Aquasil - Dentsply

Technical Manual
Aquasil
TM
A new Direction in Impressive Dentistry
2000-01-17
Individual Attention Only
Table of Contents
1
Introduction
4
2
Description
4
3
4
2.1 Light Body Materials
5
2.2 Monophase Materials
5
2.3 Heavy Body Materials
5
2.4 Putty Material
6
History of Vinyl Polysiloxanes and Polyether Impression Materials
3.1 Impression Material Timeline
6
3.2 Aquasil Quadrafunctional Hydrophilic Impression Material
7
3.2.1 Material Improvements
7
3.2.2 Improvements of the Application System
8
Chemistry of Polyethers, A-Silicones and Aquasil
9
4.1 Polyether
9
4.1.2 Main Problems
9
10
4.2.1 Main Features
10
4.2.2 Problem:
11
4.3 Aquasil
6
9
4.1.1 Main Features
4.2 Traditional Addition Curing Silicones (A-Silicones)
5
6
11
4.3.1 Main Features
12
4.3.2 Main Differences to traditional A-Silicones
12
Physical Aspects
14
5.1 Development of Hydrophilicity
14
5.2 Enhanced Shore A Hardness
15
5.3 Enhanced Tear Strength
16
5.4 Rheological Aspects of the Aquasil Products
19
5.4.1 Introduction
19
5.4.2 Experimental Data
21
5.4.3 Setting reaction
24
Handling Aspects of the new Cartridge System
26
6.1 Light Bodies
26
2
6.2 Heavy Body and Monophase
27
7
Material Scientific Investigations
28
8
Clinical Evaluation of Aquasil Impression Materials
29
8.1 Clinical Evaluation of Aquasil Monophase in daily Practice
29
8.2 Clinical Rating of Aquasil Monophase and Aquasil LV
30
8.3 Clinical Evaluation of K-0084 (Aquasil) Putty and ULV in the Double Mix Technique 30
8.3.1 Controlled clinical study
30
8.3.2 Re-evaluation of Aquasil Soft Putty and Aquasil ULV for the double mix technique
32
8.4 Clinical Evaluation of K-0084 (Aquasil) Putty and ULV for the Putty / Wash Technique
32
9
Main Investigator: Prof. Dr. E. Beetke, University of Rostock
32
Directions for Use
33
9.1 Description and technical Data
33
9.1.1 Indication for Use
33
9.1.2 Contraindications
34
9.1.3 Precautions and Warnings
34
9.1.4 Interactions with Other Materials
34
9.1.5 Preparations
35
9.1.6 Disinfection
36
9.1.7 Tray Cleaning Instruction
36
9.1.8 Dispenser Cleaning Instruction
37
9.1.9 Casting and Electroplating
37
9.1.10 Technical Data
37
9.1.11 Storage
38
9.1.12 Batch Number and Expiry Date
38
9.2 Step-by-Step Instructions
39
9.2.1 Single Phase Technique
39
9.2.2 Double Mix Technique
40
9.2.3 Putty / Wash Technique
42
10 Literature List
44
3
1 Introduction
The quadrafunctional hydrophilic Aquasil chemistry (patent applied) combines a cross-linked
polymer web with a proprietary surface active ingredient. The polymer web provides
exceptional tear strength, and the proprietary surfactant has a wetting ability equivalent to
polyethers. This unique modified vinyl siloxane chemistry provides surface detail in a moist
environment unmatched by traditional impression materials.
In addition to these improved material properties, the Aquasil system is offered in an improved cartridge system that enables the dentist to apply the syringe material directly to the
preparation with a remarkable improvement of handling and reduce of waste.
The new Aquasil DECA system is compatible with the today existing automatic mixing
devices.
2 Description
The Aquasil system is the synthesis of the favourite properties of both polyethers and existing
addition curing silicones. It offers the advantages of a polyether, i.e. it is hydrophilic during
impression taking while offering the viscosity and ”snap set” characteristics that appeal to the
polyether user. It also has all the advantages of a traditional vinyl polysiloxane such as easier
removal from the mouth, no taste, no smell, and the ability to be disinfected/sterilised. The
Aquasil system offers something that neither of these categories have been able to achieve
sufficiently, namely very high tear strength.
As a system of materials for all specialities of taking dental impressions, the new Aquasil
brand is divided into different consistencies each suitable for a special technique of the
dentist depending on the various clinical conditions.
4
2.1 Light Body Materials
Light Body materials are suitable for taking impressions in combination with a tray material in
both the double mix technique (single-step – two-phase) and the putty / wash technique (two
steps - two-phase).
To allow direct application on to the preparation the Aquasil light bodies are offered in 25 ml
cartridges for use in the AutoMix 25. Because of the various clinical situations with different
requirements the syringe materials are provided in two consistencies:
• Low Viscosity (Aquasil LV)
• Ultralow Viscosity (Aquasil ULV)
2.2 Monophase Materials
Monophase materials are suitable for taking impressions with a single material in the singlestep single-phase technique and optionally as a tray material in combination with a
syringeable Light Body in the single-step two-phase technique.
Aquasil Monophase FS has been developed for different two application versions. The 1:1
(per volume) cartridge version in 75 ml double chambered cartridges for the use in AutoMix
75 and the 4.55:1 (per volume) Aquasil DECA version for the use in automatic mixing
devices.
2.3 Heavy Body Materials
Heavy Body materials are suitable for taking impressions as a tray material in combination
with a syringeable Light Body material either in the two-step two-phase technique (putty /
wash) or in the single-step two-phase (double mix) technique.
Aquasil Heavy FS has been developed in two different application versions. The 1:1 (per
volume) cartridge version in 75 ml double chambered cartridges for the use in AutoMix 75
and the 4.55:1 (per volume) Aquasil DECA version for the use in automatic mixing devices.
5
2.4 Putty Material
Putty materials are suitable for taking impressions in combination with a syringeable
cartridge material in both the single-step two-phase (double mix) and the two-step two-phase
(putty / wash) technique.
