Impression Materials
•Register or reproduce the ____ of teeth and oral tissues
•Register the _____ of the teeth to__ ___r and to the ___ ___ surrounding them
•Impression itself is a ____e reproduction of the structure impressed.
- Impression materials were developed to reproduce the form of teeth and oral tissues*
- This is they way the alginate impression will work*
- Once you finish your impression you can have your positive after you pour a stone or any other material in the imrpession*
- Philip Pfaff in 1756 was the first guy to take an impression.*
- Clinical decesions in impressiong making: do you switch to Digital.*
Impression Materials
- Register or reproduce the form of teeth and oral tissues
- Register the relationship of the teeth to each other and to the oral tissues surrounding them
- Impression itself is a negative reproduction of the structure impressed.
Impression materials were developed to reproduce the form of teeth and oral tissues
This is they way the alginate impression will work
Once you finish your impression you can have your positive after you pour a stone or any other material in the imrpession
Philip Pfaff in 1756 was the first guy to take an impression.
Clinical decesions in impressiong making: do you switch to Digital.
•A positive reproduction is made when the impression is poured with ____
•
•The function of an impression material is to ___ ____ _t_he dimensions of oral tissues and their ___ relationships.
•
•A positive reproduction is made when the impression is poured with stone.
•
•The function of an impression material is to accurately record the dimensions of oral tissues and their spatial relationships.
•
Types of Impressions
- ___
- ___
- ___ ___
P: we always or almost always take this with ___
F: We have ___, ____ ,a polyether, a combo material,
BR: an impression that we take to regiester upper and lower arch. Send to lab so they can relate the cast in the right position and to make a right restoration
Types of Impressions
- Preliminary
- Final
- Bite-registration
P: we always or almost always take this with alginate
F: We have PVS, a PolyS, a polyether, a combo material,
BR: an impression that we take to regiester upper and lower arch. Send to lab so they can relate the cast in the right position and to make a right restoration
Preliminary Impressions may be used for:
- ___ ___
- __ __
- ___
__ ___
•__ and __ ___ ___
Diagnostic models in all the disciplines
Custom tray Is used to use with the final impression. You can use it just for that patient. Tray is made from preliminary impression that you have made previously
Provisional: clear material that inside you can
Thin egg shell or more complex
Provisional: Thin, clear material. Inside this material, you place a material to fill a temporary restoration. Temporary can be thin or more complex
Ortho Appliances: to make a minor movement or retainers
Pre and Post:
They take impression first day for diagnostic
At end of treatment they take another one to compare and keep it for legal purposes
Preliminary Impressions may be used for:
- Diagnostic models
- Custom trays
- Provisional
- Ortho appliances
- Pre and post treatment records
Diagnostic models in all the disciplines
Custom tray Is used to use with the final impression. You can use it just for that patient. Tray is made from preliminary impression that you have made previously
Provisional: clear material that inside you can
Thin egg shell or more complex
Provisional: Thin, clear material. Inside this material, you place a material to fill a temporary restoration. Temporary can be thin or more complex
Ortho Appliances: to make a minor movement or retainers
Pre and Post:
They take impression first day for diagnostic
At end of treatment they take another one to compare and keep it for legal purposes
Final impressions are used to fabricate ___ restorations: Crowns, bridges, inlays/onlays, partial dentures, complete dentures, implants, etc.
Must be of the ____accuracy
Must include ___ information required by the lab to fabricate the restoration
•
Indirect: take impression and send it to the lab
Top to bottom Pictures:
Single Crown or 3 unit bridge
RPD
Complete Denture
Implant: Take impression of impression post. Transfer that to a cast. The restoration can then be done in the lab
You can duplicate existing denture with alginate.
Final impressions are used to fabricate indirect restorations: Crowns, bridges, inlays/onlays, partial dentures, complete dentures, implants, etc.
Must be of the highest accuracy
Must include all information required by the lab to fabricate the restoration
•
Indirect: take impression and send it to the lab
Top to bottom Pictures:
Single Crown or 3 unit bridge
RPD
Complete Denture
Implant: Take impression of impression post. Transfer that to a cast. The restoration can then be done in the lab
You can duplicate existing denture with alginate.
