The term "trituration" means:
A. Lysing amalgam alloyB. Mixing of amalgam alloy and mercury
C. Removal of excess of mercury
D. None of the above
Dynamic creep is the:
A. Continuing alloying between Silver-Tin alloy and mercury during the life of the restorationB. Deformation of set amalgam during function
C. Process whereby alloy is wetted by mercury
D. Spread of amalgam during packing
The highest mercury concentration in amalgam filling is found:
A. At the margin of restorationB. In the centre of the restoration
C. In the deepest part of the restoration
D. None of the above
The dental amalgam is most resistant to:
A. Compressive stressB. Impact stress
C. Shear stress
D. Tensile stress
The ADA specification no. 1 for composition of amalgam alloy recommends:
A. 65% silver, 32% tin and 3% copperB. 49% silver, 32% tin and 19% copper
C. 65% silver, 29% tin and 5-6% copper
D. None of the above
According to ADA sp. no. 1, the minimum compressive strength for silver amalgam after one hour should be:
A. 80 MpaB. 140 Mpa
C. 260 Mpa
D. 510 Mpa
Which of the following phases of dental amalgam has minimum strength?
A. Gamma 1B. Gamma 2
C. Gamma 3
D. Epsilon 1
Admixed high copper alloy powder contains:
A. 9-20% copperB. 13-20% copper
C. 9-30% copper
D. 13-30% copper
Compared to conventional amalgams, spherical amalgams:
A. Require more mercuryB. Require heavy compaction forces
C. Have longer setting time
D. None of the above
Finishing and polishing of amalgam causes ___________ of the restoration.
A. Increase in tarnish and corrosion resistanceB. Increase in the marginal strength
C. Decrease the tarnish and corrosion resistance
D. Increase in the compressive strength
Which of the following statements about high copper silver alloy compared to conventional alloy is not true?
A. It has increased tensile and compressive strengthB. It has poor tarnish and corrosion resistance
C. Its edge strength is greater
D. Mercury content in the final restoration is less
Setting time of amalgam is best controlled by:
A. Using spherical particlesB. Lathe cut alloy
C. Altering Hg-alloy ratio
D. Trituration time
Increase in the residual mercury in silver amalgam filling can:
A. Cause fracture of the fillingB. Cause tarnish and corrosion
C. Increase in strength
D. Decrease condensation pressure
High Cu alloys have all of the following except:
A. High tensile strengthB. Low creep
C. High corrosion
D. None of the above
Chronic mercury toxicity results from:
A. Ingestion while removing old amalgamB. Skin contact
C. Mercury vapor
D. All of the above
In non zinc containing dental amalgam alloy, the percentage of zinc present is:
A. Less than 0.02 %B. Less than 0.1 %
C. Less than 0.01 %
D. None of the above
In spherical alloys as compared to lathe cut:
A. Less condensing force is requiredB. More condensing force is required
C. Both require same condensing force
D. Manipulation is easy
High copper dental amalgams are superior to other amalgams because high copper dental amalgams:
A. have less marginal breakdownB. are workable at lower Hg-alloy ratio
C. have a higher ratio of tensile to compressive strength
D. have less resistance to tarnish and corrosion
Well premeasured capsules of amalgam can release mercury vapor during:
A. MullingB. Carving
C. Condensation
D. Trituration
The largest component of amalgam alloy is:
A. SilverB. Tin
C. Zinc
D. Copper
In a high copper amalgam, the phase which is eliminated is:
A. Gamma 1B. Gamma 2
C. Gamma 1 and Gamma 2
D. No phase is eliminated
During amalgamation, trituration is done to:
A. dissolve the alloy in mercuryB. coat the alloy particles with mercury
C. remove excess mercury from amalgam
D. dissolve Hg in alloy
Moisture contamination of amalgam can lead to:
A. Marginal breakdownB. Shrinkage
C. Delayed expansion
D. Increased stresses
Amalgam restorations give the best clinical service when the residual mercury content is:
A. 38-42%B. 48-52%
C. 58-62%
D. 68-72%
Discoloration of silver alloy is due to:
A. TarnishB. Tarnish and corrosion
C. Wet corrosion
D. Dry corrosion
Percentage of tin in low copper alloy is:
A. 30-35%B. 26-28%
C. 13-32%
D. 22-30%
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