AGD Dental Materials and Biomaterials 2

Question 1

Which polymerization shrinkage direction is most clinically significant in composite restorations?

Accepted Answer

Shrinkage toward the bonded cavity walls

Answer

Shrinkage toward the light source

Answer

Shrinkage away from the cavity walls

Answer

Uniform volumetric shrinkage

Question 2

What is the primary purpose of a silane coupling agent in composite systems?

Accepted Answer

Bond the resin matrix to inorganic filler particles

Answer

Increase filler particle size

Answer

Accelerate photoinitiator activation

Answer

Reduce water sorption

Question 3

Which cement has the highest compressive strength and is most suitable for high-stress core buildups?

Accepted Answer

Composite resin

Answer

Zinc oxide eugenol cement

Answer

Glass ionomer cement

Answer

Resin-modified glass ionomer

Question 4

The Vickers hardness test is most appropriate for measuring hardness of which dental material?

Accepted Answer

Dental ceramics

Answer

Impression materials

Answer

Dental cements

Answer

Elastomeric impression materials

Question 5

Which property of dental amalgam improves over time after placement due to corrosion products?

Accepted Answer

Marginal seal

Answer

Tensile strength

Answer

Surface hardness

Answer

Thermal conductivity

Question 6

What is the setting reaction of zinc phosphate cement?

Accepted Answer

Acid-base reaction forming zinc phosphate salt

Answer

Free radical polymerization

Answer

Ionic crosslinking of polycarboxylate chains

Answer

Chelation of calcium ions

Question 7

Which factor most significantly reduces the working time of polyvinylsiloxane (PVS) impression material?

Accepted Answer

Sulfur contamination from latex gloves

Answer

High humidity

Answer

Low ambient temperature

Answer

High filler content