3 History of Vinyl Polysiloxanes and Polyether Impression
Materials
3.1 Impression Material Timeline
rubber base
1940
polyether
1960
Aquasil
1980
1950
2000
1970
1990
condensation
addition reaction
silicones
silicones
1950s - Rubber Base (Polysulfides)
Advantages:
Disadvantages:
Good wettability
High permanent deformation
Good detail
Unpleasant taste & odour
Easy to remove
Must pour within an hour
Long set time (8-10 minutes)
1960s - C-Silicones
Advantages:
Disadvantages:
Good detail
Shrinkage on setting
Fairly accurate
Shrinkage on storage
Must pour within an hour
6
1972 - Polyethers
Advantages:
Disadvantages:
Good wettability during work time
High permanent deformation
Good dimensional accuracy
Shrinkage on storage
Good detail
Unpleasant taste & odour
Hard to remove
Swells in disinfecting bath
1976 - A-Silicones
Advantages:
Disadvantages:
Good detail
Sulphur products inhibit set
Good dimensional accuracy
Hydrophilicity has to be generated by
Good resistance to deformation
surfactants
3.2 Aquasil Quadrafunctional Hydrophilic Impression Material
3.2.1 Material Improvements
3.2.1.1 Combination of the Benefits of both Polyethers and Addition Curing Silicones
• wettability as good as polyether achieved by a new, more effective surfactant
• no bad taste or odour
• good dimensional accuracy
• good resistance to deformation
• good reproduction of detail
• no swelling or shrinkage
• ability to be disinfected/sterilised
7
3.2.1.2 Improvements neither achieved by Polyethers nor by A-Silicones
• high tear strength achieved by a higher network density in the set elastomer
• rheological characteristics can be adjusted from Ultralow Viscosity Light Body to very high
consistency Putty materials which enables the dentist to use the ideal material for each
clinical situation.
3.2.2 Improvements of the Application System
The Light Bodies are provided in a new 25 ml cartridge system which offers the dentists
additional benefits:
• better handling because the material can be released directly onto the preparation
• reduced force during release achieved by better ergonomics
• reduced waste
The Monophase and the Heavy Body are provided in two different versions: as a twocomponent 1:1 (base/cat., volume ratio) system in a new 75 ml cartridge system and as a
4.5:1 (base/cat, volume ratio) Aquasil DECA system in the foil package. The cartridge has
optimised ergonomics which reduces the extrusion force significantly leading to improved
handling properties. In contrast to alternative volumes (48 ml or 50 ml) the volume of 75 ml in
most cases is sufficient material for two full arch impressions. The cartridges have to be
extruded manually with an optimised cartridge gun. The Aquasil DECA system is mixed
automatically by the use of established automatic mixing devices.
The physical parameters of the cartridge and the DECA system are the same. The mixes
have identical consistencies, setting kinetics and mechanical properties of the set product.
Therefore, when discussing the physical data of the Monophase and the Heavy Body, there
is no differentiation between the cartridge and the DECA version.
8
4 Chemistry of Polyethers, A-Silicones and Aquasil
4.1 Polyether
N
CO2
O
O
O
x
CO2
y
n
N
x=0,1; y=0,1
4.1.1 Main Features
• linear chain built up by tetrahydrofurane/ethyleneoxide polyethers
• the chain itself has hydrophilic properties which can be adjusted by the
tetrahydrofurane/-ethylenoxide ratio.
• reactive groups: aziridine moieties at the end of a linear polyether chain
• crosslinking reaction: ring opening of the aziridine-rings
• catalyst: strong acids (Lewis acids)
4.1.2 Main Problems
• a too high hydrophilicity leads to swelling during a long contact to water
• the strong acids may cause irritation of the skin and soft tissue
• strong intramolecular forces lead to a very hard polymer which is difficult to remove from
the patient’s mouth
• bad taste and odour
9
4.2 Traditional Addition Curing Silicones (A-Silicones)
Me
O
O
Si
Me
Si
Me
Si
Me
H
Me
O
x
Me
Si
Me y
Me
Me
n
x=0,1; y=0,1
SiH-crosslinkers (Me = Methyl group), x, y either 0 or 1
Me Me
Si
Me Me
O
Si
Me Me
O
Si
n
Vinylpolysiloxane chains (VPS)
4.2.1 Main Features
• the chain itself is hydrophobic
• reactive groups: vinyl groups at the end of the siloxane chain and SiH-groups in the
crosslinker
• crosslinking reaction: addition of SiH to the vinyl moieties
• catalyst: Pt-complexes
10
4.2.2 Problem:
Hydrophilicity can be achieved only by the addition of surfactants:
O
O
O
O
O
O
O
O
O
O
tail
head
The surfactant improves the wettability of the impression material. It is characterised by a
lipophilic head and a hydrophilic tail. Both characteristics are specified by the hydrophilic/lipophilic balance (HLB-value). In traditional A-Silicones the wettability of polyethers could
not be realised.
4.3 Aquasil
Me
O
O
Si
Me
Si
Me
H
Me
Me
O
Si
x
Me
Si
Me
y
Me
Me
n
x=0,1; y=0,1
SiH
Me Me
Si
Me Me
O
Si
Me Me
O
n
VPS
Me
Me
Si
Me
Me
Me
Me
Si
Si
O
Si
O
Si
O
Me
Me
Si
O
QM-resin
11
4.3.1 Main Features
• the chain in the VPS itself is hydrophobic
• branched ”QM resins” with a high functionality (quadrafunctional modified resins)
• reactive groups: vinyl groups at the end of the siloxane chain and SiH-groups in the
crosslinker
• crosslinking reaction: addition of SiH to the vinyl moieties
• catalyst: Pt-complexes
• hydrophilicity can be achieved by the addition of surfactants:
O
O
O
O
O
O
O
4.3.2 Main Differences to traditional A-Silicones
• HLB-value of the surfactant leading to better wettability, comparable to polyether
(achieved by a higher mobility of the surfactant).
• high functionality of the QM resin monomers leading to enhanced tear strength in
comparison to traditional A-Silicones.
The following figures show the build-up of the network of a traditional A-Silicone (see
Figure 1) and the new Aquasil impression material (see Figure 2).
In the case of Aquasil a much higher network density is built during the crosslinking reaction.
Figure 1:
Three steps of the polymerisation of a traditional A-Silicone
12
Figure 2:
Three steps of the polymerisation of QM-Resins
Legend for Figure 1 and Figure 2
Vinyl Poly Siloxane
SiH Crosslinker
QM-Resin
13
5 Physical Aspects
5.1 Development of Hydrophilicity
The hydrophilicity of impression materials is very important for the wettability of the material
under clinical conditions. In the case of traditional A-Silicones, the hydrophilic properties
could only be achieved by adding surfactants. These surfactants lead to the development of
hydrophilic properties during the setting reaction, but the development is too slow to reach
the good wetting properties of polyethers.
In the case of Aquasil a more effective surfactant is used. With this new surfactant the development of hydrophilicity is much faster, and the wettability of a polyether is reached before
the materials starts setting.