•Bite-registration – used to reproduce the____ relationship of the maxilla to the mandible usually in___ ___/__ ___
•
To take impression of maxilla/mandible occlusal surface
Regisil
Take vertical dimension and CR at the same time
BluMousse
Comes in regular and superfast
•Bite-registration – used to reproduce the occlusal relationship of the maxilla to the mandible usually in maximum intercuspation/ centric occlusion
•
To take impression of maxilla/mandible occlusal surface
Regisil
Take vertical dimension and CR at the same time
BluMousse
Comes in regular and superfast
Ideal Properties of Impression Materials
- A pleasant __ , ___ and___ color
- Absence of __ or __ constituents
- Adequate __ ___ for requirements of storage and distribution
- Economically commensurate with the results obtained…(“_______________k”)
- ___ to use with the minimum of ____
Ideal Properties of Impression Materials
- A pleasant odor, taste, and esthetic color
- Absence of toxic or irritant constituents
- Adequate shelf life for requirements of storage and distribution
- Economically commensurate with the results obtained…(“_best bang for the buc_k”)
- Easy to use with the minimum of equipment
- ___ characteristics that meet clinical requirements
- Satisfactory ___ and ___
- Readily ___ oral tissues
- ____ properties with ___ from permanent deformation after strain
- Adequate ___h so it will not ___ or __\_ on removal from the mouth
- Setting characteristics that meet clinical requirements
- Satisfactory consistency and texture
- Readily wets oral tissues
- Elastic properties with freedom from permanent deformation after strain
- Adequate strength so it will not break or tear on removal from the mouth
11.____l stability over ___ and ____ ranges normally found in clinical and laboratory procedures for a period ____ enough to permit the production of a cast
- Compatibility with ___ materials
- ___ in clinical use
•
11.Dimensional stability over temperature and humidity ranges normally found in clinical and laboratory procedures for a period long enough to permit the production of a cast
- Compatibility with cast materials
- Accuracy in clinical use
•
- Readily ___ without loss of )____
- No release of ____during the setting of the impression or cast
- Readily disinfected without loss of accuracy
- No release of gas during the setting of the impression or cast
Alginates - Not Good for Crown and Bridges
- Low ___ strength
- Not ___ stable
- Less ___
- Won’t__ __
- ___ tray
The reasons are that
They have a low tear strength.
Very small film
When this film goes inside the sulcus and you remove it, almost always that small film is going to stay in the sulcus
If you are not aware of that, the patient can have some sort of gingivitis or abscess
When you take impression, Make sure to check and see that there is no material inside the sulcus
This is especially for the final product.
Large tray compared to custom
Alginates - Not Good for Crown and Bridges
- Low tear strength
- Not dimensionally stable
- Less accurate
- Won’t displace tissue
- Large tray
The reasons are that
They have a low tear strength.
Very small film
When this film goes inside the sulcus and you remove it, almost always that small film is going to stay in the sulcus
If you are not aware of that, the patient can have some sort of gingivitis or abscess
When you take impression, Make sure to check and see that there is no material inside the sulcus
This is especially for the final product.
Large tray compared to custom
All of the brands are pretty much the same
Important thing for different brands is not to mix the brand cylinders
Use the cylinder for the brand that you are using
It will give you the right water/powder ratio
If not mix will be too runny or too grainy
On the right identic: 100 hr stability. (How soon you need to pour the cast)
That is true under special conditions
But it is very useful for Dentist iPL: That means Dentist who have a lab that is not inside the office
Take impression…Take iphone and call the lab to pick up the impression
All of the brands are pretty much the same
Important thing for different brands is not to mix the brand cylinders
Use the cylinder for the brand that you are using
It will give you the right water/powder ratio
If not mix will be too runny or too grainy
On the right identic: 100 hr stability. (How soon you need to pour the cast)
That is true under special conditions
But it is very useful for Dentist iPL: That means Dentist who have a lab that is not inside the office
Take impression…Take iphone and call the lab to pick up the impression
Dustless:When you shake the container, the heavy product in the alginate goes to the bottom. So you can mix it and get a good quality of powder. Dustless means that when you open it the powder wont come at your face
Smaller Cans
Individual pouch. You can use part B as the water dispenser. Don’t need to worry about finding the right cylinder to measure the water
Mix: its one color. As it starts setting, it changes colors. It tells you that its ready to remove from the mouth
Accugel: ___ than the regular alginate. Used for some final impression in RP or complete dentures. Has better quality than regular alginate. Comes with a special tray to use with ___s patient. Comes with a syringe. You need someone to help you. Someone prepare the synringe material. Someone prepare the tray material.
