100%
tensile strains. The variation in tensile elastic recovery
among VPS materials is related to components of their
composition, including the proportions of base silica,
copolymer, ller, and chain extenders.[35,36] Thus, the
selection of an impression material for a particular
application should be based on property data, rather
than on the type and class of the elastomeric impression
Thepresentstudywasconductedinan in vitro environment.
Although the impressions were made of standardized SS
dies, the intraoral conditions could not be simulated to
determine the acceptable range of viscoelastic parameters,
a clinical investigation should be undertaken, in which
several materials of known modulus should be used for
Within the limitations of this study, it could be concluded
that the newer material PVES tested was found to be
more exible with high‑tensile energy. This material can
be preferred in cases with undercut areas, favoring the
removalof impressionswithouttear anddistortion.
Figure 2: Grouping of specimens
Contemporary Clinical Dentistry | Volume 10 | Issue 2 | April-June 2019 206
Pandey, et al.: Mechanical properties of a new elastomeric impression material
Financial support and sponsorship
Conicts of interest
Thereare noconictsof interest.
1. Chee WW, Donovan TE. Polyvinyl siloxane impression
2. Chai J, Takahashi Y, Lautenschlager EP. Clinically relevant
mechanical properties of elastomeric impression materials. Int J
3. Rubel BS. Impression materials: A comparative review of
impression materials most commonly used in restorative
dentistry.DentClin NorthAm2007;51:629‑42,vi.
4. Shetty RM, Bhandari RG, Mehta D. Vinyl poly siloxane ether:
A breakthrough elastomeric impression materials. World J Dent
5. Nassar U, Flores‑Mir C, Heo G, Torrealba Y. The eect of
prolonged storage and disinfection on the dimensional stability
of 5 vinyl polyether silicone impression materials. J Adv
6. ShetaaMS,El‑Shorbagyb ZA,Abdel Karima UM,Abd‑Allab S.
Laboratory comparative study of wettability, dimensional
changes,exibilityandtear resistance of two recent elastomeric
impressionmaterials.TantaDentJ 2017;14:89‑95.
7. PandeyA,MehtraA.Comparative studyofdimensionalstability
and accuracy of various elastomaric materials. J Dent Med Sci
8. NassarU, TavoossiF,PanYW,Milavong‑ViravongsaN, HeoG,
Nychka JA. Comparison of the contact angle of water on set
elastomericimpression materials.J CanDentAssoc2018;84:i6.
9. Lakshmi CB, Umamaheswari B, Devarhubli AR, Pai S,
Wadambe TN. An evaluation of compatibility of three dierent
impressionmaterialstothree dierent tray acrylicmaterialsusing
trayadhesives:An in vitro study.IndianJDentSci2018;10:37‑41.
10. Tabesh M, Alikhasi M, Siadat H. A comparison of implant
impression precision: Dierent materials and techniques. J Clin
ExpDent 2018;10:e151‑7.
11. WadhwaniCP,JohnsonGH,LepeX,RaigrodskiAJ.Accuracyof
newly formulated fast‑setting elastomeric impression materials.
JProsthet Dent2005;93:530‑9.
12. Kang AH, Johnson GH, Lepe X, Wataha JC. Accuracy of a
reformulated fast‑set vinyl polysiloxane impression material
usingdual‑arch trays.J ProsthetDent2009;101:332‑41.
13. Shen C. Impression materials. In:Anusavice KJ, editor. Philips’
Science of Dental Materials. 11th ed. St. Louis: Elsevier; 2003.
14. Lu H, Nguyen B, Powers JM. Mechanical properties of
3 hydrophilic addition silicone and polyether elastomeric
impressionmaterials. JProsthet Dent2004;92:151‑4.
15. AnusaviceKJ,editor.Mechanical properties of dentalmaterials.
In: Philips‘ Science of Dental Materials. 11th ed. Philadelphia,
16. Donovan TE, Chee WW. A review of contemporary impression
materials and techniques. Dent Clin North Am 2004;48:vi‑vii,
17. Cohen BI, Pagnillo MK, Musikant BL, Deutsch AS. Tear
strength of four irreversible hydrocolloid impression materials.