The change of hydrophilic properties can be measured by the change of the contact angle to
water. Figure 3 below shows the development of the contact angle of Aquasil Low Viscosity
and Aquasil Ultralow Viscosity in comparison to two traditional A-Silicones.
Figure 3:
Development of the contact angle of light bodies
14
The surfactants which are used in traditional A-Silicones and in Aquasil are both
characterised by a lipophilic head and a hydrophilic tail. This hybrid character between water
and lipid enables a surfactant to improve the mixability of water and lipids. The physical
parameter to measure the ability to improve this mixability is the so-called hydrophilic
lipophilic balance (HLB-value).
The main difference between the surfactant used in traditional A-silicones and the new
surfactant used in Aquasil is the chain length of the hydrophilic tail (n). The shorter tail in the
new surfactant enhances its mobility and leads to a higher HLB-value.
O
O
head
n
CH3
tail
5.2 Enhanced Shore A Hardness
Figure 4:
Shore A hardness and strain in compression
15
Aquasil Heavy FS in its two versions (1:1, cartridges and 4,55:1, for automatic mixers) has
been developed as a tray material for both the double mix and the putty / wash technique.
Especially the latter has been a domain of traditional hand mixed putties because the shore
A hardness of the existing Heavy Bodies was usually too low. Therefore these materials
were difficult to cut and their use was reduced to the double mix technique. As shown in
Figure 4, Aquasil Heavy FS has an extraordinary high shore A hardness of approximately 70.
It therefore can be used in the putty / wash technique as a replacement for a hand mixed
putty. Nevertheless the strain in compression of the set Heavy Body is higher than 2.0 %,
which prevents any problems during removal from the mouth and later on from the gypsum
model.
There is no difference in the physical properties (strain in compression, shore A hardness
etc.) between the two versions of Aquasil Heavy FS.
5.3 Enhanced Tear Strength
The tear strength of an elastomeric impression material is a very important parameter
because the material has to withstand tear forces especially when the impression is removed
from the mouth. Three parameters are important for the behaviour of an elastomeric material
under the influence of tear forces. The tear strength R0 expresses the quotient of the force at
break versus the area on the break surface. When tear force is applied to the specimen it is
usually deformed. This deformation is leading to a change of the area at the break surface. In
the case of the corrected tear strength R1, this deformation is taken into account. The Emodulus is an theoretical approximation to an infinitesimal small deformation.
One of the most important improvements of the Aquasil System, which never before could be
achieved by any existing impression material, is its extraordinary high tear strength. The set
impression materials are made of an elastic crosslinked polymer network and a more or less
high content of structure stabilising fillers. In the case of traditional A-Silicones, the
mechanical stability was reached mainly by a high filler content. These fillers were responsible for a strongly stress depending viscosity (non-Newtonian flow behaviour). Low viscosity
could only be reached by a low filler content and had the disadvantage of a low tear strength.
Because of the higher functionality of the new quadrafunctional modified resins (QM-resins)
in the Aquasil system, the crosslinking density of the network is much higher as is the case in
traditional A-Silicones. Even the very low viscous Aquasil ULV with a filler content of some
16
10 % has a higher corrected tear strength R1 than the competitive products in the test (see
Figure 5).
Figure 5
Light Body impression materials
In the case of the highly filled Aquasil Monophase FS and Aquasil Heavy FS, a tear strength
is reached which never before could be achieved by any existing impression material.
17
Figure 6
Monophase impression materials
Figure 7
Heavy Body impression materials
18
5.4 Rheological Aspects of the Aquasil Products
5.4.1 Introduction
The most important features with regard to the flow characteristics are the rheology of the
unset single pastes and the time dependent change of the rheological parameters during
setting reaction. In the following, some theoretical aspects will be discussed for a better
understanding of the flow characteristics of the different Aquasil products,.
Newtonian Fluid:
Non-Newtonian Fluid:
The viscosity is independent on the shear
The viscosity is highly dependent on the shear
stress.
stress.
ƒ
yield stress
ƒ
thixotropy
ƒ
structure viscosity
Examples:
Examples:
ƒ
water
ƒ
polymer solutions
ƒ
solvents
ƒ
emulsions
ƒ
silicone oils
ƒ
soles
ƒ
paraffin oils
ƒ
highly filled suspensions (pastes)
All existing impression materials including the Aquasil products are two-phase systems
comprising a viscous matrix and a high dispersed solid filler. The rheological properties of
such a paste are always characterised by a non-Newtonian flow behaviour with the
parameters shown above.
19
The non-Newtonian flow characteristics are the result of a rheological substructure, which in
the case of a highly filled suspension is built up by the liquid matrix and the small filler particles. In addition the surfactant, which is usually insoluble in the silicone matrix, is building
an oil/oil dispersion. This complicated three-phase structure is destroyed when stress is
applied to the system, therefore these pastes show high viscosities when left undisturbed
while viscosity is dramatically reduced during stress, as is the case during impression taking.
The lower the viscosity during application, the better the material can flow into the details of
the preparation. On the other side a very thin material will always tend to drop from the teeth.
In addition, in a very thin matrix the filler which is necessary to reinforce the network tends to
separate under the influence of gravity.
Therefore it is very important that the rheological substructure of an impression material is
rebuilt quickly. The time-dependent relaxation of viscoelasticity is called thixotropy.
loss modulus G"
shear modulus G*
δ
loss angle
storage modulus G'
Figure 8:
Rheological parameters
The viscoelasticity of a non-Newtonian fluid has to be described by the shear modulus
G*=G’+G”. This complex rheological parameter is calculated as the sum of the viscous
properties of a liquid (loss modulus G”=2πνη’ ) and the elastic properties of a solid (storage
modulus G’). In cases where the loss modulus is higher than the storage modulus, the
system behaves more like a liquid, otherwise it behaves like a solid. G*, G’ and G” are
vectors which can be described in the vectorian diagram shown in Figure 8.
20
The rate of solid elasticity (G’) and liquid viscosity (η’) is expressed by the loss angle
δ=arctan (G”/G’). In cases where the loss angle is higher than 45°, the system behaves
more like a liquid, otherwise the solid properties are dominant.
The adjustment rheological behaviour of an impression material has always been a result of
compromises which did not always satisfy the dentist’s needs.
