8. Elastic Impression Materials Flashcards by J L

Impression Technique
• Fabricate \_\_\_\_
• Apply tray adhesive
• Bleed \_\_\_\_
• Fill syringe
• Fill \_\_\_\_
• Syringe impression mat around teeth
• Insert \_\_\_\_

custom tray
dispenser
syringe
tray

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Application of Tray Adhesive
• Use right ____ for impression material
• Inadequate adhesion= ____ and ____

adhesive
dislodgement
distortion

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Adhesives in Impression Tray
• Adhesives improve ____ of impressions

material shrinking > ____ dye
if you use adhesive and material is shrinking and you use an adhesive and you end up with a slightly ____ dyed

accuracy
undersized
oversized

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Viscosity of Impression Materials
• \_\_\_\_
• Heavy Bodied
• \_\_\_\_/Regular Bodied 
• Light Bodied (Wash

light body = most ____ detail

putty
medium
accurate

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Impression techniques

(Multiple mix) Putty/Tray Wash

multiple ____ technique
the putty is used to form a ____

mix

custom tray

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Impression techniques
Putty wash continued

remove plastic sheet > squeeze in light body (also called a ____)

____ mix technique
- in other techniques heavy body is used, but it’s not used to ____ the tray

wash
double
load

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Impression techniques
Single mix

same ____ but we are squeezing around the teeth

viscosity

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Properties of an ideal impression material

Accuracy
• Reproduction of ____
• Dimensional ____

____
Tear Strength/Energy
Adherence to ____ tray
Compatibility with ____ materials

detail
stability
elasticity
impression
die

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Tear Strength
• Resistance to Tearing of Elastomers
1. ____ 2. ____ 3. ____

polysulfide
polyether
silicones

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Ideal Properties
Handling Characteristics
• Working time
• Setting time
• Shelf life

ideal working time = ____
setting time for experience is ____; up to ____ for inexperienced
normal shelf life is how long can we store material before it begins to ____

one
2-3
6
degrade

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Elastic Impression Materials Classification

• Elastomers
– Aqueous Elastomers
• ____
• ____

– Non Aqueous Elastomers/Rubber Based
• \_\_\_\_
• \_\_\_\_ 
• \_\_\_\_
• \_\_\_\_

agar agar
alginate

polysulfide
condensation silicone
addition silicone
polyethers

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Non Aqueous Elastomers (Rubber based Impression materials)
a. Presentation
\_\_\_\_ pastes 
\_\_\_\_ systems
b. Clinical use and features

base and catalyst

automix

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Polysulfide (mercaptan)

Base Paste
____ polymer with terminal and pendant -____- groups
Fillers ____
- ____ Plasticizers

Accelerator Paste
• Cross linking agent - ____
• Fillers - ____
• Plasticizers

polysulfide
SH
TiO2

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Setting Reaction
• Condensation polymerization with ____ by-product
• ____ Rn

polysulfide prepolymer is also called a ____. with the ____ (catalyst), it gives you a ____ and some lead oxide and water.

condensation produce is ____ which is released via a bubble

in condensation reaction > acid ____, diminishing the ____ of the impression

water
exothermic
mercaptan paste
lead dioxide
cross-linked polysulfide

water
evaporates
accuracy

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Presentation

____
Medium
____ body
Used with ____ tray

heavy
light
custom

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Dispensing of Impression

• Squeeze ____ lengths of base and catalyst onto mixing pad

equal

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Mixing

• Mix with stiff spatula to a ____ color

uniform

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Polysulfides- Properties
Accuracy
• Detail reproduction - 25 um
• Elastic recovery 96.5%
 • Flow  0.4-1.9%
• Flexibility 10-16%

ER is ____
____ flowing material, and it causes a ____ working and setting time
flexibility is ____

low
high
long
high

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Polysulfides- Properties
Accuracy

• Dimensional stability
– setting rn
– flow on setting
– no ____ pours

Shrinkage (24hr) 0.45%
Tear strength ____
Storage ____ hr
____ shrinkage due to condensation product > cannot make ____ pours; only first pour is accurate
high ____ > if it were low or it would break often
____ elasticity and flexibiilty > stretched beyond capability to recover so those characteristics
bc of the shrinkage > cannot store it for more than ____ hour, but newer research says ____

multiple
high
1

high
multiple
tear strength
high
one hour
30 minutes

Polysulfides- Properties
Handling
• Working time - \_\_\_\_ min
• Setting time - \_\_\_\_ min
• Effect of temp/humidity 
• \_\_\_\_ on Loading
• Can be \_\_\_\_

have a long ____ and ____
setting is ____ at hot temperatures and humidity
non aqeuous elastomers are highly ____ and bc of that they can all be electroplated

5-7
9-12
distortion
electroplated
working time
setting time
accelerated
hydrophobic

