1. Amalgam

Question 1

What is an alloy

Answer 1

A metal made by combining two or more metals together (can also mix in non-metals as well)

Question 2

Alloys tends to have more advantageous properties such as….

Answer 2

greater strength and resistance to corrosion

Question 3

(T/F) Dental amalgam is not an alloy

Answer 3

F-it is

Question 4

What are the components that make up the alloy for the dental amalgam

Answer 4

• silver
• tin
• copper
• (sometimes zinc/palladium)

Question 5

The alloy is mixed with _ to form dental amalgam

Answer 5

mercury

Question 6

What are the three types of dental amalgam alloys

Answer 6

• conventional lathe- cut alloy
• spherical alloys
• admix alloys (mixture of lathe-cut and spherical particles)

Question 7

Conventional lathe-cut amalgam particles are _ shaped

Answer 7

irregular

Question 8

spherical alloys require (more/less) mercury. This is a (good/bad) thing because…

Answer 8

less… good… Amalgams with lower Hg content have better properties

Question 9

Why do spherical alloys require less mercury compared to conventional lathe-cut

Answer 9

because the particles have a smaller surface area/volume ratio.

Question 10

Spherical alloy particles tend to be more (buttery/brittle) due to the lower conc. of mercury

Answer 10

buttery (or plastic)

Question 11

The most common type of alloy used today is

Answer 11

Admix alloy

Question 12

(T/F) Admix alloy requires considerable force when condensing

Answer 12

t

Question 13

An admix alloy is stronger after a (little/lot) of time passes

Answer 13

a lot

Question 14

An admix alloy can be polished after how long post-setting

Answer 14

24 hours

Question 15

The main component of dental amalgam is what element?

Answer 15

Silver (70%)

Question 16

Silver serves to increase the __ of dental amalgam

Answer 16

strength

Question 17

The next component of dental amalgam that is most abundant next to silver is

Answer 17

tin (16%)

Question 18

Tin is involved in lowering the _ of dental amalgam

Answer 18

expansion

Question 19

The metal that has the 3rd highest % composition in dental amalgam is…

Answer 19

Copper (~13%)

Question 20

The two main roles of copper in dental amalgam is to decrease _ and _

Answer 20

creep and corrosion

Question 21

The 4th and final element in dental amalgam with the lowest %composition is

Answer 21

zinc (

Question 22

The roles of zinc in the alloy is to…

Answer 22

• decrease the formation of oxides during melting*

- Increases the wettability of the particles (increased plasticity) –> stronger margins

Question 23

Having inc in dental amalgam makes the material more prone to…which leads to….

Answer 23

moisture contamination…delayed expansion

Question 24

Silver and tin are (plastic/brittle) adding copper to the mix makes the material more (plastic/brittle)

Answer 24

brittle…plastic

Question 25

High copper alloys are also called (2 names)

Answer 25

phase-diapered alloy and admixed high-copper alloy

Question 26

A high copper amalgam must have between _-_% Cu in it to be considered high copper

Answer 26

9-30%

Question 27

High copper amalgams have (better/worse) strength compared to conventional amalgam

Answer 27

better

Question 28

Why is there better marginal integrity and decreased marginal breakdown for high copper amalgams

Answer 28

because they eliminate the gamma 2 phase

Question 29

Gamma phase is a reaction product of...

Answer 29

unreacted tin and silver

Question 30

Gamma 1 phase is a reaction product of...

Answer 30

silver and mercury

Question 31

Gamma 2 phase is a reaction product of

Answer 31

tin and mercury

Question 32

Rank the 3 gamma phases in order of increasing strength

Answer 32

gamma2-gamma1-gamma

Question 33

The gamma phase most susceptible to corrosion is...

Answer 33

gamma 2

Question 34

What is amalgamation

Answer 34

the process of mixing liquid mercury with alloys

Question 35

What are the two different techniques used by dentists to amalgamate amalgam

Answer 35

triturator and mortar and pestle

Question 36

Define creep

Answer 36

time-dependent strain or deformation that is produced by a stress

Question 37

High copper amalgams (increase/decrease) creep

Answer 37

decrease

Question 38

Amalgams can undergo dimensional changes- amalgam can expand or contract- how can you minimize these changes

Answer 38

proper usage of alloy and mercury

Question 39

What types of dimensional changes are commonly seen in Zn-containing amalgams

Answer 39

delayed expansion

Question 40

what can be used in the alloy to reduce the amount of delayed expansion caused by moisture contamination in a Zn-containing amalgam

Answer 40

tin

Question 41

Amalgam shows (high/low) compressive strength, (high/low) tensile strength, and (high/low) shear strength

Answer 41

high...low...low

Question 42

What is tarnish

Answer 42

process which amalgam restoration surface is dulled or discolored due to the formation of oxide layers

Question 43

What is corrosion

Answer 43

Actual deterioration of a metal caused by the chemical reaction between the metal and its environment (air/water) forming metal compounds or corrosion products

Question 44

What is percolation

Answer 44

Influx of salivary flow into the microscopic gap between the restoration and the tooth (salivary fluids react with copper, tin, and silver)

Question 45

High copper amalgams show (slow/fast) rates of percolation because....

Answer 45

slow because they have less gamma 2 phase

Question 46

(T/F) Amalgam creates a deal dependent of the operator that is user friendly

Answer 46

F- independent of the operator*

Question 47

Know the table on the 2nd to last slide

Answer 47

ok

Question 48

Why are amalgam capsules sealed

Answer 48

to prevent evaporation of mercury

Question 49

Increasing the amount of tin the alloy will (increase/decrease) the amount of corrosion/tarnish

Answer 49

increase

Question 50

Increasing the amount of copper in the alloy will (increase/decrease) the amount of tarnish/corrosion

Answer 50

decrease

Question 51

Increasing the amount of silver will (increase/decrease) the strength of the amalgam

Answer 51

increase

Question 52

Increasing the amount of tin will (increase/decrease) the strength of the amalgam

Answer 52

decrease

Question 53

Increasing the amount of copper will (increase/decrease) the strength of the amalgam

Answer 53

increase

Question 54

Increasing the amount of silver will (increase/decrease) the setting expansion of the amalgam

Answer 54

increase

Question 55

Increasing the amount of tin will (increase/decrease) the strength of the amalgam

Answer 55

decrease

Question 56

Increasing the amount of copper will (increase/decrease) the strength of the amalgam

Answer 56

increase

Question 57

Increasing the amount of silver will (increase/decrease) the creep and flow

Answer 57

decrease

Question 58

Increasing the amount of tin will (increase/decrease) the creep and flow

Answer 58

increase

Question 59

Increasing the amount of copper will (increase/decrease) the creep and flow

Answer 59

decrease

Question 60

Increasing the amount of silver will (increase/decrease) the compressive strength

Answer 60

increase

Question 61

Increasing the amount of tin will (increase/decrease) the compressive strength

Answer 61

decrease

Question 62

Increasing the amount of copper will (increase/decrease) the compressive strength

Answer 62

increase

Question 63

Increasing the amount of mercury will (increase/decrease) the setting expansion

Answer 63

increase

Question 64

Increasing the amount of mercury will (increase/decrease) the compressive strength

Answer 64

decrease

Question 65

Increasing the amount of mercury will (increase/decrease) the flow

Answer 65

increase

Question 66

Increasing the amount of copper with (slow/fast) the rate of percolation... because

Answer 66

slow... because the marginal integrity increases in high copper amalgams