5.4.2 Experimental Data
5.4.2.1 Light Bodies
In the case of a Light Body the material should easily flow into any detail even under nonstress conditions, which means even under the influence of gravity. In practise such
materials always tend to drop from the teeth. In the case of Aquasil ULV this problem could
be solved by a highly stress depending viscosity in combination with an optimised thixotropic
behaviour. During the application with the static mixing devices stress is applied to the Light
Body, which is leading to a disturbed rheological substructure. Immediately after release out
of the cartridge the flow behaviour of Aquasil ULV is characterised by a very low viscosity
and a loss angle above 60°. Because of this behaviour the material can easily flow into every
detail even under the low stress conditions of gravity. Figure 9 below shows the viscosity
(measured with an oscillation/rotation rheometer) of Aquasil ULV immediately after release in
comparison to competitive Light Body materials.
21
Figure 9
Viscosity of mix
Because of the thixotropy within the first 10 or 15 seconds, the rheological substructure of
Aquasil ULV is rebuilt, leading to a high viscosity in combination with a loss angle below 40°:
The material now does not flow from the surface of the teeth and has no tendency to drop. It
is important that the rising up of the viscosity is mainly not a result of the setting reaction but
of the rebuilt of the rheological substructure. Therefore it is a reversible process, which is not
combined with a reduced working time of the material. At a temperature of 23°C even after
150 seconds, the loss angle can again rise to high values of > 45° if stress is applied to the
material, as would be the case, when a dental impression is taken. As a result of the
accelerated setting reaction at 35°C, this time is reduced to 75 seconds.
The rebuilt of the rheological substructure of Aquasil ULV can be shown by a measuring the
time depending viscosity of the single pastes after applying stress. The experimental results
are shown in Figure 10.
22
Figure 10
Thixotropy of Aquasil ULV
5.4.2.2 Heavy Body
In the case of a Heavy Body it is very important that the material has sufficient body
otherwise the material would flow out of the tray into the patient’s oropharnyx. The practical
parameter of bodiness again has to be described by the shear modulus G*. To prevent the
flow of the Heavy Body from the tray, the solid properties (G’) mainly dominate the
rheological character of these materials. But there is always a certain stress (so-called yield
stress), which has to be overcome to change the solid to a viscous behaviour. Else it would
be impossible to release the material out of the cartridge. In contrast to a Light Body the
viscosity of a Heavy Body has to be sufficiently high even after the overcome of the yield
stress. Otherwise the Heavy Body would not be able to disturb the rheological structure of
the Light Body and the latter would not flow into the details of the preparation during taking
the impression. On the other side too high viscosities were always leading to very high
extrusion forces. The rheological behaviour of Aquasil Heavy Body FS shoes sufficient
rigidity, which prevents any flow of the material out of the tray but low extrusion forces during
application. Nevertheless the viscosity of Aquasil Heavy Body FS is always high enough to
disturb the rheological substructure of Aquasil ULV or LV. Again there is no difference in the
rheological properties of the mixed Heavy Body between the two versions of Aquasil Heavy
Body FS (1:1, cartridge and 4,55:1 for automatic mixers).
23
5.4.3 Setting reaction
During the setting reaction of A-silicones, the viscoelasticity of the impression material
changes from a more liquid paste which is able to flow into the details of the preparation, to
an elastic solid which completely recovers after deformation. This change of rheological
properties is shown by the development of the loss angle during the setting reaction.
The figures below show the rheological behaviour of the impression materials after releasing
through the mixing tip.
Figure 11 and 12:
Setting reactions of competitive products
The product in Figure 11 (Provil Light) has a loss angle higher than 45° at the beginning.
Therefore it easily flows into the details of the preparation. The angle passes the 45° line
after more than 100 seconds. Therefore the material tends to drop from a surface under the
influence of gravity. Under clinical conditions this material may drop from the teeth.
At the beginning of the setting reaction the loss angle of the product in figure 12 (Blend-agum Light) is below 45°. This product has no tendency to drop, but on the other side it will
not flow into the details under the low stress conditions during application.
24
In the case of Aquasil Ultralow Viscosity (Figure 13) the loss angle at the beginning of the
setting reaction is higher than 45°. That means when the material is applied to the preparation it will flow into the details even under very low stress conditions. However, after a few
seconds the 45° line is passed, and the solid character of the material becomes dominant.
Therefore the material will not drop from the teeth.
Setting Reaction
Aquasil Ultralow Viscosity
loss angle delta/°
90
45
0
0
Figure 13:
50
100
150 200
time/s
250
300
350
Setting reaction of Aquasil Ultralow Viscosity
In Conclusion:
Conventional Light Body impression materials are either unable to flow into the details of the
preparation or they tend to drop.
Due to its unique rheology Aquasil ULV combines both good flow behaviour with nondropping behaviour.
25
6 Handling Aspects of the new Cartridge System
6.1 Light Bodies
The new cartridge system for the Light Bodies comprises a smaller extrusion gun and a
smaller double-chambered cartridge. The extrusion force F =σπR2 of an impression is
determined by stress σ and the radius R of the cartridge. Therefore the reduced diameter of
the two chambers makes it easier to release the material out of the cartridge.
The stress σ=τb+ηdγ/dt which is necessary to release a certain impression material is
characterised by the yield stress τb, the viscosity η of the material and the shear rate dγ/dt
during application. The yield stress and the viscosity are material constants, while the shear
rate is determined by the characteristics of the application itself. In the case of a Light Body,
only low amounts of material are extruded per time (usually less than 4 ml during 20 – 30
sec). Therefore the shear rate is low. In addition the viscosity is usually low. As a result the
extrusion force is mainly determined by the yield stress. The table below shows the initial
force which has to be applied to overcome the yield stress of Aquasil Ultralow Viscosity and
Aquasil Low Viscosity in comparison to Reprosil HF Light in the old 48 ml cartridge and the
new 25 ml cartridge.
yield stress σ
diameter of cartridge
48 ml cartridge/
25 ml cartridge/
25 ml cartridge/
Reprosil HF Light
Aquasil LV
Aquasil ULV
10 Pa
10 Pa
2.5 Pa
2 x 1.8 cm
2 x 1.5 cm
2 x 1.5 cm
2 x 25.4 N
2 x 17.8 N
2 x 4.42 N
0%
70 .1 %
82. 6 %
chamber
extrusion force
( )
2
F = d2 •π•σ
reduction of extrusion
force (in %)
26
6.2 Heavy Body and Monophase
The new cartridge system for the Heavy Body and the Monophase comprises the larger
AutoMix 75 gun and a double chambered cartridge with a larger volume but nearly identical
radius of the chambers. The volume of 75 ml per cartridge in most cases contains sufficient
material for two full arch impressions. In the case of the old 48 ml cartridge usually only one
impression could be taken per cartridge. With each impression, up to 10 ml of each cartridge
have been wasted.
