Dental Materials Ch. 6 Flashcards Preview

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Flashcards in Dental Materials Ch. 6 Deck (15)
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1

Which of the following elements is used in the highest amount in an amalgam restoration?
(a) Tin
(b) Copper
(c) Silver
(d) Mercury
(e) Aluminum

(d) Mercury

2

Amalgam is strongest in __________ strength after it has set.
(a) Shear
(b) Tensile
(c) Compressive
(d) Bending

(c) Compressive

3

The elements composing the gamma-two (2) phase (the weakest and most corrosion-prone phase) of the amalgam reaction are:
(a) Silver and tin
(b) Silver and mercury
(c) Tin and mercury
(d) Tin and tin

(b) Silver and mercury

4

The function of silver in the amalgam reaction is to:
(a) Reduce strength and corrosion resistance
(b) Increase strength and corrosion resistance
(c) Minimize oxidation
(d) Maximize oxidation

(b) Increase strength and corrosion resistance

5

Control of the mercury content during mixing and condensing of amalgam must be carefully considered because:
(a) The higher the mercury content, the higher the strength and the lower the marginal breakdown.
(b) The lower the mercury content, the higher the strength and the lower the marginal breakdown.
(c) The higher the mercury content, the higher the strength and the greater the marginal breakdown.
(d) The lower the mercury content, the higher the strength and the greater the marginal breakdown.

(b) The lower the mercury content, the higher the strength and the lower the marginal breakdown.

6

The single most important feature that accounts for the clinical success of amalgam restorations is:
(a) Finish and polish
(b) Marginal seal
(c) Economy
(d) Ease of manipulation

(b) Marginal seal

7

The manufacturers of dental amalgam control all of the following except:
(a) Alloy composition
(b) Rate of setting reaction
(c) Proper trituration technique
(d) Particle size

(c) Proper trituration technique

8

An amalgam restoration that has been finished and polished:
(a) Reduces the ability of plaque to adhere
(b) Resists tarnish and corrosion
(c) Will not have any voids
(d) Is more likely to have continuous margins with tooth
structure
(e) All of the above
(f) a, b, and d
(g) a, c, and d

(f) a, b, and d

9

In the low-copper or traditional amalgam reaction, tin reacts with mercury. In the high-copper amalgam reaction, tin reacts with:
(a) Silver
(b) Copper
(c) Zinc
(d) Mercury

(b) Copper

10

The life expectancy of an amalgam restoration is indirectly related to the size of the restoration. As the restoration increases in size, internal stresses decrease, as does the life expectancy.
(a) The first statement is true; the second statement is false.
(b) The first statement is false; the second statement is true.
(c) Both statements are true.
(d) Both statements are false.

(a) The first statement is true; the second statement is false.

11

Ashley was condensing an amalgam during lab and she noticed that the triturated amalgam had a softer, "mushy" feel. What type of alloy did she most likely use in the mixed amalgam?
(a) Spherical
(b) Lathe-cut
(c) Admixed
(d) Blended

(a) Spherical

12

Just after Jennifer triturated her amalgam, the appearance of it was "crumbly" and dry. It already looked set. The amalgam was most likely:
(a) Mixed with an increased mercury/alloy ratio
(b) Over-triturated
(c) Properly triturated
(d) Under-triturated

(b) Over-triturated

13

Amalgam may be used for a variety of restorative procedures. ALL of the following pertain to the use of amalgam EXCEPT:
(a) Good service to patients at a reasonable cost
(b) For cingulum pit areas on the lingual of anterior teeth
(c) Amalgam cores
(d) Restoring Class I, II, IV, and V caries

(d) Restoring Class I, II, IV, and V caries

14

It has been reported in the scientific literature that ______% of dental patients have a TRUE mercury allergy.
(a) 0.01
(b) 0.05
(c) 0.1
(d) 1.0

(c) 0.1

15

The use of gold foil is limited to small restorations because of its:
(a) Short-term longevity
(b) Low strength compared to other restorative materials
(c) High cost of gold foil compared to other materials
(d) Unique handling characteristics

(b) Low strength compared to other restorative materials