Free Properties of Dental Materials MCQs with Answers

• A. Amalgam
• B. Cavity varnish
• C. Composite resin
• D. Silicate

Explanation: Silicate cement has thermal conductivity closest to dentin among these choices.

• A. Deformation of set amalgam during function
• B. Continuing alloying between silver-tin alloy and mercury during the life of restoration
• C. Process whereby alloy is wetted by murcury
• D. Spread of amalgam during packing

Explanation: Dynamic creep is the time-dependent deformation of set amalgam under repeated functional loading.

• A. Complexes with hemoglobinto form methemoglobin
• B. Binds to sulfhydryl groups
• C. Inhibits anaerobic glycolysis
• D. Inhibits hemoglobin synthesis, producing anemia

Explanation: Mercury is toxic mainly because it binds to sulfhydryl groups on enzymes and proteins, disrupting cellular metabolism.

• A. 45-55%
• B. 55-65%
• C. 65-85%
• D. More than 85%

Explanation: Approximately 65% to 85% of inhaled elemental mercury vapour can be retained and absorbed, especially through the lungs.

• A. 6.6 a (ppm k-1)
• B. 11.4 a (ppm k-1)
• C. 14.0 a (ppm k-1)
• D. 25.0 a (ppm k-1)

Explanation: Dental amalgam has a relatively high coefficient of thermal expansion, about 25 ppm/K, compared with tooth structure.

• A. Lungs
• B. Kidneys
• C. Skin
• D. Gastro-intestinal Track

Explanation: The kidneys are a major target and storage site for absorbed mercury, not an important route by which mercury enters the body.

• A. 40 Gpa and 60 - 100 Mpa
• B. 350 Gpa and 10 - 120 Mpa
• C. 21 Gpa and 27 - 55 Mpa
• D. 360 Gpa and 125 - 130 Mpa

Explanation: Dental amalgam has an elastic modulus of roughly 21 GPa and a tensile strength commonly reported in the range of about 27 to 55 MPa.