EFDA Impression Materials and Techniques 2

Question 1

Which impression material is most appropriate for capturing a final impression for a complete denture?

Accepted Answer

Zinc oxide eugenol (ZOE) paste

Answer

Polyvinyl siloxane (PVS)

Answer

Alginate

Answer

Plaster of Paris

Question 2

What is the primary reason polyether impression materials require careful storage conditions?

Accepted Answer

They absorb water and dimensional changes occur in humid environments

Answer

They are sensitive to light exposure

Answer

They release toxic fumes at room temperature

Answer

They harden prematurely if stored above 50°F

Question 3

When mixing addition silicone (PVS) impression material, what should the clinician avoid?

Accepted Answer

Using latex gloves during mixing

Answer

Mixing on a glass slab

Answer

Using an automix cartridge

Answer

Loading the tray within 30 seconds

Question 4

A 'monophase' impression technique using PVS means:

Accepted Answer

The same viscosity material is used in both the syringe and tray simultaneously

Answer

Only light-body material is used throughout

Answer

Two separate appointments are required

Answer

A custom tray is not needed

Question 5

Which property of addition silicone makes it preferred for implant-level impressions?

Accepted Answer

Excellent dimensional stability allowing delayed pours

Answer

Rapid set time under 1 minute

Answer

High compressibility that captures thread detail

Answer

Biocompatibility with titanium

Question 6

What does the term 'snap set' refer to in alginate impressions?

Accepted Answer

A rapid transition from a fluid to a gel state in a short time window

Answer

The sound alginate makes when removed from the mouth

Answer

A technique where the tray is snapped onto the arch quickly

Answer

Slow progressive setting over 10–15 minutes

Question 7

Which of the following tray types is required when using polyvinyl siloxane for a full-arch impression?

Accepted Answer

Rimlock tray with adhesive

Answer

Stock perforated tray without adhesive

Answer

Thermoplastic disposable tray

Answer

Water-cooled metal tray