AGD Dental Materials and Application 2

Question 1

Which polymerization shrinkage characteristic of composite resins is most clinically significant?

Accepted Answer

Shrinkage occurs toward the light source

Answer

Shrinkage pulls away from the tooth walls creating gaps

Answer

Shrinkage is greatest in bulk-fill composites

Answer

Shrinkage is eliminated by incremental layering

Question 2

What is the primary advantage of using resin-modified glass ionomer cement (RMGIC) over conventional glass ionomer?

Accepted Answer

Improved physical properties while retaining fluoride release and adhesion

Answer

Higher compressive strength than composite

Answer

Complete elimination of sensitivity

Answer

Better esthetic match than ceramic

Question 3

Which amalgam alloy phase is associated with the greatest dimensional change and corrosion susceptibility?

Accepted Answer

Gamma-2 phase (Sn7-8Hg)

Answer

Gamma-1 phase (Ag2Hg3)

Answer

Gamma phase (Ag3Sn)

Answer

Delta phase (Cu3Sn)

Question 4

A patient presents with a cracked cusp on a maxillary molar. Which indirect restorative material best resists crack propagation?

Accepted Answer

Lithium disilicate ceramic onlay

Answer

Full-coverage porcelain-fused-to-metal crown

Answer

Feldspathic porcelain veneer

Answer

Direct composite onlay

Question 5

What effect does the addition of palladium have in metal-ceramic alloys?

Accepted Answer

Raises the melting range and improves oxidation resistance

Answer

Increases ductility for easier casting

Answer

Reduces the modulus of elasticity

Answer

Increases radiopacity for radiographic detection

Question 6

Which property of zinc phosphate cement makes it suitable as a base under metallic restorations?

Accepted Answer

High thermal insulating capacity protects the pulp

Answer

Its acidic pH provides antibacterial action

Answer

High film thickness seals dentinal tubules

Answer

It chemically bonds to both tooth and metal

Question 7

During impression making, which material requires the use of a custom tray to achieve optimal accuracy?

Accepted Answer

Zinc oxide eugenol impression paste

Answer

Irreversible hydrocolloid (alginate)

Answer

Addition silicone (vinyl polysiloxane)

Answer

Polysulfide rubber