Free Properties of Dental Materials MCQs with Answers

• A. Above the proportional limit a material function in a plastic manner, while below the proportional limit it behaves as an elastic
• B. Above the proportional limit a material functions in an elastic manner, while below the proportional limit it behaves as an plastic
• C. Either A or B
• D. Neither A or BConsult Online Doctors

Explanation: Below the proportional limit, stress is directly proportional to strain and the material returns to its original form, so behaviour is…

• A. Amalgam
• B. Acrylic resin
• C. Gold alloy
• D. Silicate cement

Explanation: Acrylic resin has the highest coefficient of thermal expansion among these materials, so it undergoes the greatest dimensional change with…

• A. Young's modulus
• B. Plastic strain
• C. Elastic strain
• D. Flexural strain

Explanation: Elastic strain is reversible deformation: the material returns to its original form when the applied force is removed.

• A. Slicate cement
• B. Composite
• C. Polycarboxylate
• D. GIC

Explanation: Enamel has a thermal expansion coefficient of approximately 11 ppm/°C, which is closest to that of glass ionomer cement.

• A. Primary forces
• B. Cohesive forces
• C. Secondary forces
• D. Ionic forces

Explanation: Cohesive forces hold atoms or molecules of the same material together, whereas adhesive forces act between different materials.

• A. Adherent and Adhesive molecules are tangent to each other
• B. Rough surfaces between Adhesive & Adherent
• C. Complete wetting of surfaces
• D. Irregularities present between Adherent surfaces

Explanation: A contact angle of zero indicates complete wetting, because the adhesive spreads fully over the adherent surface.

• A. Ductile materials
• B. Flexible materials
• C. Malleable materials
• D. Brittle materials

Explanation: The Brazilian test, or diametral compression test, is used to estimate tensile strength in brittle materials that are difficult to grip in…

• A. Liquid should wet solid surface
• B. Mechanical interlocking should be present
• C. Should have high contact angle
• D. None of the above

Explanation: For a liquid adhesive to bond to a solid, it must wet and spread over the surface, which requires a low contact angle.

• A. Define and measure colour qualitatively
• B. Measures different colours quantitatively
• C. Evaluate brittleness of different alloys
• D. Define and measure physical properties of gold alloys

Explanation: The Munsell system describes colour using hue, value and chroma, allowing colours to be specified quantitatively.

• A. Resilience
• B. Toughness
• C. Maximum flexibility
• D. Elastic limit

Explanation: The strain at the proportional limit represents the material's maximum flexibility in this terminology.

• A. Thixotropic
• B. Pseudoplastic
• C. Newton
• D. Dilatant

Explanation: Dilatant liquids are shear-thickening materials, so their apparent viscosity and rigidity increase as the rate of deformation rises.

• A. Greater ductility
• B. More resistance to permanent deformation
• C. A higher modulus of elasticity
• D. A higher modulus of elasticity
• E. Greater toughness

Explanation: A higher proportional limit means the material can withstand greater stress before leaving elastic behaviour and undergoing permanent…

• A. Dentin
• B. Amalgam
• C. Enamel
• D. Composite Resin

Explanation: Enamel has the greatest modulus of elasticity among these choices, so it is the stiffest.

• A. Surface tension of the adherent
• B. Surface texture of the adherent
• C. Surface energy of the adherent
• D. Nature of the adherent that is crystalline or amorphous

Explanation: Wetting depends strongly on the surface energy of the adherend: high surface energy promotes spreading of the adhesive and better contact.

• A. Gold inlay
• B. Acrylic resin
• C. Gold foil
• D. Silicate cement

Explanation: Silicate cement has a coefficient of thermal expansion close to that of tooth structure, reducing temperature-related dimensional mismatch…

• A. Solid directly to gas
• B. Gas to liquid and then to soild
• C. Gas directly to liquid
• D. Solid to liquid and then to gas

Explanation: Sublimation is a phase change in which a solid changes directly into a gas without passing through the liquid state.

• A. Ability to be stretched with permanent deformation
• B. Rigidity or stiffness of the material
• C. Ductility of a material
• D. Malleability of the metal

Explanation: The modulus of elasticity is the stress-to-strain ratio in the elastic range and indicates how stiff or rigid a material is.

• A. 90°
• B. >90°
• C. 0 - 90°
• D. 0°

Explanation: Complete wetting means the liquid spreads fully over the solid surface, producing a contact angle of 0°.

• A. Tensile strength
• B. Elongation
• C. Modulus of elasticity
• D. Modulus of resilience

Explanation: For dental gold alloys, hardness generally rises with tensile strength because both increase with strengthening of the alloy.

• A. VHN
• B. KNH
• C. RHN
• D. BHN

Explanation: The Knoop hardness test uses an elongated diamond indenter and is suitable for brittle materials, with its hardness value largely…