In contrast to the application of a Light Body usually up to 30 or 40 ml of Heavy Body can be
released out of the cartridge in less than 30 seconds (according to in house evaluations by
dental assistants). Therefore the shear rate of the application of a Heavy Body is high. In
addition the viscosity of a Heavy Body is usually also high. The theoretical extrusion force for
a Heavy Body depends on the yield stress but also on the viscosity of the material. In order
to reduce the extrusion force the yield stress and the viscosity of the two consistencies have
been optimised. Since there is always some additional friction inside the extrusion gun and
the cartridge, the practical extrusion force is always higher than the theoretical value caused
by viscosity and yield stress. Therefore in practise the geometric and ergonomic design of
the gun and the cartridge also has some influence on the extrusion force. Since the radius
has nearly been unchanged, the geometrical influence can be neglected. On the other side
the ergonomic improvements of the new gun lead to a reduction of 20 – 30 % of the practical
extrusion force.
27
7 Material Scientific Investigations
(University of Basel, Institute of Material Science, Technology and Propaedeutics, Prof. Dr. Wirtz)
The two Light Body materials (Aquasil Ultralow Viscosity and Aquasil Low Viscosity) were
investigated at the University of Basel.
In the so-called shark fin test the flow characteristics of different impression materials under
pressure are tested. The material is loaded with a weight of 275 g and has to flow into a split
which has the shape of a shark fin. After setting the height of the resulting specimen is
measured. Good flow characteristics are shown in a high specimen. In the figure below the
results of the test are shown.
Figure 14:
Shark Fin Test
In comparison to the other materials tested, the Aquasil materials show a very good flow
behaviour.
In addition to the extraordinary good flow characteristics both Aquasil materials were tested
regarding dimensional change, recovery from deformation (torsion tests), and reproduction of
detail. Both materials show excellent reproduction of detail (10 µm) and a very low
dimensional change (0.01 % for Aquasil ULV and 0.012 % for Aquasil LV, measurement
started 10 minutes after start of mix). The recovery from deformation (torsion of 45°) was
98.7 % for Aquasil LV and 98.80 for Aquasil ULV.
28
8 Clinical Evaluation of Aquasil Impression Materials
The range of Aquasil impression materials have been clinically evaluated at different testing
sites. The material was tested with the former AutoMix II dispensing system in some cases
leading to a proposal for improvement. In the meanwhile, the new dispensing system
AutoMix 25 is available for Aquasil LV and ULV (see also chapter 6).
8.1 Clinical Evaluation of Aquasil Monophase in daily Practice
Main Investigators: Dr. John Farah and Dr. John Powers, The Dental Advisor PLUS
Objective and Duration
The main objective of this in vivo study was to determine the clinical performance of Aquasil
Quadrafunctional Hydrophilic Impression Material by dentists using polyether materials. The
duration of the study was six months.
Site of Investigation
This study took place in the operatories of 25 of Dr. Farah and Dr. Powers’ 250 clinical
consultants.
Investigation Methods
Each evaluator took a minimum of 20 impressions with Aquasil Monophase and rated the
material.
Results
Aquasil mixes to a smooth consistency for syringe and tray loading. Working time is
adequate, and the material reaches a final set in 6 minutes. Removal of the impression from
the mouth is easily accomplished. The material adapts well to moist teeth, and exhibits good
reproduction of detail, making margins easily readable. None of the consultants reported any
tears in thin sections upon removal from the mouth. Patients commented favourably on the
lack of a bad taste. Fit of restorations fabricated from Aquasil impressions was judged to be
good.
Conclusion
Aquasil received an 85% approval rating as an alternative impression material for clinicians
who like the handling characteristics of polyether.
29
8.2 Clinical Rating of Aquasil Monophase and Aquasil LV
REALITY1
Consistency and Handling
Aquasil Monophase has been introduced first in a hand mixed version. This hand mixed
version is judged to be mixed easier than polyether materials. Flow characteristics of Aquasil
LV were rated good. In comparison to polyether, Aquasil LV flows less, but is not as runny,
which is an advantage when impressing maxillary posterior teeth.
Clinical Use
Due to its hydrophilic nature, Aquasil works better on damp rather than dry teeth. There is
also no advantage and, indeed, it is contraindicated to blow the LV into the sulcus and over
the preparation. Eliminating the need to blow air definitely simplifies the technique and helps
to provide very consistent results.
Conclusion
Aquasil is formulated to give you all the advantages of both polyethers and polysiloxanes
while minimising the disadvantages. For the most part, it achieves that goal. On the polyether
side, Aquasil has similar wetting properties but not the bad taste or smell. It definitely has
more detail than other polysiloxanes when there is moisture in the area of the preparation.
Summary by DENTSPLY DeTrey GmbH
8.3 Clinical Evaluation of K-0084 (Aquasil) Putty2 and ULV3 in the Double Mix
Technique
Main Investigator: Prof. Dr. E. Beetke, University of Rostock
8.3.1 Controlled clinical study
Objective and Design
The purpose of this trial was the clinical evaluation of the combination of K-0084 Putty with
K-0084 ULV for the double mix technique. Randomly assigned, 35 impressions were either
1
Reality is an information source on aesthetic dentistry which was created by practising dentists for practising
dentists in the USA. ‘The Ratings’ are based on two main criteria: (1) results of valid and reliable research and (2)
actual clinical use by the Editorial Team.
2
Prototype material of Aquasil Soft Putty
3
Prototype material of Aquasil ULV
30
taken first with the test material or with the control material, followed by an impression with
the remaining material to manufacture a total of 55 inlays and onlays.
The materials were used according to the directions of use leaving the preparation moist for
impressions with K-0084 but blowing it dry for the control.
All impressions were first evaluated by the dentist and afterwards by the technician using a
scale from 1 (very good) up to 6 (unusable). The better rated impressions were poured twice
for the manufacture of the restoration. Finally, the first fit of the restoration on the tooth was
evaluated by the dentist.
Results
The impressions made from K-0084 were evaluated with an average rating from 1.9 to 2.1
for tear strength, detail reproduction, surface homogeneity, repeating rate and first fit. The
models made on base of these impressions were evaluated with an average rating of 2.0 for
pouring, model surface, detail reproduction and defects. There were no statistically
significant difference to the control found for these parameters.