This is the syringe. Place the material in there. White piece can be ___ if yyou are doing impression in the sulcus. If doing impression o ____ suface, use this piece so the material will go ___
Dustless:When you shake the container, the heavy product in the alginate goes to the bottom. So you can mix it and get a good quality of powder. Dustless means that when you open it the powder wont come at your face
Smaller Cans
Individual pouch. You can use part B as the water dispenser. Don’t need to worry about finding the right cylinder to measure the water
Mix: its one color. As it starts setting, it changes colors. It tells you that its ready to remove from the mouth
Accugel: Better than the regular alginate. Used for some final impression in RP or complete dentures. Has better quality than regular alginate. Comes with a special tray to use with edentulous patient. Comes with a syringe. You need someone to help you. Someone prepare the synringe material. Someone prepare the tray material.
This is the syringe. Place the material in there. White piece can be removed if yyou are doing impression in the sulcus. If doing impression of occulsal surface, use this piece so the material will go straight
Chemistry of Hydrocolloids
- Sol phase - ___of___ particles dispersed in___
- Gel phase ____ of___ particles with ___ in spaces
- Irreversible gelation - gel forms by ____e chemical reaction
They get into a sol phase.
When you start mixing, it gets into a gel phase
Once material is in gel stage, this is irreversible. You can’t go back to powder
Chemistry of Hydrocolloids
- Sol phase - solution of colloidal particles dispersed in liquid
- Gel phase - framework of solid particles with liquid in spaces
- Irreversible gelation - gel forms by irreversible chemical reaction
They get into a sol phase.
When you start mixing, it gets into a gel phase
Once material is in gel stage, this is irreversible. You can’t go back to powder
Chemistry of Hydrocolloids
•____ - adsorption (___) of water, ___
•__\_ - continued reaction, ___, exudate ___ setting of gypsum
If you place impression in water for a long time, material will absorb the water forever. It will get bigger.
If you leave it out of water (on the bench), it will shrink bc its losing the water
Chemistry of Hydrocolloids
•Imbibition - adsorption (hydrophilic) of water, expansion
•Syneresis - continued reaction, shrinkage, exudate retards setting of gypsum
If you place impression in water for a long time, material will absorb the water forever. It will get bigger.
If you leave it out of water (on the bench), it will shrink bc its losing the water
Alginate - Composition
- ____ ___– (18%) – To ___ in water and react with ___ ions
- ___ ___ ___ – (14%) – To react with ___ ___to form an insoluble __ __ ___
- ___ ___, ___, or ___ – (10%) - accelerator for___
- ___ ___ – (2%) - ____r, reacts with ___ ions (___/___ ___g time) ___ or ___ Set
K-alginate: mix with the water and will make the rxn with the Ca ions.
K sulfate: when you pour the stone, it will accelerate the setting of the stone
Sodium phosphate, we don’t have any control, the company places the amt to control if its regular set or fast set or superfast set
Alginate - Composition
- Potassium alginate – (18%) – To dissolve in water and react with calcium ions
- Calcium sulfate dihydrate – (14%) – To react with potassium alginate to form an insoluble calcium alginate gel
- Potassium sulfate, silicates, or borates – (10%) - Accelerator for gypsum
- Sodium phosphate – (2%) - Retarder, reacts with calcium ions (provides/controls working time) Fast or Regular set
K-alginate: mix with the water and will make the rxn with the Ca ions.
K sulfate: when you pour the stone, it will accelerate the setting of the stone
Sodium phosphate, we don’t have any control, the company places the amt to control if its regular set or fast set or superfast set
- Diatomaceous earth or __ __ – (56%) – Controls ___ of ___ and___ of ___
- Organic glycols – (Small) - Coating to ___ ___, ___
- Wintergreen, peppermint, anise – (Trace) -___
- Pigments – (Trace) -__
- Disinfectants – (1-2%) – ____n of viable organisms
If you look at silicate powder under the microscope you can see beautiful form.
