8. Elastic Impression Materials Flashcards
Impression Technique • Fabricate \_\_\_\_ • Apply tray adhesive • Bleed \_\_\_\_ • Fill syringe • Fill \_\_\_\_ • Syringe impression mat around teeth • Insert \_\_\_\_
custom tray
dispenser
syringe
tray
Application of Tray Adhesive
• Use right ____ for impression material
• Inadequate adhesion= ____ and ____
adhesive
dislodgement
distortion
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
Viscosity of Impression Materials • \_\_\_\_ • Heavy Bodied • \_\_\_\_/Regular Bodied • Light Bodied (Wash
light body = most ____ detail
putty
medium
accurate
Impression techniques
(Multiple mix) Putty/Tray Wash
- multiple ____ technique
- the putty is used to form a ____
mix
custom tray
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
Impression techniques
Single mix
- same ____ but we are squeezing around the teeth
viscosity
Properties of an ideal impression material
Accuracy
• Reproduction of ____
• Dimensional ____
- ____
- Tear Strength/Energy
- Adherence to ____ tray
- Compatibility with ____ materials
detail stability elasticity impression die
Tear Strength
• Resistance to Tearing of Elastomers
1. ____ 2. ____ 3. ____
polysulfide
polyether
silicones
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
Elastic Impression Materials Classification
• Elastomers
– Aqueous Elastomers
• ____
• ____
– Non Aqueous Elastomers/Rubber Based • \_\_\_\_ • \_\_\_\_ • \_\_\_\_ • \_\_\_\_
agar agar
alginate
polysulfide
condensation silicone
addition silicone
polyethers
Non Aqueous Elastomers (Rubber based Impression materials) a. Presentation \_\_\_\_ pastes \_\_\_\_ systems b. Clinical use and features
base and catalyst
automix
Polysulfide (mercaptan)
Base Paste
____ polymer with terminal and pendant -____- groups
Fillers ____
- ____ Plasticizers
Accelerator Paste
• Cross linking agent - ____
• Fillers - ____
• Plasticizers
polysulfide
SH
TiO2
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
Presentation
- ____
- Medium
- ____ body
- Used with ____ tray
heavy
light
custom
Dispensing of Impression
• Squeeze ____ lengths of base and catalyst onto mixing pad
equal
Mixing
• Mix with stiff spatula to a ____ color
uniform
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
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 25m • 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