Conclusion
The tested material combination can be recommended for the double mix technique. The
translucency of the light bodied material was modified as recommended by the investigator.
Summary by DENTSPLY DeTrey GmbH
31
8.3.2 Re-evaluation of Aquasil Soft Putty and Aquasil ULV for the double mix
technique
After modification of the colour and translucency of the Light Body and after being available
in the new cartridge system, both materials were re-evaluated.
Impressions in the double mix technique for 21 restorations were made and a favourable
handling of new AutoMix III4 and cartridges, very good colour combination, and high contrast
were reported. The tear strength, thixotropic behaviour (no tendency to drop), and detail
reproduction were lined out as impressive features of the evaluated materials.
8.4 Clinical Evaluation of K-0084 (Aquasil) Putty and ULV for the Putty / Wash
Technique
Main Investigator: Prof. Dr. E. Beetke, University of Rostock
Objective and Design of this pilot study
The purpose of this trial was a first clinical evaluation of the combination of K-0084 Putty with
K-0084 ULV for the putty / wash technique.
Randomly assigned, 15 impressions were either taken first with the test material or with the
control material, followed by an impression with the remaining material to manufacture a total
of 24 inlays and onlays.
The dentist rated the impressions clinically and choose the impression to be used for the
manufacture of the restorations.
After pouring both impressions, the technician rated the dies and decided which impression
had given the better result.
As a last step, the time to adjust the fit of the restoration was recorded.
Results and Conclusion
This clinical pilot study showed that the tested material is suitable and can be recommended
for the putty / wash technique. This is supported by clinically good rated criteria as the
handling, the reproduction of details, the readability, the shear strength, homogenous
surface, and the marginal quality of the manufactured restorations. Summary by DENTSPLY
DeTrey GmbH
4
Now available as AutoMix 25
32
9 Directions for Use
9.1 Description and technical Data
Precision Impression Materials based on quadrafunctional hydrophilic siloxanes
Aquasil Impression Materials are suitable for all precision impression techniques where
excellent hydrophilic properties, dimensional accuracy, high tear strength, and resistance to
permanent deformation are needed.
Aquasil Monophase FS and Aquasil Heavy FS are available in 75ml cartridges for the
AutoMix 75 dispenser developed to offer the best balance between economical and ease of
use and in DECA foil packs for dynamic mixing.
For an improved handling Aquasil LV and ULV are offered in 25ml cartridges for dispensing
in the smaller AutoMix 25 dispenser.
The Smart Wetting™ technology improves both wetting on the tooth surface and model
detail reproduction.
Aquasil Impression Materials comply with the requirements of ISO 4823 for dental
elastomeric impression materials.
9.1.1 Indication for Use
Aquasil Monophase FS is specially formulated to give the optimum viscosity at each stage
of the impression-taking procedure. It is delivered as a free-flowing syringe material that is
also a non-slumping, thixotropic tray material. Therefore, it is the ideal material for the
single-phase technique within the Aquasil system. Besides for a variety of crown and bridge
and partial or complete edentulous impression techniques, it is indicated for border moulding.
Aquasil Low Viscosity (LV) and Aquasil Ultra Low Viscosity (ULV) are low and ultra low
viscosity type impression materials for use as syringe materials. They can be used as
impression materials for denture relines and are compatible with Aquasil Heavy FS and
Aquasil Soft Putty for use in all dual phase techniques.
Aquasil Heavy FS combines the ease of use of the cartridge application or the dynamic
mixing with a machine with a putty-like hardness and is indicated as tray material for all dual
phase techniques.
33
Aquasil Soft Putty is a very high viscosity type impression material with optimum flexibility
for easy removal from undercuts and is used as tray material for the double mix technique or
as primary impression material for the putty/wash technique.
Aquasil Monophase FS, LV, and ULV may also be used for precise model duplication.
9.1.2 Contraindications
Do not use as a temporary reliner.
Do not use in combination with a polyether, condensation cured silicone, or polysulfide
material.
9.1.3 Precautions and Warnings
1. Silfix contains toluene and is highly flammable. Harmful by inhalation. Avoid contact with
eyes. Do not empty into drains. Use only in well ventilated areas. Take precautionary
measures against static discharge. Keep away of sources of ignition - no smoking.
2. Use normal surgery techniques to prevent inhalation and ingestion of low viscosity
impression materials.
3. Remove unset Aquasil Impression Material from clothing with a suitable cleaning solvent.
9.1.4 Interactions with Other Materials
1. Astringents based on aluminium salts may interfere with the setting reaction of vinyl
polysiloxanes. Please consult instructions for use of astringent to be used.
2. Aquasil Impression Materials should not be mixed with, or used in conjunction with
polyether materials, condensation cured silicones or polysulfide.
3. ‘Sulphur-containing’ polymeric gloves may interfere with the setting reaction of Aquasil
Impression Materials.
- Do not wear such gloves when kneading Aquasil Soft Putty.
- Do not touch retraction cords. Handle cords with college pliers.
- Do not touch prepared tooth.
34
9.1.5 Preparations
Tray
Silfix Adhesive should be used in all techniques with all types of
impression trays. Brush a thin layer of Silfix onto tray and allow to dry for 3
minutes.
Cartridges
Loading
1. Open the retainer of the dispenser. The cartridge can only be placed
into the dispenser with the notch at the reinforced flange of the
cartridge in a downward position (label upward). The cartridge flange
will fit directly behind the retainers on the dispenser.
2. If complete closing of the retainer is not possible or the plunger does
not enter into the cartridge, check to see that the cartridge is properly
aligned and the notch of the cartridge fits into the dispenser.
NOTE: The 25 ml cartridges are to be used with the AutoMix 25 only. The
75 ml cartridges in the AutoMix 75.
Assembling
1. For the first use of a cartridge remove and discard cartridge cap by
rotating ¼ turn anti-clockwise. Check to be sure the cap liner is
removed.
For subsequent usage, remove the used mixing tip.
2. Before attaching mixing tip, extrude ≈1cm of base and catalyst
(”bleeding” the cartridge) by squeezing dispenser trigger. Wipe end of
cartridge.
3. For direct intraoral application with Aquasil Monophase FS, Aquasil
Low Viscosity, or Aquasil Ultra Low Viscosity insert the intraoral tip into
the end of the mixing tip (stator).
Install the mixing tip on the cartridge. Lock the flange with a ¼ turn
clockwise.