JProsthodont 1998;7:111‑3.
18. KeckSC,DouglasWH.Tearstrengthofnon‑aqueousimpression
materials.J DentRes 1984;63:155‑7.
19. Chai J, Takahashi Y, Lautenschlager EP. Clinically relevant
mechanical properties of elastomeric impression materials. Int J
20. Sandrik JL, Vacco JL. Tensile and bond strength of
putty‑wash elastomeric impression materials. J Prosthet Dent
21. Klooster J, Logan GI, Tjan AH. Eects of strain rate on
the behavior of elastomeric impression. J Prosthet Dent
22. Inoue K, Wilson HJ. Viscoelastic properties of elastomeric
impression materials. II: Variation of rheological properties
with time, temperature and mixing proportions. J Oral Rehabil
23. CraigRG. Reviewofdentalimpressionmaterials.AdvDentRes
24. Salem NS, Combe EC, Watts DC. Mechanical properties of
25. JörgensenKD.Anewmethodofrecordingtheelasticrecoveryof
dentalimpression materials.Scand JDentRes1976;84:175‑82.
26. de Araujo PA, Jorgensen KD, Finger W. Viscoelasticproperties
of setting elastomeric impression materials. J Prosthet Dent
27. International Organization for Standardization 4823 for
ElastomericImpressionMaterials.InternationalOrganization for
28. Inoue K, Wilson HJ. Viscoelastic properties of elastomeric
impression materials. I. A method of measuring shear modulus
andrigidity duringsetting. JOralRehabil1978;5:89‑94.
29. Chee WW, Donovan TE. Polyvinyl siloxane impression
30. Jamani KD, Harrington E, Wilson HJ. Rigidity of elastomeric
impressionmaterials. JOral Rehabil1989;16:241‑8.
31. Harcourt JK. A review of modern impression materials. Aust
DentJ 1978;23:178‑86.
32. Webber RL, Ryge G. The determination of tear energy of
extensible materials of dental interest. J Biomed Mater Res
33. American Society for the Testing of Materials. Standard test
Methods for Vulcanized Rubber and Thermoplastic Elastomers
Tension[ASTM D412‑98a]. WestConshohocken, PA:American
National Standards Institute, Annual Book ofASTM Standards;
2002.p. 43‑55.
34. RivlinRS, ThomasAG.Ruptureof rubber.Characteristicenergy
fortearing. JPolym Sci1953;10:291.
35. Braden M, Elliott JC. Characterization of the setting process of
siliconedental rubbers.J DentRes1966;45:1016‑23.
36. Lawson NC, Burgess JO, Litaker MS. Tensile elastic
recovery of elastomeric impression materials. J Prosthet Dent
37. Sneed WD, Miller R, Olson J. Tear strength of ten elastomeric
impressionmaterials. JProsthet Dent1983;49:511‑3.
38. Braden M. Characterization of the rupture properties of
impressionmaterials. DentPract 1963;14:67‑9.