Organic Glycols so the powder wont go up
- Diatomaceous earth or silicate powder – (56%) – Controls consistency of mix and flexibility of impression
- Organic glycols – (Small) - Coating to minimize dust, inhalation
- Wintergreen, peppermint, anise – (Trace) - Taste
- Pigments – (Trace) - Color
- Disinfectants – (1-2%) – Disinfection of viable organisms
If you look at silicate powder under the microscope you can see beautiful form.
Organic Glycols so the powder wont go up
Alginate - Setting Reaction
- __ __e + __ __ __ + ___ –> __ __e (gel) + __ __
- Calcium alginate is ___e in water and cannot return to the ___ state
- Acceleration - ___ water, fast-set product
Remember the K sulfate in contact with the stone will start the mix
Regular Set:
To make it faster setting, we place a little bit of warm water. It will speed the reaction is if its a regular set
If its a fast, set you already need to move really quickly
If you make cold water, it will take a long time to set
That is our only control in the clinic of set time
Alginate - Setting Reaction
- Potassium alginate + calcium sulfate dihydrate + water –> calcium alginate (gel) + potassium sulfate
- Calcium alginate is insoluble in water and cannot return to the sol state
- Acceleration - warm water, fast-set product
Remember the K sulfate in contact with the stone will start the mix
Regular Set:
To make it faster setting, we place a little bit of warm water. It will speed the reaction is if its a regular set
If its a fast, set you already need to move really quickly
If you make cold water, it will take a long time to set
That is our only control in the clinic of set time
Alginate Techniques
•Proportioning (water/powder ratio) - measure, add ___ to ___ (adjust water amount for proper ___)
•Mixing – ___(use a ___ ___)
•Loading the tray - minimize ___ entrapment, ___ surface (__ ___)
- Proportioning (water/powder ratio) - measure, add powder to water (adjust water amount for proper consistency)
- Mixing – stropping (use a beavertail spatula)
- Loading the tray - minimize air entrapment, smooth surface (wet finger)
Alginate Techniques
- Placing the tray in the mouth - ___ to ___ (Use a __ __r N_OT __ __!)_
- Removing the tray - __, ___ motion (use the “___” test…no ___)
- Preparing the impression for a gypsum model – rinse saliva with ___ water
Dont use finger if you have shrek fingers, theres not enough room.
Stressful for the patient
Wiggling will distort the material
Alginate Techniques
- Placing the tray in the mouth - posterior to anterior (Use a mouth mirror N_OT YOUR FINGER!)_
- Removing the tray - smooth, fast motion (use the “fingernail” test…no wiggle)
- Preparing the impression for a gypsum model – rinse saliva with cold water
Dont use finger if you have shrek fingers, theres not enough room.
Stressful for the patient
Wiggling will distort the material
al
- Storage of the impression - ___% ___. in ___
- Disinfection of the impression - ___n or ___
- Storage of the impression - 100% R.H. in container
- Disinfection of the impression - immersion or spray
•Working time
–regular-set ___ min
–fast-set ___ min
•Setting time
–regular-set___ min
–fast-set ___ min
•Working time
–regular-set 2-4 min
–fast-set 1.25-2 min
•Setting time
–regular-set 2-4.5 min
–fast-set 1-2 min
- Elastic recovery - >___%
- Flexibility - ___%
- Tear strength - ____ g/cm
- Dimensional stability - best to pour model ___
- Elastic recovery - >95%
- Flexibility - 8-15%
- Tear strength - 400-700 g/cm
- Dimensional stability - best to pour model quickly
- Incorrect water/powder ratio - unpredictable ___ & properties…(Really?)
- Under mixing - ___ mix, poor ___ __, ___t setting
- Over mixing - sets before seating tray
- Incorrect water/powder ratio - unpredictable setting & properties…(Really?)
- Under mixing - grainy mix, poor surface detail, inconsistent setting
- Over mixing - sets before seating tray
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Mechanical Properties19
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Physical Properties40
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Optical Properties39
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Composition and Properties of Dental Amalgam39
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Resin 125
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Resin II28
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Bonding Agents30
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Noble Metal Alloys22
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Elastomeric Impression Materials27
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Gypsum35
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Glass Ionomers37
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Alginate27
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Dental Cements49
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Pituitary Gland42
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Casting and Soldering Investments58
