Deck 9: Dental Amalgam

Question 1

When the silver-based alloy used to create dental amalgam is mixed with ________, the reaction that occurs is called amalgamation.

A) a bonding agent
B) an acid etchant
C) methyl methacrylate
D) mercury

Answer 1

mercury

Question 2

The cavity preparation is slightly overfilled during the placement and condensation of amalgam to:

A) allow enough material to carve to contours and remove excess mercury that has been forced to the surface during the condensation process
B) form the initial surface anatomy when the patient occludes against the opposing dentition
C) increase the overall height of the patient's bite
D) make sure no material goes to waste in the amalgam well

Answer 2

allow enough material to carve to contours and remove excess mercury that has been forced to the surface during the condensation process

Question 3

Which of the following may happen if a newly placed amalgam contracts excessively?

A) It can put pressure on the cusps.
B) It will open gaps at the margins, contribute to leakage of fluids and bacteria, and cause sensitivity.
C) It can cause pain with biting pressure.
D) It can result in fracture of the cusps.

Answer 3

It will open gaps at the margins, contribute to leakage of fluids and bacteria, and cause sensitivity.

Question 4

Modern dental amalgams are considered to be high _______ in content compared with their predecessors.

A) silver
B) copper
C) tin
D) zinc

Question 5

High-copper amalgams do not have a _______ phase and are superior in their clinical performance to low-copper amalgams.

A) gamma
B) gamma-1
C) gamma-2
D) gamma-1 or gamma-2

Question 6

It takes up to ________ for most amalgams to gain their maximum strength.

A) 30 minutes
B) 1 hour
C) 12 hours
D) 24 hours

Question 7

Under-triturated amalgam alloy has a ____________ appearance and sets too _________, resulting in a weaker restoration.

A) dry, crumbly; quickly
B) dry, crumbly; slowly
C) wet; quickly
D) wet; slowly

Question 8

Creep is a phenomenon associated with the __________ amalgam alloys.

A) gamma-1 phase seen with high-copper
B) gamma-1 phase seen with low-copper
C) gamma-2 phase seen with high-copper
D) gamma-2 phase seen with low-copper

Question 9

Patients should be advised to avoid chewing on a newly placed amalgam for at least:

A) 8 minutes
B) 8 hours
C) 2 days
D) 2 weeks

Question 10

Spherical alloys require ______ mercury to wet the particles and generally set ______ than lathe-cut particles.

A) more; more quickly
B) more; more slowly
C) less; more quickly
D) less; more slowly

Question 11

Insurance carriers have seen a reduction in the use of dental amalgam for posterior restorations by approximately 40% in the past 15 years, probably because:

A) other direct restorative materials have superior durability, ease of handling, and physical characteristics
B) its wear resistance and compressive strength are inferior to composite resin and glass ionomer cement
C) a study conducted by the National Institutes of Health (NIH) in 1991-1993 concluded that amalgam is not safe for human use
D) concerns by patients about its safety and its lack of esthetics have prompted many patients to request tooth-colored materials

Question 12

In the low-copper amalgams, zinc was responsible for the gradual ________ of the amalgam over time if moisture contamination was present during placement.

A) corrosion
B) tarnish
C) expansion
D) contraction

Question 13

Which of the following statements is true regarding the strength of dental amalgam?

A) Amalgams are stronger in compression than composites but weaker than glass ionomers.
B) Amalgams are relatively weak in tension and shear and therefore require adequate bulk to resist breaking.
C) Some high-copper amalgams gain approximately 80% of their strength in the first hour.
D) High-copper amalgams have a much higher compressive strength than low-copper amalgams once they have completely set at about 24 hours.

Question 14

Polishing of amalgam restorations should be:

A) dry with a light touch
B) dry with heavy pressure
C) wet with a light touch
D) wet with heavy pressure

Question 15

Which of the following statements is true of high-copper amalgams in contrast to low-copper amalgams?

A) High-copper amalgams have more of the gamma-2 product than low-copper amalgams.
B) High-copper amalgams are more durable than low-copper amalgams.
C) High-copper amalgams have more deterioration at the margins than low-copper amalgams.
D) High-copper amalgams have more corrosion than low-copper amalgams.

Question 16

The dental amalgam alloy and mercury are mixed together in a mechanical device called a:

A) condenser
B) triturator
C) carrier
D) plugger

Question 17

Which of the following is true of tarnish?

