Dental Materials Mcqs - Set 16

1)   The tarnished layer of silver amalgam consists of________________?

a. Sulphides of silver
b. Oxides of tin
c. Chlorides of tin
d. All of the above
Answer  Explanation 

ANSWER: Sulphides of silver

Explanation:
No explanation is available for this question!


2)   Which phase provides maximum strength in hardened mercury/silver alloy ?

a. Silver / Mercury phase
b. Silver / Tin phase
c. Tin / Mercury phase
d. Zinc / Mercury phase
Answer  Explanation 

ANSWER: Silver / Tin phase

Explanation:
No explanation is available for this question!


3)   Copper content in low copper amalgam is________________?

a. 6%
b. 12-30%
c. 29%
d. 19%
Answer  Explanation 

ANSWER: 6%

Explanation:
No explanation is available for this question!


4)   Which of the following silver amalgam alloy have the maximum strength________________?

a. Lathe cut
b. Spherical
c. Admixed
d. Single composition
Answer  Explanation 

ANSWER: Single composition

Explanation:
No explanation is available for this question!


5)   What is the most frequently used restorative material ?

a. Silicate
b. Amalgam
c. Composite
d. Gold
Answer  Explanation 

ANSWER: Amalgam

Explanation:
No explanation is available for this question!


6)   How soon after a moisture contamination does a zinc containing amalgam alloy start expanding________________?

a. 24 hours
b. 1-2 days
c. 3-5 days
d. 7 days
Answer  Explanation 

ANSWER: 3-5 days

Explanation:
No explanation is available for this question!


7)   The percentage of copper in high copper alloy is______________?

a. 10-12%
b. 0-6%
c. 13-30%
d. 20-30%
Answer  Explanation 

ANSWER: 13-30%

Explanation:
No explanation is available for this question!


8)   What is the working time of amalgam?

a. One to two minutes
b. Three to four minutes
c. Five to six minutes
d. Seven to eight minutes
Answer  Explanation 

ANSWER: Three to four minutes

Explanation:
No explanation is available for this question!


9)   Advantage of zinc containing amalgam is_______________?

a. Better handling property
b. Dimensional Stability
c. Resistance to creep
d. Toxicity to pulp and dentin
Answer  Explanation 

ANSWER: Better handling property

Explanation:
No explanation is available for this question!


10)   Discolouration of silver alloy is due to_____________?

a. Tarnish
b. Tarnish and corrosion
c. Wet corrosion
d. Dry corrosion
Answer  Explanation 

ANSWER: Tarnish and corrosion

Explanation:
No explanation is available for this question!


11)   Moisture contamination of amalgam can lead to_____________?

a. Marginal breakdown
b. Shrinkage
c. Delayed expansion
d. increased stresses
Answer  Explanation 

ANSWER: Delayed expansion

Explanation:
No explanation is available for this question!


12)   In a high copper amalgam the phase, which is eliminated is_______________?

a. Gamma 1
b. Gamma 2
c. Gamma 1 and 2
d. No phase is eliminated
Answer  Explanation 

ANSWER: Gamma 2

Explanation:
No explanation is available for this question!


13)   Well premeasured capsules of amalgam can release mercury vapour during_______________?

a. Mulling
b. Carving
c. Condensation
d. Trituration
Answer  Explanation 

ANSWER: Condensation

Explanation:
No explanation is available for this question!


14)   In spherical alloys as compared to lathe cut____________?

a. Less condensing force is required
b. More condensing force is required
c. Both require same condensing force
d. Manipulation is easy
Answer  Explanation 

ANSWER: Less condensing force is required

Explanation:
No explanation is available for this question!


15)   Chronic mercury toxicity results from_____________?

a. Ingestion while removing old amalgam
b. Skin contact
c. Mercury vapour
d. All of the above
Answer  Explanation 

ANSWER: All of the above

Explanation:
No explanation is available for this question!


16)   Increase in the residual mercury in silver amalgam filling can_____________?

a. Cause fracture of the filling
b. Tarnish and corrosion
c. Increase the strength
d. Decrease condensation pressure
Answer  Explanation 

ANSWER: Cause fracture of the filling

Explanation:
No explanation is available for this question!


17)   Which of the following statements about high copper silver alloy compared to conventional alloy is not true ?

a. It has increased tensile and compressive strength
b. It has poor tarnish and corrosion resistance
c. It’s edge strength is greater
d. Mercury content in the final restoration is less
Answer  Explanation 

ANSWER: It has poor tarnish and corrosion resistance

Explanation:
No explanation is available for this question!


18)   Compare to conventional amalgams, spherical amalgams_______________?

a. Require more mercury
b. Require heavy compection forces
c. Have longer setting times
d. None of the above
Answer  Explanation 

ANSWER: None of the above

Explanation:
No explanation is available for this question!


19)   Which of the following phases of dental amalgam has minimum strength____________?

a. Gamma 1
b. Gamma 2
c. Epsilon 1
d. Gamma 3
Answer  Explanation 

ANSWER: Gamma 2

Explanation:
No explanation is available for this question!


20)   The ADA specification No 1 for composition of amalgam alloy recommends______________?

a. 65% silver, 32% tin and 3% copper
b. 49% silver, 32% tin and 19% cooper
c. 65% silver, 29% tin and 5-6% copper
d. None of the above
Answer  Explanation 

ANSWER: 65% silver, 29% tin and 5-6% copper

Explanation:
No explanation is available for this question!


21)   The highest mercury concentration in amalgam filling is found_____________?

a. At the margin of the restoration
b. In the centre of the restoration
c. In the deepest part of the restoration
d. None of the above
Answer  Explanation 

ANSWER: At the margin of the restoration

Explanation:
No explanation is available for this question!


22)   The term trituration means____________?

a. Lysing amalgam alloy
b. Mixing of amalgam alloy and mercury
c. Removal of excess of mercury
d. None of the above
Answer  Explanation 

ANSWER: Mixing of amalgam alloy and mercury

Explanation:
No explanation is available for this question!