NOTE: Make sure that the mix tip (stator) is securely attached at the
cartridge. For easier access to the preparation only rotate the
intraoral tip.
Leave the used mixing tip in place until the next use. The used
mixing tip serves as a self-sealing device.
35
DECA foil pack Filling the delivery cylinder
Insert the DECA foil packs into the respective chambers of the DECA
delivery cylinder (Figure 15-1). Line up the notch of the foil pack cap for
correct position on the delivery cylinder (Figure 15-2).
Activation
Firmly press the cap of each new foil pack onto the delivery cylinder to
activate. (Figure 15-3)
First Usage
Before attaching the dynamic mixing tip to a new foil package extrude at
least 1cm of base and catalyst paste (bleeding) using your dynamic
mixing device to ensure that both pastes are evenly dispensed.
Step 1
Figure 15:
Step 2
Step 3
Activation of foil packs
9.1.6 Disinfection
The impression can be disinfected with a standard disinfecting solution or spray.
9.1.7 Tray Cleaning Instruction
Use standard methods to clean the tray after removal of the impression material. Fix Solvent
may be used to help removing any remaining layer of Silfix.
36
9.1.8 Dispenser Cleaning Instruction
The dispenser may be cleaned with commercially available detergents. Do not use an
organic solvent that may tend to dissolve the plastic dispenser and plunger.
The dispenser may also be disinfected in an approved commercially available solution.
9.1.9 Casting and Electroplating
To avoid surface porosity of models, delay pouring with plaster for 15 minutes. The
impression may be poured up to fourteen days later.
The material is compatible with a range of die materials including epoxy materials and may
be silver or copper plated. Wait 60 minutes before start of plating or pouring with epoxy.
9.1.10 Technical Data
Aquasil
Aquasil LV
Aquasil
Aquasil
Aquasil
ULV
Heavy FS
Soft Putty
Type 1:
Type 0:
high
very high
consistency
consistency
consistency-
medium
- Heavy
putty
bodied
bodied
Monophase
FS
Classification ISO
Type 2:
4823:1992
medium
Total working time
Type 3: low consistency
light bodied
-
-
-
-
1:30
Setting time5
5:00
5:00
5:00
4:30
4:30
Linear dimensional
0.3%
0.3%
0.1%
0.05
0.05%
3.5%
4.5 %
6.5%
3.0 %
3.5%
99.6%
99.6%
99.8%
> 99.0 %
99.5%
0.40%
0.40%
0.25%
< 1.0 %
0.50%
<10µm
<10µm
<10µm
< 20 µm
<50µm
(ISO)
change (ISO)
Maximum strain in
compression (ISO)
Recovery from
deformation (ISO)
% Permanent
deformation (ADA)
Detail reproduction
5
Total time for application and minimum time in mouth.
37
9.1.11 Storage
Store Aquasil Impression Material between 18 - 25°C.
Do not store impression in direct sunlight.
9.1.12 Batch Number and Expiry Date
Do not use after expiry date.
The batch number should be quoted in all correspondence, which requires identification of
the product.
If you have any questions, please contact:
DENTSPLY DeTrey GmbH (Manufacturer), De Trey-Straße 1, D-78467 Konstanz,
Phone (0 75 31) 5 83-0
DENTSPLY United Kingdom, Hamm Moor Lane, Addlestone, Weybridge,
Surrey KT15 2SE, England, Phone 01932-853422
© DENTSPLY DeTrey 99-09-22
38
9.2 Step-by-Step Instructions
9.2.1 Single Phase Technique
Aquasil Monophase FS
Aquasil Monophase FS is available in 75 ml cartridges for the AutoMix 75 dispenser and in
DECA foil packs for dynamic mixing.
Besides common steps for the Single Phase Technique take account of the special
recommendations for the handling of Aquasil Impression Materials listed below.
APPLICATION
Total Time for Application6
Minimum Time in Mouth (ISO)
Aquasil Monophase FS
2:00
3:00
Minimum Time in Mouth of Single Phase Impression
3:00
Mixing
Fill the prepared tray directly with the AutoMix75 or with a dynamic mixing device using the
DECA foil packs.
Preparation for intra-oral application
Directly backfill a syringe for use with light bodies with the AutoMix75 or a dynamic mixing
device or attach an intraoral tip onto the 75ml cartridge
When using the 75ml cartridge system two simultaneously used cartridges and dispensers
(one for intraoral application and one for filling the tray) may facilitate the chairside protocol.
6
Describes the time from the start of mix till the impression has to be seated and corresponds to the Total Work
Time (ISO) for hand mixed materials and to the Minimum Work Time (including mixing time) (ADA) for cartridge
materials.
39
Impression Technique
1. Clean Impression area with air/water spray and remove excess water.
2. Mix and place Aquasil Monophase FS in prepared tray as described above.
3. Inject with the syringe or directly from the cartridge onto and around tooth preparations. It
is suggested to syringe completely around preparation at the gingival margins twice,
maintaining the syringe tip in the impression material. Aquasil’s hydrophilic properties
improve adaptation to the tooth enabling better ‘wetting’.
4. Seat tray within 2 minutes after having started to mix the material.
5. Aquasil Impression Materials set faster in the mouth than on the bench. Retain impression
in position for at least 3 minutes. Prior to removal, make sure the impression is firm,
resilient, and non-tacky.
6. Rinse impression under cold water and blow dry.
7. Do not store impression in direct sunlight.
9.2.2 Double Mix Technique
Aquasil Heavy FS or Aquasil Soft Putty with Aquasil LV or Aquasil ULV
Besides common steps for the Double Mix Technique take account of the special
recommendations for the handling of Aquasil Impression Materials listed below.
Aquasil Heavy FS is available in 75ml cartridges for the AutoMix75 or in DECA foil packs for
dynamic mixing.
APPLICATION
Aquasil Soft Putty
Aquasil Heavy FS
Mixing technique
knead with
fingertips until
colour is uniform
1:1
0:30
static or dynamic
mixing tips
Mixing Ratio
Mix Time
Total Time for
Application7
Minimum Time in
Mouth (ISO)
Aquasil ULV
extrusion through static mixing
tips
1:30
2:30
3:00
3:30
Minimum Time in Mouth of Double Mix Impression
7
Aquasil LV
3:30
Describes the time from the start of mix till the impression has to be seated and corresponds to the Total Work
Time (ISO) for hand mixed materials and to the Minimum Work Time (including mixing time) (ADA) for cartridge
materials.
