MFDS Dental Materials 2

Question 1

The polymerisation shrinkage of conventional composite resins is approximately:

Accepted Answer

1–3%

Answer

0.1–0.5%

Answer

5–8%

Answer

10–15%

Question 2

Which component of amalgam is primarily responsible for its corrosion resistance?

Accepted Answer

Copper

Answer

Tin

Answer

Silver

Answer

Zinc

Question 3

What does the term 'thixotropic' mean when applied to impression materials?

Accepted Answer

Becomes less viscous under shear stress

Answer

Sets faster when heated

Answer

Releases hydrogen gas on setting

Answer

Has permanent deformation on removal

Question 4

Galvanic corrosion in the mouth most commonly occurs between:

Accepted Answer

Two dissimilar metals in contact

Answer

Enamel and dentine

Answer

Porcelain and metal

Answer

Composite and GIC

Question 5

Which property is most important when selecting a luting cement for a post with a long, parallel preparation?

Accepted Answer

Low film thickness

Answer

High film thickness

Answer

High setting expansion

Answer

High solubility

Question 6

The process of 'stress relaxation' in impression materials refers to:

Accepted Answer

Decrease in internal stress over time under constant strain

Answer

Dimensional change on storage

Answer

Increased stiffness after setting

Answer

Water sorption during storage