A) It is very destructive to the amalgam.
B) It results from contact with oxygen, chlorides, and sulfides in the mouth.
C) The smoother the surface, the more it tends to tarnish.
D) Polishing the restoration will increase the tarnish.

Question 18

When spherical high-copper dental amalgam alloys are contrasted with admixed dental amalgam alloys, the spherical alloy:

A) needs approximately 10% more mercury than the admixed alloy for the amalgamation process
B) has very little resistance to condensation into the cavity preparation and feels soft compared with an admixed amalgam
C) displaces a matrix band and keeps it in contact with the adjacent tooth in class II preparations better than admixed amalgams
D) has lower 1-hour and 24-hour compressive strengths than admixed amalgams

Question 19

Which of the following is true concerning mercury safety procedures in the dental office?

A) The elemental mercury used in amalgam is more toxic than organic mercury.
B) Studies have shown mercury levels in most dental offices to be far below OSHA's recommended minimum.
C) Dental offices contribute an insignificant amount of mercury to the environment.
D) A "mercury-free" amalgam is available for use in the United States.

Question 20

Which of the following metals is used to control the rate of set of the amalgam?

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

Question 21

List the advantages and disadvantages of amalgam.

Question 22

Describe the different particle shapes in amalgam alloys.

Question 23

Match the items with the correct description below.

-Strongest phase

A)Gamma phase ( $\gamma$ )
B)Gamma-1 phase ( $\gamma$ 1)
C)Gamma-2 phase ( $\gamma$ 2)

Question 24

Amalgam restorations are a combination of:

A) copper and tin
B) silver and mercury
C) specific amounts of each

Question 25

If an amalgam restoration corrodes, the restoration will:

A) weaken over time
B) stain surrounding tooth
C) break down at the margins
D) All of the above are possible.

Question 26

Amalgam goes through three phases when setting, the weakest of which is the:

A) gamma phase
B) gamma-1 phase
C) gamma-2 phase

Question 27

Match the items with the correct description below.

-Phase that consists of mercury reacting with tin

A)Gamma phase ( $\gamma$ )
B)Gamma-1 phase ( $\gamma$ 1)
C)Gamma-2 phase ( $\gamma$ 2)

Question 28

Match the items with the correct description below.

-The silver alloy phase

A)Gamma phase $\gamma$ )
B)Gamma-1 phase ( $\gamma$ 1)
C)Gamma-2 phase ( $\gamma$ 2)

Question 29

Match the items with the correct description below.

-Phase that is weak and corrodes easily

A)Gamma phase ( $\gamma$ )
B)Gamma-1 phase ( $\gamma$ 1)
C)Gamma-2 phase ( $\gamma$ 2)

Question 30

Match the items with the correct description below.

-Phase that consists of mercury reacting with the silver

A)Gamma phase ( $\gamma$ )
B)Gamma-1 phase ( $\gamma$ 1)
C)Gamma-2 phase ( $\gamma$ 2)

Question 31

Which of the following would not be hygienic when amalgam material is used?

A) The rubber dam is placed.
B) The assistant uses the HVE.
C) Staff wears PPE when handling.
D) The floor is carpeted.

Question 32

High-copper alloys gain about 50% of their strength:

A) after 1 hour
B) after 10 hours
C) after 24 hours
D) immediately

Question 33

Amalgams are higher in compression strength but weaker in:

A) stress and strain
B) flexion and tension
C) tension and shear
D) stress and shear

Question 34

Match the items with the correct description below.

-Phase with the least corrosion

A)Gamma phase ( $\gamma$ )
B)Gamma-1 phase ( $\gamma$ 1)
C)Gamma-2 phase ( $\gamma$ 2)

Question 35

Once amalgam is set, attempts to carve will:

A) damage the margins
B) make the surface shiny
C) seal the margins
D) make the surface dull

Question 36

Properly triturated amalgam will appear:

A) shiny and wet
B) a satiny ball
C) dry and crumbled
D) dry and shiny

Question 37

The wet resin technique could be used under an amalgam restoration to:

A) keep the tooth from staining
B) bond the amalgam to the tooth
C) seal dental tubules
D) decrease sensitivity

Question 38

It is not as necessary to polish today's generation of amalgam restorations because:

A) they are high in copper, which is shiny
B) they are low in copper and don't tarnish
C) they are well burnished to finish them
D) they set faster, so it is not necessary

Question 39

List the main components of amalgam alloy and describe their function.