Deck 5: Dental Amalgam

Question 1

Which component of dental amalgam exists as a liquid in the capsule before trituration?

A) Tin
B) Silver
C) Copper
D) Mercury

Answer 1

Mercury

Question 2

Which of the following statements is true of admixed amalgam in contrast with spherical amalgam? Admixed amalgams

A) contain only irregularly shaped particles, not spherically shaped particles.
B) require more condensation force than spherical amalgams.
C) require less mercury than spherical amalgams.
D) set somewhat faster than spherical amalgams.

Answer 2

require more condensation force than spherical amalgams.

Question 3

High-copper amalgam has about _____ wt % copper.

A) 3
B) 5 to 10
C) 13 to 30
D) 30 to 40
E) 40 to 50

Answer 3

13 to 30

Question 4

________ mercury vapor is released from dental amalgam per day, as a result of chewing.

A) 1 to 2 µg
B) 2 to 4 wt %
C) 50%
D) No

Question 5

How will under-triturated amalgam appear?

A) Dull
B) Soupy
C) Crumbly
D) A and C
E) B and C

Question 6

In its reacted state, little mercury is released from an amalgam. Little free mercury is available to be released from a set amalgam.

A) Statement 1 is correct; statement 2 is correct.
B) Statement 1 is correct; statement 2 is incorrect.
C) Statement 1 is incorrect; statement 2 is correct.
D) Statement 1 is incorrect; statement 2 is incorrect.

Question 7

A freshly mixed mass of amalgam has a puttylike consistency for _____ minutes.

A) 1 to 2
B) 4 to 5
C) 9 to 10
D) 15

Question 8

What is tarnish?

A) A surface phenomenon
B) Equivalent to corrosion
C) A destructive process that eventually leads to failure of the restoration
D) The result of chemical reactions that penetrate into the body of the amalgam

Question 9

Which of the following statement(s) is(are) true of the property of creep for amalgam restorations?

A) High-copper amalgams have values of creep far above old low-copper amalgams.
B) It is associated with the breakdown of marginal integrity.
C) The ANSI/ADA requires that creep be less than 3%.
D) A, B, and C are true.
E) B and C are true.

Question 10

An admixed dental amalgam contains _______________ shaped alloy powder particles.

A) only irregularly
B) only spherically
C) neither irregularly shaped nor spherically
D) a mixture of irregularly shaped and spherically

Question 11

Which of the following delivery methods for silver amalgam exposes the staff to the least amount of mercury?

A) Mercury added to alloy particles and mixed with a mortar and pestle
B) Silver alloy powder and mercury sealed into a disposable hard plastic capsule
C) Powder compressed into tablets and mixed with mercury in a reusable mixing capsule
D) None of the above

Question 12

Which component of earlier low-copper amalgam caused a significant, unacceptable expansion of amalgam when it was contaminated with moisture during placement?

A) Mercury
B) Copper
C) Silver
D) Zinc
E) Tin

Question 13

In the set mass of amalgam, original silver alloy particles comprise over ____% of the volume.

A) 10
B) 25
C) 50
D) 75
E) 90

Question 14

What is the correct order for the manipulation of amalgam?

A) Carving, condensation, mixing, and finishing
B) Condensation, finishing, mixing, and carving
C) Mixing, condensation, carving, and finishing
D) Mixing, finishing, condensation, and carving

Question 15

Which phase is absent in a high-copper amalgam?

A) ( $\gamma$ )
B) $\gamma$ ₁
C) ( $\eta$ )
D) $\gamma$ ₂

Question 16

Elimination of which compound in the gamma-2 phase of amalgam setting increases clinical longevity in today's high-copper amalgam restorations?

A) Silver-tin
B) Copper-tin
C) Mercury-tin
D) Silver-copper

Question 17

High-copper amalgams have __________________ than low-copper amalgams.

A) more corrosion
B) higher strength
C) better longevity
D) A and C are correct.
E) B and C are correct.

Question 18

What would insufficient strength in a dental amalgam lead to?

A) Tarnish
B) Fracture
C) Expansion
D) Condensation

Question 19

Which of the following is not an advantage of dental amalgam when contrasted with direct resin composite?

A) Longevity
B) Superior esthetics
C) Marginal integrity in subgingival areas
D) Ease of placement in diverse clinical situations

Question 20

Which of the following elements is a liquid at room temperature?

