Amalgam Restoration

Question 1

Unique about amalgam longevity

Answer 1

Seals more over time due to its corrosion

Question 2

Percent of allergies to amalgam

Answer 2

1%

Question 3

Contraindications

Answer 3

Aesthetic places, small or medium isolated lesions

Question 4

Advantages of amalgam

Answer 4

affordable, easy to use and place

Question 5

Risk of amalgam

Answer 5

not proven

Question 6

Disadvantages

Answer 6

more complex and technical which leads to less conservation of teeth, non-esthetic, potential for galvanic reactions (dissimilar metals and saliva is conductor), potential for marginal breakdown, poor edge strength, non-insulating, negative perception

Question 7

Edge strength of amalgam

Answer 7

Poor

Question 8

Biocompatibility of amalgam

Answer 8

bioinert or mildly irritating

Question 9

leakage of mercury?

Answer 9

No, corrosion seals well

Question 10

amalgam tatoo or stain

Answer 10

mercury that moved to gingiva causes gray color but benign/no histo changes

Question 11

Thermal irritation

Answer 11

possible for amalgam preps placed deep; hot or cold sensativity

Question 12

Spherical Amalgam

Answer 12

atomize liquid alloy; less condensation pressure; high early st. FINISH

Question 13

Lathe Cut

Answer 13

milling or cutting alloy, irregular shaped, more condensation P,proximals

Question 14

Admixed

Answer 14

Properties of both; more P, easier for interproximals, longer working time slower set

Question 15

Amalgam capsules

Answer 15

Upper-liquid mercury
Middle-septum
Lower-alloy powder-contains pestle for mixing

Question 16

Alloy powder contains

Answer 16

Silver, Tin, Copper, some have zinc

Question 17

Tin in powder

Answer 17

highest affinity for mercury

Question 18

highest affinity to mercury

Answer 18

Tin

Question 19

Reduces oxide formation over time

Answer 19

Zinc

Question 20

Problem of zinc

Answer 20

can have delayed expansion in presence of moisture during prep

Question 21

Conventional Setting Reaction

Answer 21

3 phase outcome; finish

Question 22

dimensional change

Answer 22

impacts final adaptation-initial contraction as Hg reacts with alloy and then expansion as setting progresses

Question 23

increase expansion of amalgam

Answer 23

moisture during placement and under trituration

Question 24

reduce expansion

Answer 24

inc. trituration time, more P when condensing, use material with reduced mg/alloy ratio

Question 25

Factors affecting material strength

Answer 25

trituration, high condensation, no porosity (porosity reduces), sufficient mercury content, excess mercury --> increased gamma 2 phase, hardening rate

Question 26

excess mercury

Answer 26

increased gamma 2 phase

Question 27

Sweet spot values for Hg concentration by weight % vary by alloy but normally about

Answer 27

50%

Question 28

ADA spec for amalgam hardening

Answer 28

amalgam reaches 80 MPa within 1 hour

Question 29

Most amalgam fractures happen when

Answer 29

within the first few hours

Question 30

Set in 20 min of almagam

Answer 30

only 6%-don't eat crunchy stuff

Question 31

amalgam reaches 70% by?

Answer 31

first 8 hours

Question 32

MArquette type hardening rate

Answer 32

187 MPa in 1 hour, 431 by 7 days; dispersalloy admixed

Question 33

survival of amalgam

Answer 33

7-15 years on median, larger more complex to the low end, in controlled studies 55-70yrs

Question 34

Amalgam condensation

Answer 34

compact the alloy (inc. density and remove voids-excess Hg and water), adaptation to walls, reduce excess mercury

Question 35

Condenser size

Answer 35

Small condenser needs less P for larger F while larger needs more P; INVERSE RELATIONSHIP

Question 36

F needed for condensing

Answer 36

6-10lbs of force

Question 37

critical factor in amalgam placement

Answer 37

condensation

Question 38

Condensation technique

Answer 38

1. overlap and orderly-use small condenser first 2. overfilling/overpacking-remove with carving 3. Time (too long=increased voids)

Question 39

When condensing class II

Answer 39

condense deepest parts first!!

Question 40

Size condenser to use first

Answer 40

Small then large once more full

Question 41

1 min beyond manufacturers recommendation results in ____

Answer 41

> 30% increase in residual Hg

Question 42

Goal of amalgam carving

Answer 42

reproduce anatomy that results in proper form and function

Question 43

Flash

Answer 43

extension of the restorative material beyond the prep margins (prone to fracture)

Question 44

first instrument for carving

Answer 44

some kind of burnisher

Question 45

When carving should be initiated

Answer 45

before the amalgam has reached its initial set

Question 46

Carve _____ to margins

Answer 46

Parallel- want instrument to have support to avoid ditching

Question 47

Grooves are too deep

Answer 47

thin amalgam = prone to fracture, the potential for exposure of prep walls, difficult to finish or polish

Question 48

over carving effects

Answer 48

soft tissue problems when convexity is lost

Question 49

Smooth at end with

Answer 49

Cotton roll

Question 50

dispersalloy regular set (tituration speed, condensation time, set time)

Answer 50

tituration speed: turtle, 11-17 seconds Condensation time: 3:30 Set time: 4:30

Question 51

Brittle consideration of amalgam

Answer 51

material is brittle so keep > 1.5 mm

Question 52

When done condensing do not forget to

Answer 52

clear the condenser!

Question 53

discard capsules and pessile where

Answer 53

in clear containers

Question 54

Amalgam scraps go

Answer 54

into amalgam scrap containers

Question 55

T/F; amalgams can be polish right away with a rotary instrument?

Answer 55

False; only after 24 hours!!!!