Deck 10: Dental Amalgam

Question 1

For what reason have insurance carriers seen a reduction in the use of dental amalgam for posterior restorations by approximately 45% in the past 20 years?

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.

Answer 1

Concerns by patients about its safety and its lack of esthetics have prompted many patients to request tooth-colored materials.

Question 2

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

Answer 2

gamma-2

Question 3

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

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

Answer 3

copper

Question 4

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

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

Question 5

Why is the cavity preparation slightly overfilled during the placement and condensation of amalgam?

A) Increases the overall height of the patient's bite forced to the surface during the condensation process
B) Makes sure no material goes to waste in the amalgam well
C) Forms the initial surface anatomy when the patient occludes against the opposing dentition
D) Allows enough material to carve to contours and remove excess mercury

Question 6

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 7

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 8

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 9

Polishing of amalgam restorations should be:

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

Question 10

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

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

Question 11

What mechanical device mixes the dental amalgam alloy and mercury?

A) Condenser
B) Triturator
C) Carrier
D) Plugger

Question 12

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

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

Question 13

Which of the following is true of tarnish?

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

Question 14

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 15

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.

Question 16

Undertriturated 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 17

Creep is a phenomenon associated with the gamma-_____ phase seen with _____-copper amalgam alloys.

A) 1;high
B) 1;low
C) 2;high
D) 2;low

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

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

Question 20

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

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

Question 21

List the advantages and disadvantages of amalgam.

Question 22

Compared to composites or glass ionomers,amalgams are higher in compression strength but weaker in:

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

Question 23

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

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

Question 24

Match the items with the correct description below.
Phase with the least corrosion

A)Gamma phase (g)
B)Gamma-1 phase (g1)
C)Gamma-2 phase (g2)

Question 25

What is the result if an amalgam restoration corrodes?

A) Weakens over time
B) Stains surrounding tooth
C) Breaks down at the margins
D) All of the above are possible.

Question 26

Why is it not as necessary to polish today's generation of amalgam restorations as it was to polish earlier amalgams?

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 27

Describe the different particle shapes in amalgam alloys.

Question 28

Why is the wet resin technique used under an amalgam restoration?

A) Bond the amalgam to the tooth
B) Keep the tooth from staining
C) Decrease sensitivity
D) Seal dental tubules

Question 29

What will occur if one attempts to carve amalgam once the amalgam is set?

A) Seal the margins
B) Damage the margins
C) Make the surface dull
D) Make the surface shiny

Question 30

Match the items with the correct description below.
Phase that is weak and corrodes easily

A)Gamma phase (g)
B)Gamma-1 phase (g1)
C)Gamma-2 phase (g2)

Question 31

Match the items with the correct description below.
Phase that consists of mercury reacting with tin

A)Gamma phase (g)
B)Gamma-1 phase (g1)
C)Gamma-2 phase (g2)

Question 32

How will properly triturated amalgam appear?

A) A satiny ball
B) Dry and shiny
C) Shiny and wet
D) Dry and crumbled

Question 33

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

Question 34

Amalgam goes through three phases when setting,the weakest of which is the _____ phase.

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

Question 35

Match the items with the correct description below.
Phase that consists of mercury reacting with the silver

A)Gamma phase (g)
B)Gamma-1 phase (g1)
C)Gamma-2 phase (g2)

Question 36

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

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

Question 37

Match the items with the correct description below.
Strongest phase

A)Gamma phase (g)
B)Gamma-1 phase (g1)
C)Gamma-2 phase (g2)

Question 38

Match the items with the correct description below.
The silver alloy phase

A)Gamma phase (g)
B)Gamma-1 phase (g1)
C)Gamma-2 phase (g2)

Question 39

Amalgam restorations are a combination of which alloys?

A) Copper and tin
B) Silver and mercury
C) Specific amounts of each of the above