2. Amalgam Finishing and Polishing

Question 1

How is finishing a restoration performed?

Answer 1

by primarily evaluating the restoration for any flaw and make necessary modifications if needed

Question 2

When should finishing be done

Answer 2

the day the restoration is placed

Question 3

(T/F) Finishing is commonly performed with hand and rotary instruments

Answer 3

t

Question 4

Define polishing a restoration

Answer 4

smoothing the surface to a point of high glosser luster

Question 5

Does polishing an amalgam restoration pose a clinical advantage with a high copper amalgam except for having a smoother surface that is more comfortable to the patient

Answer 5

no- clinical outcome is the same

Question 6

(t/f) A finished restoration should be smooth and have no overhanging margins

Answer 6

t

Question 7

What are the 3 purposes of finishing

Answer 7

Ensure that

• There is no uneven area between the amalgam and restoration margin and the cavity prep wall
• Contour and occlusion are correct
• Smooth restoration

Question 8

What is the purpose of polishing

Answer 8

to achieve high smoothness for the comfort of the patient

Question 9

Why is it that polishing will not enhance the clinical outcome of a high copper amalgam if it is finished well

Answer 9

Because the high copper amalgams are less susceptible to corrosion (elimination of the gamma II phase)

Question 10

Polishing should be done how long after finishing the restoration

Answer 10

24 hrs

Question 11

Why wait 24 hrs to polish a restoration

Answer 11

this is how long it takes for amalgam to fully set

Question 12

What two techniques may serve as substitutes to polishing

Answer 12

pre-carve burnishing and post-carve burnishing

Question 13

Should the restoration be smooth after finishing before polishing?

Answer 13

Yes

Question 14

Why is condensation of amalgam so important

Answer 14

because you don’t want gaps/voids in the restoration. Condensing will allow the amalgam to adapt to the prep walls and the matrix (when used) to be free of voids

Question 15

Voids/gaps in the restoration can lead to…

Answer 15

marginal leakage

Question 16

Proper condensation of amalgam offers what benefits (4)

Answer 16

• prevents marginal leakage
• reduces excess mercury content (thus leading to a reduction in corrosion, increase in strength, and increase in marginal integrity)

Question 17

The little condenser is used (when) and a large condenser is used (when)

Answer 17

• Little= when finishing the restoration

- Large= when overpacking the restoration

Question 18

(T/F): You don’t need to condense each increment of amalgam separately

Answer 18

f

Question 19

Describe the pattern of condensing strokes you should take

Answer 19

-Each stroke should overlap the previous to make sure the amalgam is well adapted

Question 20

By how much should the restoration be overpacked by

Answer 20

1 mm

Question 21

Why do you overpack a restoration

Answer 21

to ensure the cave-surface margins are completely covered with well condensed amalgam (don’t want an under contoured restoration as well)

Question 22

How long should condensing take

Answer 22

2.5-3.5 minutes

Question 23

What should you do if you want to use more amalgam be it has already began to set in the well

Answer 23

-Quickly mix a new amalgam because it will not react well with the amalgam that has already been condensed because it has began crystalizing

Question 24

Condensing should be done with (heavy/light) pressure

Answer 24

heavy

Question 25

Knowing the amount of pressure that needs to be used to condense the amalgam is determined by two factors which are...

Answer 25

- diameter of the condenser | - type of amalgam

Question 26

Spherical amalgam requires a (large/small) condenser... why?

Answer 26

large because using a small condenser will penetrate a mass of spherical amalgam and that will cause less effective force to adapt the amalgam to the walls

Question 27

Admix amalgams require (large/small) condensers and why

Answer 27

small because the material is more resistant to condensation pressure

Question 28

The smaller the condenser the (more/less) force needs to be applied.... if you double the diameter of the condenser the amount of force needed to attain the same amount of pressure is _ times as (great/less)

Answer 28

less...4x great

Question 29

What should you do to ensure the amalgam is well condensed before carving

Answer 29

Pre-carve burnishing: burnish immediately with a large burnisher with heavy strokes both MD and BL

Question 30

The purpose of pre-carve burnishing is...