207 Contemporary Clinical Dentistry | Volume 10 | Issue 2 | April-June 2019
Full-text available
Background Restoring vital teeth with indirect restorations may threaten dental pulp integrity. However, the incidence of and influential factors on pulp necrosis and periapical pathosis in such teeth are still unknown. Therefore, this systematic review and meta-analysis aimed to investigate the incidence of and influential factors on pulp necrosis and periapical pathosis of vital teeth following indirect restorations. Methods The search was conducted in five databases, using MEDLINE via PubMed, Web of Science, EMBASE, CINAHL, and Cochrane Library. Eligible clinical trials and cohort studies were included. The risk of bias was assessed using Joanna Briggs Institute’s critical appraisal tool and Newcastle–Ottawa Scale. The overall incidences of pulp necrosis and periapical pathosis following indirect restorations were calculated using a random effects model. Subgroup meta-analyses were also performed to determine the potential influencing factors for pulp necrosis and periapical pathosis. The certainty of the evidence was assessed using the GRADE tool. Results A total of 5,814 studies were identified, of which 37 were included in the meta-analysis. The overall incidences of pulp necrosis and periapical pathosis following indirect restorations were determined to be 5.02% and 3.63%, respectively. All studies were assessed as having a moderate-low risk of bias. The incidence of pulp necrosis following indirect restorations increased when the pulp status was objectively assessed (thermal/electrical testing). The presence of pre-operative caries or restorations, treatment of anterior teeth, temporization for more than two weeks, and cementation with eugenol-free temporary cement, all increased this incidence. Final impression with polyether and permanent cementation with glass ionomer cement both increased the incidence of pulp necrosis. Longer follow-up periods (> 10 years) and treatment provided by undergraduate students or general practitioners were also factors that increased this incidence. On the other hand, the incidence of periapical pathosis increased when teeth were restored with fixed partial dentures, the bone level was < 35%, and the follow-up was > 10 years. The certainty of the evidence overall was assessed as low. Conclusions Although the incidences of pulp necrosis and periapical pathosis following indirect restorations remain low, many factors affect these incidences that should thus be considered when planning indirect restorations on vital teeth. Database registration PROSPERO (CRD42020218378).
Full-text available
Background This study aimed to compare the dimensional accuracy, hydrophilicity and detail reproduction of the hybrid vinylsiloxnether with polyether and polyvinylsiloxane parent elastomers using modified digital techniques and software. This was done in an attempt to aid in solving the conflict between the different studies published by competitive manufacturers using different common manual approaches. Methods A polyether, polyvinylsiloxanes and vinyl polyether silicone hybrid elastomeric impression materials were used in the study. Dimensional accuracy was evaluated through taking impressions of a metallic mold with four posts representing a partially edentulous maxillary arch, that were then poured with stone. Accuracy was calculated from the mean of measurements taken between fixed points on the casts using digital single-lens reflex camera to produce high-resolution digital pictures for all the casts with magnification up to 35×. Hydrophilicity was assessed by contact angle measurements using AutoCAD software. The detail reproduction was measured under dry conditions according to ANSI/ADA Standard No. 19 and under wet conditions as per ISO 4823. A metallic mold was used with three V shaped grooves of 20, 50, and 75 µm width. Specimens were prepared and examination was made immediately after setting using digital images at a magnification of 16×. Results The hybrid impression (0.035 mm) material showed significantly higher dimensional accuracy compared to the polyether (0.051 mm) but was not as accurate as the polyvinyl siloxane impression material (0.024 mm). The contact angles of the hybrid material before and after setting was significantly lower than the parent materials. With regard to the detail reproduction, the three tested materials were able precisely to reproduce the three grooves of the mold under dry conditions. Whereas, under wet conditions, the hybrid material showed higher prevalence of well-defined reproduction of details same as polyether but higher than polyvinylsiloxane that showed prevalence of details with loss of sharpness and continuity. Conclusions The digital technique used could be a more reliable and an easier method for assessment of impression materials properties. The hybridization of polyvinyl siloxane and polyether yielded a promising material that combines the good merits of both materials and overcomes some of their drawbacks.
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This study investigates 2 polyethers (PE), 2 polyvinylsiloxanethers (VXSE), and 10 polyvinylsiloxanes (PVS), seven of which had a corresponding light-body consistency and seven of which had a corresponding heavy-body consistency. Each light-body elastomer underwent a flowability test using the shark fin method 20, 50, and 80 s after mixing. The tear strength test DIN 53504 was used after setting the time (T0). Next, 24 h later (T1), hydrophilicity testing was used with static contact angles in water drops during polymerization (20, 50, and 80 s, as well as after 10 min). The heavy-body elastomers underwent shark fin testing with a corresponding light-body material at 50 and 80 s after mixing. The results of light-body testing were combined in a score to describe their performance. The highest differences were detected within flowability in shark fin heights between PE and a PVS (means of 15.89 and 6.85 mm) within the maximum tear strengths at T0 between a PVS and PE (3.72 and 0.75 MPa), as well as within hydrophilicity during setting between VXSE and a PVS (15.09° and 75.5°). The results indicate that VSXE and novel PVS materials can significantly compensate shortcomings in PE towards tear strength and hydrophilicity, but not flowability.
