Free Restorative Materials MCQs with Answers

• A. 38-42%
• B. 58-62%
• C. 48-52%
• D. 68-72%

Explanation: Amalgam generally provides the best clinical service when the residual mercury content is approximately 48 to 52%.

• A. 35 pounds
• B. 3 pounds
• C. 15 lb
• D. 25 lb

Explanation: Amalgam is commonly condensed with approximately 3–5 pounds of pressure, enough to adapt the material and express excess mercury without…

• A. Ag
• B. Cu
• C. Zn
• D. Hg

Explanation: Copper strengthens the amalgam matrix and reduces the weak tin-mercury phase, so increasing copper raises strength and hardness.

• A. Requires least amount of mercury
• B. Achieves high compressive strength at 1 hr.
• C. Has tensile strength both at 15 minutes and 7 days is comparable to high copper, unicompositional alloys
• D. Has lower cree value

Explanation: Lathe-cut low-copper alloys generally require more mercury and develop lower early compressive strength than high-copper alloys, but their…

• A. Creep value of all the above mentioned alloys is same
• B. Admix alloy
• C. Single composition alloys
• D. Low copper amalgam alloy

Explanation: Low-copper amalgams have the highest creep because they retain more of the weak gamma-2 tin-mercury phase.

• A. 8 hours
• B. 4 hours
• C. hours
• D. 16 hours

Explanation: Amalgam gains strength gradually after placement and reaches about 70% of its ultimate strength at approximately 8 hours.

• A. All of the above
• B. Trituration time
• C. Speed of amalgamator
• D. Amalgam alloy

Explanation: The effect of trituration on amalgam strength depends on the alloy formulation, trituration time and mixing speed.

• A. Decreased compressive, increased strength
• B. It increases compresssive and tensile strengths
• C. Decreased compressive, decrease tensile strength
• D. Increased compressive, increased tensile strength

Explanation: Amalgam margins should have a 90-degree butt-joint cavosurface angle so the material has adequate bulk and is supported by tooth…

• A. Low compressive strength
• B. High marginal breakdown
• C. High creep
• D. Less marginal #

Explanation: High-copper amalgams eliminate or greatly reduce the weak gamma-2 phase, producing lower creep and much less marginal breakdown.

• A. Galvanism
• B. Pulp exposure
• C. Improper amalgam filling
• D. None of the above

Explanation: Contact between dissimilar metals such as amalgam and gold in the presence of saliva can produce a galvanic cell, causing an electric…

• A. Tensile strength
• B. Compressive strength
• C. Corrosion
• D. Creep

Explanation: Amalgam performs well clinically mainly because it tolerates heavy occlusal forces through its high compressive strength.

• A. From smooth atomized particles
• B. From lathe cut particles
• C. From irregular and spherical particles
• D. From traditional alloy particles

Explanation: High-copper amalgam can be made by admixing irregular or lathe-cut silver alloy particles with spherical silver-copper eutectic particles.

• A. Remove oxides from powder particle surface
• B. Achieve a workable mass of amalgam in minimum time
• C. Pulverize pelletes into particles to aid in attack by mercury
• D. Keep the amount of gamma-1 or gamma-2 matrix crystals to maximum

Explanation: Trituration should produce a workable amalgam and expose alloy surfaces for mercury reaction, while reducing undesirable phases such as…

• A. Mercury
• B. Tin
• C. Silver
• D. Zinc

Explanation: Gallium and indium are used in mercury-free alloy systems, where they act as liquid metals in place of mercury.

• A. Requires least amount of mercury
• B. Achieves lowest compressive strength at 1 hr.
• C. Has tensile strength both at 15 min & 7 days comparable to high copper unicompositional alloy
• D. Has low creep

Explanation: Traditional lathe-cut silver alloy particles require more mercury and develop strength more slowly than many spherical or high-copper…

• A. Dry Mix
• B. None of the above
• C. Short Mixing Time
• D. Shiny Mix

Explanation: A properly triturated amalgam mix is cohesive and shiny because the alloy particles have been adequately wetted by mercury.

• A. 6%
• B. 12-30%
• C. 29%
• D. 19%

Explanation: Low-copper amalgam contains less than about 6% copper, so 6% is the intended classification value.

• A. Lathe cut
• B. Single composition
• C. Admixed
• D. Spherical

Explanation: Single-composition high-copper alloys generally provide the greatest strength because they eliminate the weak gamma-2 phase throughout the…

• A. Silicate
• B. Composite
• C. Amalgam
• D. Gold

Explanation: Amalgam has traditionally been the most frequently used direct restorative material because it is durable, relatively inexpensive, and…

• A. 24 hours
• B. 1-2 days
• C. 7 days
• D. 3-5 days

Explanation: When zinc-containing amalgam is contaminated with moisture before setting, hydrogen generation causes delayed expansion that becomes…