A) Beryllium
B) Mercury
C) Gallium
D) Sodium
E) Lead

Question 21

Which of the following is incorrect regarding admixed alloy?

A) It makes better proximal contacts.
B) It is a mixture of particles.
C) It is easy to condense.
D) It is easier to carve.

Question 22

Which of the following is the most likely route of entry for mercury into the patient and dental personnel during the manipulation of amalgam?

A) Absorption in the gut
B) Contact through skin
C) The lungs as a vapor
D) Intraoral absorption

Question 23

Which of the following is a correct assessment regarding mercury vapor in amalgam?

A) Higher release may occur during the setting reaction.
B) Higher release may occur during removal of old amalgams.
C) Higher release may occur if the amalgam is heated above 80° C.
D) All of the above are correct statements.

Question 24

On average, how much copper is in today's dental alloy?

A) 4%
B) 10%
C) 20%
D) 50%

Question 25

Amalgam should be placed in the cavity preparation by _____________ increments.

A) large to small
B) consistent size
C) small to large

Question 26

Why is it important to use water when polishing an amalgam restoration?

A) Assures integrity of the enamel
B) Produces a high glossy finish
C) So the tooth won't overheat
D) Insures smooth margins

Question 27

Why are ultrasonic condensers discouraged for condensation of amalgam?

A) Increase the evaporation of mercury from the setting amalgam
B) Provide insufficient condensation force
C) Apply excessive condensation forces
D) Traumatize the dental pulp

Question 28

What is the purpose of over-packing the preparation with amalgam?

A) Adequate contour
B) Correct occlusion
C) Closed margins
D) All of the above

Question 29

At 1 day after placement, amalgam's tensile strength most closely resembles which human structure?

A) Bone
B) Dentin
C) Enamel
D) Cementum

Question 30

When should high-volume evacuation be used with dental amalgam?

A) Placing
B) Polishing
C) Removing
D) Doing all of the above

Question 31

How should amalgam scrap be handled?

A) Flushed down the drain with ample water
B) Stored in a sealed container in the refrigerator
C) Disposed of in the trash with other daily refuse
D) Stored in a sealed container containing x-ray developer
E) Stored in a sealed container containing x-ray fixer or another reducing agent

Question 32

The maximum permittable mercury vapor level established by OSHA is _____ mg/m per 40-hour week.

A) 0.05
B) 0.5
C) 5
D) 50

Question 33

Which of the following are characteristics of under-triturated amalgam?

A) Will appear dry and crumbly
B) Does not condense well
C) Is shiny in appearance
D) A and B are correct.

Question 34

Which of the following statements is correct regarding today's dental amalgam?

A) It is high in zinc.
B) It is low in copper.
C) It has high longevity.
D) It has placement issues.

Question 35

How will the mixture appear if amalgam is over-triturated?

A) Puttylike consistency
B) Dry, crumbly mix
C) Wet, soupy mix
D) Hard ball

Question 36

Which of the following is incorrect regarding spherical alloy?

A) It is easy to condense.
B) It sets faster than admixed amalgam.
C) It requires more mercury than admixed amalgam.
D) It makes better proximal contacts than admixed amalgam.

Question 37

Mercury is liquid at room temperature. It is one of two liquid metallic elements on the periodic table.

A) Statement 1 is correct; statement 2 is correct.
B) Statement 1 is correct; statement 2 is incorrect.
C) Statement 1 is incorrect; statement 2 is incorrect.
D) Statement 1 is incorrect; statement 2 is correct.

Question 38

The sum of ________________________ determines the overall dimensional change of an amalgam restoration.

A) compressive strength plus condensation
B) contraction and expansion during setting
C) compressive strength plus tensile strength
D) the amount of tarnish and corrosion produced

Question 39

Which of the following is a component of good mercury hygiene?

A) Using a squeeze cloth to remove excess mercury
B) Using premixed, sealed capsules
C) Handling it only with gloves on
D) Polishing using a dry technique

Question 40

Which component added to silver alloy causes amalgam to expand if contaminated by saliva?

A) Mercury
B) Copper
C) Zinc
D) Tin

Question 41

Of the following, which is an advantage of using spherical amalgam particles?

A) Uses less mercury
B) Easier to condense
C) Sets slower for additional working time
D) Produces a better interproximal contact

Question 42

Compare and contrast expansion and contraction of a newly mixed amalgam.

Question 43

Compare and contrast corrosion and tarnish.

Question 44

Identify the three types of mercury and explain how each is acquired.