Final - Amalgam Materials

Front 1

_____ is an alloy of mercury with another metal

Back 1

amalgam

Front 2

What elements are found in dental amalgam?

Back 2

Mercury (Hg) and silver-tin alloy (Ag-SN)

Front 3

What are the classifications of amalgam?

Back 3

Partical geometry, Cu content and Zn content

Front 4

There are two types of amalgam compositions _____ Cu dental amalgam and ______ cu dental amalgam

Back 4

low, high

Front 5

In low copper dental amalgam what percentage is copper?

Back 5

2-5%

Front 6

In high copper dental amalgam what percentage is copper?

Back 6

(12-13%)

Front 7

What is the percentage in low copper amalgam of zinc? what about in high copper amalgam?

Back 7

low: 1%
high: 0%

Front 8

what amalgam composition is considered "old amalgam"

Back 8

low copper dental amalgam

Front 9

the low Cu amalgam reaction looks like this:
alloy powder + Hg = hardened dental amalgam filling
Is the mercury in a solid, liquid or gas state?

Back 9

(liquid)

Front 10

What is highly corrosive and leads to a weakening of structure (a product of low copper amalgam reaction)

Back 10

SnHg (gamma 2)

Front 11

Why does the SnHg (gamma 2) corrode?

Back 11

has little crystal throughout structure - corrodes like rust

Front 12

What is the most corrosive phase of amalgam?

Back 12

SnHg (gamma 2)

Front 13

T/F ALL amalgams corrode

Back 13

True

Front 14

Is the mercury released into the oral environment when performing filling?

Back 14

no, the mercury reacts with unreacted alloy

Front 15

The high copper amalgam reaction has a different product. what is it?

Back 15

CuSn + AgHg (gamma 1)

Front 16

is CuSn ____-(more/less) corrosive than SnHg (gamma2

Back 16

LESS - much better

Front 17

What are the three particle types?

Back 17

spherical, lathe-cut (regular fine and microfine)
and mixed (admixed)

Front 18

What is an 'ideal' prep' for minimal caries?

Back 18

.3-.5 mm into dentin, 1.5 - 2.0mm deep, use 330 carbide bur, use copal varnish (2 layers at 85%) - could use adhesive liner as alternative, amalgam

Front 19

T/F an ideal prep for moderate caries removes all carious tissue

Back 19

false, extend access laterally until DEJ is noncarious, remove carious dentin

Front 20

For moderate caries, what is placed in the hole you created?

Back 20

place a base (insulator-protects) and then restoration

Front 21

Why do they recommend using a rubber dam?

Back 21

access and visibility
better management
controls moisture
decreasing operating time
eliminates some infection
facilitate licensure

Front 22

What is the order of things you do to do an amalgam filling?

Back 22

anesthesia, isolation, cavity preparation,pulpal protection, condensation, carving, polish and finish

Front 23

What things should a cavity prep have?

Back 23

access the lesion, remove the caries, supports structures, retains material

Front 24

What is the purpose of pulpal protection?

Back 24

seals, insulates, reduces sensitivity, stimulates restorative dentin

Front 25

What 2 things encompas condensation?

Back 25

densification adapatation

Front 26

What is important to remember when carving?

Back 26

establishing contour and anatomy, marginal integrity, restoration of occlusal

Front 27

What are the metal components of the amalgam reactions?

Back 27

Low: Ag, Sn, Hg, - has zinc
High: Ag, Sn, Cu, Hg - no zinc

Front 28

What is the mixing of amalgam called?

Back 28

trituration

Front 29

Ag3Sn (gamma) is (reacted/unreacted)

Back 29

unreacted

Front 30

Describe amalgamation

Back 30

Hg wets the gamma phase particles, mercury reacts with outside of particles -> matrix is formed of mainly (gamma 1) AgSn (gamma 1) - >unreacted particles are capture, all mercury is consumed

Front 31

Are there ANY benefits of corrosion?

Back 31

yes,
seals marginal gaps,
reduces sensitivity
increases longevity
inhibits secondary caries
seals dentin tubules

Front 32

The low copper has zinc and the high copper doesn't. This is because the low copper needs it for:

Back 32

oxidation of other elements in alloy

Front 33

What is the "good" about zinc?

Back 33

clinical evidence suggest zinc containing alloys last 20-50% longer
zinc is an oxygen scavenger
used for processing to suppress oxidation of other elements in alloy

Front 34

What helps to maintain a filling for 20-50% longer?

Back 34

zinc

Front 35

What is the 'bad" about zinc?

Back 35

unreacted zinc left in amalgam can react with water during condensation - the gas release results in delayed expansion (don't use with poor isolation)

Front 36

what is the 'ugly' about zinc?

Back 36

amalgam is unesthetic (pt. acceptance)

Front 37

What are some concerns about dental amalgam?

Back 37

pt. conern of toxicity -
environmental concern (OSHA) - Hg in sewersystem

Front 38

What are the properties of amalgam
____-- compressive strength
________tensile strength

Back 38

high, low
brittle (fractures at margins)
creep - plastic deformation under stress
mechanical stress - chewing
chemical stress - corrosion

Front 39

T/F mercuroscopic expansion lead to Hg release

Back 39

True

Front 40

What does Hg react with in mercuroscopic expansion?

Back 40

AgSn unreacted particles

Front 41

T/F the reaction phase takes up more space (volume increases)

Back 41

True

Front 42

t/f The volume increase is associated with the mercuroscopic expansion

Back 42

true

Front 43

does the amalgam protrude from space with mercuroscopic expansion?

Back 43

yes

Front 44

mercuroscopic expansion can lead to a chemical stress induced ___---

Back 44

creep

Front 45

marginal _______ allows bacteria to penetrate between tooth and restoration - this __ leads to secondary caries

Back 45

microleakage

Front 46

T/F corrosoin of amalgam aids in sealing the gap between tooth and restoration

Back 46

True

Front 47

What type of restoration is the most common (associated with recurrent decay)

Back 47

amalgam

Front 48

What is major reason for replacement of an amalgam filling?

Back 48

secondary caries

Front 49

Should you use an explorer and mirror to look for recurrent caries?

Back 49

NO, evidence show not good enough - it's difficult to tell - many variation among dentists, many wrong decisions have been made.

Front 50

T/F Mercury is ubiquitous in the environment.

Back 50

True

Front 51

T/F small amounts of Hg are ingested daily (water, air food)

Back 51

true

Front 52

t/f The party line - no evidence of health risk from amalgam.

Back 52

true

Front 53

_______- bound mercury is much more dangerous

Back 53

organic

Front 54

When would the patient be at risk?

Back 54

if they have mercury hypersensitivity

Front 55

Is amalgam banded in some european countries?

Back 55

yes

Front 56

Is there a health risk for dental professionals?

Back 56

there is a POTENTIAL health risk, just take necessary precautions

Front 57

When some is mercury hypersensitive what should you watch for?

Back 57

the immune response is usually very low to mercury levels, occurs in very low number of individual (low risk) the reaction is mild and not life-threatening

Front 58

is mercury hypersensitivity (low/high) risk

Back 58

low