Impressions Flashcards
What is the mixing, working and setting time of Honigum light body impression?
what is it’s dimeniosnal change, compression set, Shore-A-hardness, strain in compression?
Mixing time: non, extruded onto tooth
Working time: 2minutes 15 seconds
Setting time: 3minutes 30 seconds
Dimensional change: < or equal 0.5
Compression set: < or equal 0.35
Shore-A-hardness: 47
Strain in compression: 4.5
What is the mixing, working and setting time of Honigum heavy body impression?
what is it’s dimeniosnal change, compression set, Shore-A-hardness, strain in compression?
Mixing time: N/A, just extruded from machine
Working time: 2minutes 15 seconds
Setting time: 3minutes 15 seconds
Dimensional change: < or equal 0.4
Compression set: < or equal 0.5
Shore-A-hardness: 67
Strain in compression: 1.4
What is the viscosity of Honigum Light at low sheer stress? (10 Pascals, eg. at rest)
1520 Pasacal seconds (high viscosity)
What is the viscosity of Honigum Light at high sheer stress (1000 Pascals, e.g. when seating tray)
21 Pascal seconds (low viscosity)
How would you use honigum heavy and honigum light body impressions?
- Syringe light body around tooth
- Load tray with hard body
- Insert tray
Why use the hard body as well as the light body?
- Light body gives detail
- Hard body provides hardness and stability to the impression, and also provides resistance against torsion (twisting)
What is the advantage of Honigum Mono?
- Allows impression to be done while using a single phase (and thus avoid the risks of using a two phase technique such as the light body not bonding to the heavy bonding and having to get the mixing and insertion times correct)
- Does this by having high viscosity and stability with low shear stress similar to heavy body
- Has lower viscosity and flowable like like body at high sheer stress
What is the viscoisty of honigum mono at low shear stress (10 Pascals)?
7210 Pascal seconds
What is the viscosity of honigum mono at high shear stress (1000 Pascals)?
80 Pascal seconds
What is the mixing, working and setting time of Honigum mono impression?
what is it’s dimeniosnal change, compression set, Shore-A-hardness, strain in compression?
Mixing time: N/A
Working time: 2minutes 15 seconds
Setting time: 2minutes 30 seconds
Dimensional change: < or equal 0.4 Compression set: < or equal 0.7 Shore-A-hardness: 47 Strain in compression: 3.0-5.5 (Note this can vary depending on the method of application you use)
What trays are available for impression taking?
Stock trays
- Mechanical retention around rim
- Adhesive fleece (hence no adhesive needed)
- No occlusal stops
- 3 Sizes S M L
Disposable stock trays
- Perforated
- Require adhesive
Triple trays
-Dual arch impression
- Cold cure acrylic trays
- No mechanical retention around rims
- Has occlusal stops
- Essential when stock trays unsuitable but require extra construction cost
How long does adhesive take to dry after being applied to tray?
-10 minutes
Should you use the brush available to paint adhesive on?
- No, infection control can not be re-used (as attached to lid)
- use microbrush
How should you use the dual viscoisty technique in the clinic?
- Assistant fills out tray with heavy body, inform operator when half filled
- Operator removes 2ndary retraction cord, discord first 5mm of light body from mixing tip, syringe light body around margins then over tooth and adjacent teeth, keeping tip below surface
- Seat tray
- Allow 5 minutes set
- Remvoe tray using snap removal
- Wash, water and detergent, remove blood and saliva
- Dry impression and check for defects
- If satisfactory, lab form, place in infection control bag, take down to lab.
What are some impression precautiosn to bear in mind?
- Minimise glove contact with tooth prep
- Clean preps with water spray
- Use nitrile gloves
- undercuts, tori, open embrasures