Answer 30

ensure denser amalgam at the margin and bring out excess mercury and increase the marginal adaptation of the restoration

Question 31

To maximize the efficacy of pre-carve burnishing what should you do

Answer 31

make sure the head of the burnisher is large enough so that the head touches the cusp slopes but not the margin for the final strokes.

Question 32

What are the names of the hand instruments that are used to carve amalgam

Answer 32

- cleoid/discoid - Walls no. 3 carver - Hollenback - Interproximal carver (IPC) - No. 14L sickle-shaped carver

Question 33

During carving the edge of the blade must be _ to the margin of the prep

Answer 33

perpendicular

Question 34

Why is it important to keep part of the edge of the blade of the instrument on the unprepared tooth when carving

Answer 34

prevents overcharging and continues continuity of restoration

Question 35

The carver should be pulled in what direction when carving

Answer 35

parallel to the margin of the prep (stroke should be from enamel to amalgam)

Question 36

(T/F) you want to the tooth and amalgam surfaces to be even (no step down)

Answer 36

t

Question 37

Why is having flash bad?

Answer 37

because it is a thin piece of amalgam that will chip away and damage the margin making it more prone to marginal leakage

Question 38

What should the margin of the prep mimic

Answer 38

the cavosurface margin

Question 39

what is post-carving burnishing

Answer 39

the light rubbing of the surface of a carved amalgam restoration with a burnisher (PKT3 burnisher)

Question 40

Post carve burnishing should be done with a (large/small) burnisher

Answer 40

small

Question 41

(T/F) Post carving burnishing produces a smoother and shinier restoration surface

Answer 41

f- smoother but NOT shinier

Question 42

When should the dentist perform the finishing step of the restoration

Answer 42

the same day of the restoration

Question 43

What does the finishing step consist of

Answer 43

checking occlusion and evaluating margins with an explorer

Question 44

A heavy contact with occlusion paper looks like

Answer 44

A dark circle with a shiny center

Question 45

(T/F) new amalgam shouldn't have any heavy contact points

Answer 45

T- they should have light contacts

Question 46

Carbide burs, white alumina stone and green carborundum stone are for (finishing/polishing)

Answer 46

finishing

Question 47

Which is more abrasive the green carborundum or the white alumina

Answer 47

green carborundum

Question 48

The long axis of the stone should be _ to the margin of the restoration when finishing

Answer 48

perpendicular

Question 49

Why are the ends of finishing burs/stones rounded

Answer 49

prevent the destruction of occlusal anatomy that was created when carving

Question 50

Since the surface must be smooth before it is polished, if the restoration has many irregularities, what can you do

Answer 50

use wet pumice and prophy cups as a pre-polishing step followed by tin-oxide and water or alcohol for high luster

Question 51

What are the disadvantages of using the pumice for pre-polishing

Answer 51

splatter

Question 52

What are the names of the two "burs" in our kits that can be used for both finishing and polishing

Answer 52

- brownie | - mini greenie

Question 53

What are the names of the carbide burs we have for finishing

Answer 53

- Bullet - Neumeyer - Egg - Long pear

Question 54

The son-lex discs are good for finishing/polishing _ surfaces

Answer 54

convex

Question 55

The abrasive impregnated polishing cups and tips can be used for polishing what kinds of surfaces

Answer 55

convex surfaces such as cusp tips (cups) and occlusal surfaces (tips)

Question 56

(T/F) there shouldn't be any stretches on the amalgam when you get to the rubber cups/tips

Answer 56

t

Question 57

Rubber points and cups need to be used at (low/high) speed with coolant

Answer 57

low

Question 58

Why is it important that the rubber points don't overheat the amalgam restoration

Answer 58

- Rubber points disintegrate at high speeds - Overheating the restoration can lead to plural damage - Generation of heat brings liquid mercury to the surface causing excessive volatilization of mercury and weaker amalgam surface and increasing the likelihood of corrosion.