Week 7 PP Flashcards
Hydophilic?
Likes water.. material is okay with saliva
Hydrophobic?
Does not like water - mouth must be completely dry
How long can non-treated gingival cords stay in the mouth/gingival sulcus?
15 mins
How long can treated gingival cords stay in the mouth/gingival sulcus?
up to 7 mins
What is Elastomeric material used for?
Bite registration
consits of a base & a catalyst - comes in an automix tip
Rubber like material - comes in different colours from different manufactures
What are the 3 types of impressions?
Preliminary Impression (Reproduction)
Final Detail
Record of occlusion (bite registration)
What are the 4 forms of materials?
Light Body - very thin, records fine tooth detail, wash or syringe
Regular Body - medium viscosity, tray filler
Heavy Body - thick viscosity, tray filler
Putty - thickest/highest viscosity, tray filler
What is a Final Impresion used for?
Used to produce the most accurate reproduction of the teeth and surrounding tissue
- Provides the dentist and dental lab tech the essential information needed for creation of:
-indirect restorations
-implant retained crowns
-custom posts
-partial or full dentures
What is Light Body material?
-Very thin
-lowest viscosity
-records fine tooth detail
-applied directly on the prepared tooth
Technique used: wash or syringe
What is Regular Body material?
Has a medium viscosity
can record fine detail
Tray filler - applied on the tray
What is Heavy Body material?
has a thick viscosity
does not record fine detail
tray filler
What is Putty material?
Has the thickest / highest viscosity
kneaded with hands
tray filler
Final Impression Facts
- set up 2 different viscosities (light body {tooth} & heavier body {tray})
-follow dentist RX
-always bleed the material prior to use
-follow manufacture instructions, expiry dates
-follow IPC (plastic barrier and/or disinfect twice)
-do not mix and match brands
Types of Elastomeric Impression Materials?
- Polysulfide
- Polyether
- Condensation Silicone
- Addition Silicone (polyvinyl siloxane)
What is Polysulfide material?
-known as rubber base
-available in various viscosities
-supplied as a two-paste system: base & catalyst
-has a strong odor and can easily stain clothing
-long working and setting times (10-20 mins)
What is Polyether material?
-Very stiff, difficult to remove from the mouth
*a thinner is included in kit to reduce the thickness of the mix and imiprove the finished impression
-unpleasant smell
-moisture sensitive
-the tubes are not the same size
What is Silicone material?
- Odor-free, non staining, easy to mix
- Good dimensional stability.
- Supplied as base and the catalyst
- Various viscosities available
- Limited shelf life
- Adhesive needed
- More flexible … may distort
- Shrinks over time
What is Polysiloxane material?
- Odor-free, non staining, easy to mix
- Highest dimensional stability
- Supplied as base and the catalyst
- Various viscosities available
- Stiff … not easy to remove
What are the curing stages?
- Initial set - able to mix, getting stiff, not set yet = load the tray
- Final set - changes from elastic to solid rubber = must be seated in the mouth
- Final cure - 1 to 24 hours= small dimensional change
What are the 4 Dispensing systems?
- Paste system (manual mix)
- Auto mix (dispensing gun)
- Mixing unit system (self mix)
- Putty System (manual mix)
What is the Paste Dispensing System?
- manual mixing and loading
with spatula - voids and bubbles
- bigger set up
- base and catalyst tubes
- different viscosities
What is the Automix Dispensing System?
- base and catalyst together
- mixing gun
- loading easier
- reduced voids and bubbles
- different viscosities
What is the Mixing Unit Dispensing System?
- Controlled dispensing: No excess material on the pad
- Versatility: A variety of materials can be mixed and dispensed from this unit
What is the Putty dispensing system?
- very heavy viscosity
- tray filler
- material is kneaded with the hands
Digital Impressions
Scans teeth and surrounding tissues: lasers/light sources
2 methods:
* Digital photo
* Digital video
* many advantages! quick, errors reduction
* many disadvantages as well ! .. price, training….