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Objectives This study aimed to compare the accuracy of conventional and digital impressions based on the fit of produced three-unit fixed partial dentures (FPDs) in vivo and the trueness and precision of both impression techniques. Materials and methods Twelve patients received a conventional polyether impression (group C, control, n=12) and a digital impression with CS3500 (group D, test, n=12) for each participant. Monolithic multilayer zirconia FPDs were fabricated, and the internal and marginal fit were assessed using the replica technique. Trueness and precision of both impression methods were assessed in vitro. A master model was used to create a reference scan. The master model received conventional impressions (group C, control, n=5) and digital impressions (group D, test, n=5). The virtual models of both groups were superimposed over the reference scan (5 superimpositions) using a three-dimensional (3D) processing software, and the 3D deviations were measured and averaged to obtain trueness value. For precision, the virtual models of each group were superimposed over each other (10 superimpositions) and the average deviation value was calculated. The data were analyzed using one-tailed Mann–Whitney U test at P ≤ 0.05. Results Group D resulted in a significantly better marginal and internal fit (30.91±15.15 and 30.86±13.57 μm for group D and 40.02±19.50 and 41.86±18.94 μm for group C). The mean values of trueness and precision for conventional and digital techniques were comparable (trueness: 62.8±5.45 and 62.72±12.01 μm and precision: 56.47±27 and 60.9±14.5 μm, respectively). Conclusions No significant difference was found between conventional and digital impressions in 3D datasets accuracy. In addition, both techniques resulted in FPDs with an acceptable clinical fit. However, the FPDs fabricated using the digital technique displayed better internal and marginal fit. Clinical relevance The applied impression technique as well as the computer-aided processing of the produced virtual models can significantly affect the fit of the final restoration. Direct digital impression is recommended over conventional impression for fabricating accurate monolithic zirconia 3-unit FPDs. Trial registration This clinical trial was retrospectively registered on August 11, 2020, in the Pan African Clinical Trial Registry database, and the number for the registry is PACTR202008685699453.
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Background: Impressions are an integral part of prosthodontics. Elastomeric impression materials are the impressions materials of choice in fixed prosthodontics for its better surface detail reproduction. Out of the elastomers available, vinyl polysiloxane represents the state of art impression material in prosthodontics, but even these materials cannot give an accurate reproduction of the tissues if there is separation of impression materials from the tray which may results in a distorted impression leading to poor final restorations made from such impressions. Hence, tray adhesives need to be applied to the tray to obtain an accurate and consistent impression. The purpose of the study was to evaluate the compatibility of three different impression materials to three different tray acrylic materials using tray adhesive, by determining the tensile bond strength. Materials and Methods: Two acrylic discs were utilized to make one impression sample of 3 mm thickness. The dimension of each acrylic disc was 2 mm in thickness and 2 cm in diameter. Specimens were made using a standard stainless steel die of the above-mentioned dimensions. A total of 135 specimens were prepared which included 15 samples in each category of nine groups. The samples were subjected to tensile bond strength testing using the universal testing machine and the values were recorded. All the values were subjected for statistical analysis. Results: Impregum (3M) specimens had demonstrated the highest tensile bond strength value (51.60N). Statistical analysis was done using Tukey's post hoc test and one-way ANOVA. Highly Statistical significant results were evident in Impregum (3M) and Indentium, as the P = 0.00. Conclusion: In this study Impregum (3M), specimens had highest tensile bond strength values compared to the other Groups followed by Indentium.
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Background Precision 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 Methods A 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. Results With 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. Conclusions On 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.