Polysulfides- Biological/Clinical Features

Smell/taste
____ working/setting time
____ flow (low viscosity) on mixing
____ flexibility/tear strength ____ accuracy

not pleasant smell and will ____ your clothes

long
high
high
low
stain

Condensation Silicone

Base paste
____

• Catalyst Paste/liquid
• Crosslinking agent:
____ +
• ____

the base paste is best described as a ____ bc it is already polymerized

hydroxy terminated polydimethryl siloxane

orthoalkyl silicate
tin octoate
prepolymer

Setting Reaction
____ polymerization with (volatile) ____
by-product

accuracy is similar to ____

condensation
alcohol
polysulfide

Presentation

• ____, Heavy, ____ and Light bodied

putty

medium

``` Condensation Silicones Properties Accuracy • Reproduction of detail 25 um Elastic recovery ____% Tear strength ____ ``` * Dimensional Stability – Shrinkage (24hr) 0.2-1% * Storage ____ hr - similar to polysulfide > the shrinkage is too ____ and the accuracy is not greate

99 high 1 high

Condensation Silicones- Handling Properties * Working time ____ min * Setting time ____ min * Effect of temp and humidity • Can be ____ - key negativity here = high ____ due to release of alcohol - but the other properties are better than ____

``` 3 6-8 electroplated shrinkage polysulfide ```

Condensation Silicones- Biological /Clinical characteristics ``` • Clean, ____ taste/smell • Control setting time with amount of ____ • ____, dry field • ____technique ```

pleasant accelerator hydrophobic putty/wash

Addition Silicone (PVS) Base Paste • ____ polymer • Silanol and fillers Catalyst Paste • ____ • ____ - PVS is the most ____ non-aqueous elastomer impression material - base paste polymer is very similar to what we saw for the ____

``` vinyl terminated polydimethyl siloxane chloroplatinic acid filler popular condensation silicone ```

Setting Reaction ____ polymerization reaction with no ____ by-products - the by-products do not affect the ____

addition volatile accuracy

``` Addition Silicones Accuracy • Reproduction of detail 25 um • Elastic recovery 99.9% • Tear strength ____ • Shrinkage (24hr) 0.01-0.2% • Storage ____ week ``` - ER is very ____

low to high 1 high

``` Addition Silicones Accuracy • Porosity - ____ gas • Distortion - Poor use of adhesive ``` - manufacturer recommends you wait about ____ after the impression has set before you pour it

hydrogen | 30 minutes

Addition Silicones ``` Handling • ____, Heavy, ____, Medium, light body • Working time - ____ min • Setting Time - ____ min – temperature, catalyst, contamination – tin/sulfur compounds, powdered gloves thinners ``` - rxn is affect by ____ and amount of ____ - tin/sulfure compounds will ____ or ____ the setting - - ____ gloves have sulfur! - thinners reduce the ____ even further

``` putty regular 2-4.5 3-7 temp catalyst slow down stop powdered viscosity ```

Addition Silicones- Clinical Characteristics * Pleasant taste/odor * Delay pouring for ____ hr (H2) releasing • ____ pours * ____/hydrophilic products * ____ inhibition * ____ - materials have been improved by addition of ____ to make them more hydrophilic > easier to spread on teeth - however, if electroplating, ____ materials are better

1 multiple ``` hydrophobic tin and sulfure electroplating surfactants hydrophobic ```

Effect of Storage on Accuracy • Top row - Addition silicone • Bottom row - Condensation silicone • A=30min, B=6hrs, C=24hrs - all ____ the same; but with ____ there is a gap that develops after 30 minutes

addition silicone | condensation silicone

Polyether - Composition Base Paste • ____ polymer • ____ - Filler • ____ - Plasticizer Catalyst Paste • ____ • Filler + Plasticizer this base paste is also a ____

polyether colloidal silica glycol ether alkyl aromatic sulfonate prepolymer

Polyether Reaction • ____ polymerization with ring opening of ____ (ethylene-imine). • No ____ by-products Polyether polymer + Sulfonic ester ---> ____ rubber - side chains = ____

``` ionic aziridine rings volatile polysulfide aziridine rings ```

Pentamix Delivery System | • ____ auto mix system

pentamix

``` Polyether Properties Accuracy • Reproduction of detail 25m • Elastic recovery 98.5% • Tear strength ____ • Shrinkage (24hr) 0.2- 0.3% • Storage ____ wk • ____ absorption ``` - ER is not as high as ____ - make sure no humidity or moisture when storing bc otherwise it will absorb ____ and ____ > poor ____

``` low to hight 1 water addition silicone water swell accuracy ```

``` Polyether Properties Handling • Light body, medium, heavy body • Working time - ____ min • Setting ____ min • ____ • Effect of thinners ``` - which impression is most rigid? > ____ - has thinners to reduce the ____

``` 2.5 3-5 rigid polyether viscosity ```

Polyether Properties Biologic Properties • ____ reaction to catalyst

dermal

Polyether Clinical Characteristics ``` • Pleasant handling but ____ taste • ____ impression material – Limit to few teeth, no severe ____ • ____ • ____ working time • ____ plate ``` - can be electroplated and for this ____ is the most common, rather than copper

``` bitter stiffest undercuts hydrophilic short silver silver ```

Disinfection Diseases of concern • Viral diseases eg. ____, AIDS, ____

hepatitis B | herpes simplex

Disinfectants ``` • 1% ____ • 2% ____ solution immersion for 10-30 min • ____ • ____ ``` - some of the products pick up ____

``` sodium hypochlorite glutaraldehyde iodophors phenolics moisture ```

Elastomers Aqueous vs. Non Aqueous Accuracy Elastic recovery Tear Strength

comparisons??

Check the table for the comparisons of non-aqueous elastomers!

yay