40
Mixing and filling the tray
Aquasil Soft Putty
Take equal amounts of catalyst and base using the colour coded measuring spoons and
knead with fingertips until colour of mix is uniform. Immediately fill prepared tray.
NOTE: Do not interchange measuring spoons.
Aquasil Heavy FS
Dispense Aquasil Heavy FS either with the AutoMix 75 or a dynamic mixing device directly in
the prepared tray.
Impression Taking
1. Clean Impression area with air/water spray and remove excess water.
2. Inject light body with cartridge system onto and around tooth preparations. Squeeze
dispenser trigger with moderate and even pressure to begin mixing material. Material will
stop flowing after trigger is released. It is suggested to syringe completely around
preparation at the gingival margins twice, maintaining the syringe tip in the impression
material. It is not necessary to blast with air for thinning out the material. Aquasil LV and
ULV Impression Material's hydrophilic properties improve adaptation to the tooth enabling
better ‘wetting’.
3. Seat tray within 1½ minutes after start of extrusion Aquasil Heavy FS onto the tray or
mixing Aquasil Soft Putty, respectively.
4. Aquasil Impression Materials set faster in the mouth than on the bench. Retain impression
in position for at least 3½ minutes. Prior to removal, make sure the impression is firm,
resilient, and non-tacky.
5. Rinse impression under cold water and blow dry.
6. Do not store impression in direct sunlight.
41
9.2.3 Putty / Wash Technique
Aquasil Soft Putty or Aquasil Heavy FS with Aquasil ULV or Aquasil LV
Due to the excellent flow characteristics it is recommended to choose Aquasil ULV as the
light body for the putty wash technique. Additionally, less material compared to traditional
light bodies is used in order to obtain optimal results.
Besides common steps for the Putty / Wash Technique take account of the special
recommendations for the handling of Aquasil Impression Materials listed below.
Aquasil Heavy FS is available in 75ml cartridges for the AutoMix75 or in DECA foil packs for
dynamic mixing.
APPLICATION
Mixing technique
Mixing ratio
Mix Time
Total Time for Application8
Minimum Time in Mouth (ISO)
Aquasil Soft
Aquasil Heavy
Putty
FS
static or
knead with
fingertips until dynamic mixing
tips
colour is
uniform
1:1
0:30
1:30
3:00
Minimum Time in Mouth of
Primary Impression
Aquasil
LV
Aquasil
ULV
extrusion through
mixing tips
2:30
3:30
3:00
Minimum Time in Mouth of Secondary Impression
3:30
Mixing and filling the tray
Aquasil Soft Putty
Take equal amounts of catalyst and base using the colour coded measuring spoons and
knead with fingertips until colour of mix is uniform. Immediately fill the prepared tray.
NOTE: Do not interchange measuring spoons.
Mixing Aquasil Heavy FS
Dispense Aquasil Heavy FS with the AutoMix 75 or a dynamic mixing device directly in the
prepared tray.
8
Describes the time from the start of mix till the impression has to be seated and corresponds to the Total Work
Time (ISO) for hand mixed materials and to the Minimum Work Time (including mixing time) (ADA) for cartridge
materials.
42
Impression Taking
1. Clean Impression area with air/water spray and remove excess water.
2. For the primary impression seat tray within 1½ minutes after start of mixing Aquasil Soft
Putty or after starting to dispense Aquasil Heavy FS into the tray. Retain impression in
position for a minimum of 3 minutes.
3. Remove, clean and prepare primary impression for the secondary impression.
4. Clean area to be duplicated with air water spray. Remove spray water.
5. Inject light body with cartridge system onto and around tooth preparations. Squeeze
dispenser trigger with moderate and even pressure to begin mixing material. Material will
stop flowing after trigger is released. It is suggested to syringe completely around
preparation at the gingival margins twice, maintaining the syringe tip in the impression
material. It is not necessary to blast with air for thinning out the material. Aquasil LV and
ULV Impression Material's hydrophilic properties improve adaptation to the tooth enabling
better ‘wetting’.
6. Syringe additional light body on remaining occlusal tooth surfaces and/or on prepared
primary impression.
7. Seat tray within 2½ minutes after start of injecting the light body.
8. Aquasil Impression Materials set faster in the mouth than on the bench. Retain impression
in position for at least 3½ minutes. Prior to removal, make sure the impression is firm,
resilient, and non-tacky.
9. Rinse impression under cold water and blow dry.
Do not store impression in direct sunlight.
43
10 Literature List
Selected Literature - November 1999
1.
Beetke E (1997). Clinical evaluation of K084 Putty and Ultra Low Viscosity for the putty
wash technique. Summary by DENTSPLY DeTrey.
2.
Beetke E (1997). Clinical evaluation of K084 Putty and K084 Ultra Low Viscosity in the
double mix technique. Summary by DENTSPLY DeTrey.
3.
Christensen WG, Amidan BG, Christensen RP (1996). Margin fit of new hydrophilic
addition reaction silicone impression material. J Dent Res 75:SI;2865. ¹
4.
Div (1996). Aquasil. The Dent Adv + 6:1;2.
5.
Div (1996). Impression material, new concept addition reaction silicone. CRA News
20:5;3. ¹
6.
Div (1996). Abdruckmaterial, neues Konzept additionsvernetzender Silikone. CRA
News (D) 4:3.
7.
Div (1996). Impression materials (new). Reality Now 83:1-2. ¹
8.
Div (1997). Aquasil / Aquasil LV. Reality 11:193/4,202/3.
9.
Hare RV (1997). Bonding between elastomeric impression materials. Effect on tear
strength. J Dent Res 76:SI;3288. ¹
10.
Latta MA, Barnes DM, Cavel WT, Blankenau RJ, Blitzer RM, Wuertz KM (1998).
Clinical evaluation of a hydrophilic impression material. J Dent Res 77:SIA;482.
11.
Vaughn V, Kugel G, Perry R, Noonan ST (1997). Measuring flow of elastomeric
impression materials using the Shark-Fin-Device. J Dent Res 76:SI;3292.
12.
Wirz J, Naef V, Schmidli F (1998). Moderne Elastomere in neuen Darreichungsformen
und Verarbeitungssystemen - Eine vergleichende Materialprüfung. Teil 1: Material und
Methoden. Quintessenz 49:4;403-409.
13.
Wirz J, Naef V, Schmidli F (1998). Moderne Elastomere in neuen Darreichungsformen
und Verarbeitungssystemen - Eine vergleichende Materialprüfung. Teil 2: Resultate
und Diskussion. Quintessenz 49:5;513-52
44