NDAEB Dental Materials and Equipment 2

Question 1

Alginate impression material is classified as which type of impression material?

Accepted Answer

Irreversible hydrocolloid

Answer

Reversible hydrocolloid

Answer

Elastomeric material

Answer

Non-elastic material

Question 2

What is the correct storage method for an alginate impression before it can be poured with stone?

Accepted Answer

Wrapped in a damp paper towel sealed in a plastic bag

Answer

In open air at room temperature

Answer

Submerged completely in water

Answer

Refrigerated without any moisture

Question 3

Polyvinyl siloxane (PVS) is classified under which category of impression materials?

Accepted Answer

Elastomeric impression material

Answer

Irreversible hydrocolloid

Answer

Reversible hydrocolloid

Answer

Non-elastic zinc oxide eugenol

Question 4

Which type of gypsum product is MOST appropriate for fabricating dies used in crown and bridge construction?

Accepted Answer

Type IV die stone

Answer

Type I dental plaster

Answer

Type II model plaster

Answer

Type III dental stone

Question 5

How does increasing the water-to-powder ratio of alginate primarily affect the mix?

Accepted Answer

Lengthens the setting time and produces a thinner mix

Answer

Shortens the setting time and increases strength

Answer

Has no effect on setting time

Answer

Improves the dimensional stability of the final impression

Question 6

Which type of impression tray provides the MOST accurate result when using polyvinyl siloxane material?

Accepted Answer

Custom acrylic tray with PVS adhesive

Answer

Perforated plastic stock tray without adhesive

Answer

Rim-lock tray with water

Answer

Solid metal stock tray used dry

Question 7

Which material is most commonly used today to fabricate a provisional (temporary) crown after tooth preparation?

Accepted Answer

Bis-acrylic composite

Answer

Zinc oxide eugenol paste

Answer

Polycarboxylate cement

Answer

Acrylic resin powder only