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PURPOSE Vinyl polyether silicone (VPES) has a different composition from other elastomeric impression materials as it combines vinyl polysiloxane (VPS) and polyether (PE). Therefore, it is important to study its properties and behavior under different test conditions. This study investigated the dimensional stability of 5 VPES consistencies when stored for up to 2 weeks, with and without using a standard disinfection procedure. MATERIALS AND METHODS 40 discs of each VPES consistency (total 200) were made using a stainless steel die and ring as described by ANSI /ADA specification No. 19. 20 discs of each material were immersed in a 2.5% buffered glutaraldehyde solution for 30 minutes. Dimensional stability measurements were calculated immediately after fabrication and repeated on the same discs after 7 and 14 days of storage. The data was analyzed using two-way ANOVA with a significance level set at α = 0.05. RESULTS The discs mean contraction was below 0.5% at all test times ranging from 0.200 ± 0.014 to 0.325 ± 0.007. Repeated measures ANOVA showed a statistically significant difference after 2-week storage between the disinfected and non-disinfected groups (P < .001). Although there was no statistically significant difference between the materials at the time of fabrication, the contraction of the materials increased with storage for 1 and 2 weeks. CONCLUSION The dimensional changes of VPES impression discs after disinfection and prolonged storage complied with ANSI/ADA standard. The tested VPES impression materials were dimensionally stable for clinical use after disinfection for 30 minutes in glutaraldehyde and storage for up to 2 weeks.
Purpose: The hydrophilicity of some elastomeric impression materials has not been fully established. The purpose of this study was to measure and compare the advancing contact angle of water on the surface of several set elastomeric impression materials. Materials and methods: We tested various consistencies of vinyl polysiloxane (VPS; Imprint 4) and vinyl polyether silicone (VPES; EXA'lence) with a polyether (PE; Impregum Soft) control. Impression discs (25.07 mm) were made using a metal die and ring. Deionized ultra-filtered water was placed on each disc and contact-angle measurements were made at 0, 15, 30, 45 and 60 s using a video contact angle drop shape analysis machine. The data were analyzed using repeated ANOVA and a post-hoc test with Bonferroni correction. Results: VPS contact angles reached a mean of 10.1° ± 0.2° at 60 s vs. 40.7° ± 0.1° for VPES. Overall, VPS contact angles were smaller than those for VPES at all measured times. However, heavy and super quick heavy VPS had much higher contact angles at 0 s compared with other VPS consistencies. There was a significant difference in contact angles between VPS and VPES (mean difference 33.9°, p < 0.05) and between VPS and PE (mean difference 32.8°, p < 0.05) but not between VPES and PE (P = 0.196). VPS heavy and super quick heavy were significantly different from other VPS materials (p < 0.05), but not from each other (p = 1.00). Conclusions: Set VPS is more hydrophilic than VPES. Contact-angle values of VPS indicated super hydrophilicity. VPES was hydrophilic, with measurements similar to the PE control. Thus, VPS impression materials may be excellent in terms of spreading and copying wet surfaces.
A meticulous impression is paramount for a precision fit of indirect restoration. Unfortunately, for many clinicians, making an impression for fixed prostheses is one of the challenging aspects in restorative dentistry. Advances in elastomeric chemistries have given birth to a new generation of impression materials: a combination of a polyvinyl and a polyether impression material, called vinyl siloxane ether. The purpose of this article is to explore the new impression material which is effective and efficient to obtain predictable, accurate, high quality impressions in dental practice. How to cite this article Shetty RM, Bhandari GR, Mehta D. Vinyl Polysiloxane Ether: A Breakthrough in Elastomeric Impression Material. World J Dent 2014;5(2):134-137.
A criterion for tearing of test-pieces cut from thin sheets of a natural rubber vulcanizate, similar in form to the Griffith criterion for spreading of a crack, is formulated. This criterion involves a characteristic energy for tearing which is independent of the shape of the test-piece and of the disposition of the cut. It is shown how this characteristic energy can be found experimentally for a particular vulcanizate and used to predict the force required to tear test-pieces of the vulcanizate.