DMD Dental Materials Science

Question 1

Which time-dependent deformation property of dental amalgam refers to its slow permanent distortion under sustained compressive stress?

Accepted Answer

Creep

Answer

Creep is the time-dependent permanent deformation of amalgam under sustained load, contributing to marginal deterioration over time.

Question 2

Which impression material sets through an irreversible chemical reaction and cannot be reconverted to its original state for reuse?

Accepted Answer

Alginate

Answer

Alginate is an irreversible hydrocolloid — once it gels through an irreversible chemical reaction, it cannot be returned to its sol state.

Question 3

The primary setting reaction of zinc phosphate cement involves which chemical process?

Accepted Answer

Acid-base neutralization

Answer

Zinc phosphate cement sets by an acid-base neutralization reaction between zinc oxide powder and phosphoric acid liquid, forming zinc phosphate crystals.

Question 4

The silane coupling agent incorporated in composite resins primarily functions to:

Accepted Answer

Bond inorganic filler particles to the organic resin matrix

Answer

Silane acts as a bifunctional molecule, bonding the inorganic filler particles to the organic resin matrix and improving the mechanical properties of the composite.

Question 5

Which property of a dental material specifically describes its resistance to permanent surface indentation?

Accepted Answer

Hardness

Answer

Hardness is defined as resistance to permanent deformation or indentation of the surface, commonly tested by Vickers, Knoop, or Brinell methods.

DMD - Doctor of Dental Medicine Practice Test

DMD - Doctor of Dental Medicine Practice Test

DMD Dental Materials Science