elastic + imp quiz

Polysulfide

The first elastomeric impression material used in dentistry.

Ethyl alcohol

The by-product of condensation silicone polymerization.

Addition silicone (Polyvinyl siloxane, PVS)

The elastomer also known as PVS.

Lead dioxide

The catalyst component in polysulfide impression materials.

Polyether

The elastomer with the shortest working time and very stiff consistency.

Addition silicone

The most dimensionally stable elastomer.

Polyether

The material that shows syneresis and imbibition.

Poor dimensional stability

The main disadvantage of condensation silicones.

Addition silicone

The impression material with hydrogen gas evolution as a side reaction.

Polysulfide

The elastomer that requires a custom tray.

Addition silicone

The most ideally elastic elastomer.

Polyether

The impression material supplied as two pastes containing sulfonic ester.

Vulcanization

The process of cross-linking polymer chains to form a network structure.

Polysulfide

The impression material with the longest working time.

Polyether

The stiffest elastomer, difficult to remove from undercuts.

10% hypochlorite

The disinfectant of choice for elastomeric impressions.

Condensation silicone

The elastomer with a pleasant odor and no staining.

Release of ethyl alcohol

The primary cause of dimensional instability in condensation silicones.

Polyether

The elastomer that requires blocking of undercuts due to stiffness.

Addition silicone

The elastomer that can produce multiple accurate casts from a single impression.

Polysulfide

Polysulfide polymer (mercaptan) + Lead dioxide → Polysulfide rubber + Water.

Condensation silicone

Dimethylsiloxane + Ortho-ethyl silicate + Tin octoate → Silicone rubber + Ethyl alcohol (by-product).

Addition silicone (Polyvinyl siloxane, PVS)

Hydrogen-containing siloxane + Vinyl-terminal siloxane + Chloroplatinic acid → Silicone rubber (side reaction

Polyether

Polyether + Sulfonic ester → Cross-linked rubber.

Negative reproduction of the oral tissues

What is an impression?

Impression Compound, Zinc Oxide Eugenol, Elastomers, Hydrocolloids

What are the four main types of impression materials?

Ease of manipulation, adequate flow, proper setting, dimensional accuracy, biocompatibility

What are key properties of an ideal impression material?

Inelastic (rigid) and Elastic (flexible)

What are impression materials classified into according to mechanical properties?

Irreversible and Reversible

What are impression materials classified into according to setting mechanism?

Zinc Oxide Eugenol (ZOE), Impression Plaster, Impression Compound

What are examples of inelastic impression materials?

Agar and Alginate

What are examples of elastic hydrocolloid impression materials?

B-calcium sulfate hemihydrate

What is the main component of impression plaster?

Modeling plastic softened by heat

What is another name for impression compound?

Type I and Type II

What are the two types of impression compound?

Beeswax

What is the main ingredient of impression compound?

Zinc oxide and Eugenol

What are the two main reactive components of ZOE impression paste?

Oil of cloves

What replaces eugenol to reduce the burning sensation in ZOE?

Type I (hard) – 10 minutes, Type II (soft) – 15 minutes

What are the final setting times for ZOE pastes?

Syneresis

What is the process of fluid being expelled from a gel structure?

Imbibition

What is the process of water absorption by a gel structure?

Liquefaction at 100°C, Storage at 65–68°C, Tempering at 45°C

What are the three temperature stages in agar conditioning?

Sodium alginate + Calcium sulfate → Calcium alginate + Sodium sulfate

What is the setting reaction of alginate?

2–4.5 minutes depending on type

What is the setting time of alginate?

Poor tear strength and poor dimensional stability

What are the two major disadvantages of alginate as an impression material?