Amalgam Insertion

Question 1

What is Amalgam?

Answer 1

alloy made by mixing mercury (liquid) with a silver-tin metal component (solid)

after the 2 components are mixed together it is initially a plastic consistency that hardens into a solid mass

Question 2

What are the Advantages of Amalgam?

Answer 2

1. ability to self seal
2. wear rate similar to tooth
3. successful restoration under less than ideal placement circumstances
4. less expensive
5. longer lasting

Question 3

How is amalgam classified?

Answer 3

by particle geometry and size: admixed or spherical

by content: high copper or Zinc

Question 4

What are some Attributes of Admixed?

Answer 4

• lathe and spherical cut particles
• tends to stay in place
• requires greater condensation pressure than spherical
• ** early compressive strength less than spherical alloy

Question 5

What are some Attributes of Spherical Alloy?

Answer 5

• No lathe cut particles
• More difficult to place than admixture
• More difficult to get good proximal contact in Class II
• **Less condensation force required than admixture, though condensor with larger nib is required
• Higher early compressive strength
• Final compressive strength is the same as admixture

Question 6

What are the advantages of High Copper Amalgam?

Answer 6

• Less corrosion due to elimination of gamma 2 phase
• Maintains gamma phase- which is most resistant to corrosion and is strongest component
• Less expansion
• Doesn’t require post carve burnishing

Question 7

What are the 4 steps in Amalgam Placement?

Answer 7

Trituration
Condensation
Carving
Finishing

Question 8

What is TRITURATION and its purpose?

Answer 8

it is the process of COMBINING or MIXING liquid mercury with dry amalgam alloy powder
Purpose: coat alloy particles with mercury
which begins the reaction process, rubs oxide film off alloy, and allows for wetting of particles

Question 9

When is a matrix system used?

Answer 9

When a wall or part of a wall needs to be replaced

• confines restorative material within the restoration
• allows for adequate condensation pressure during amalgam placement
• imparts acceptable surface texture to proximal surface while establishing contact

Question 10

What are the Qualities of a Good Matrix?

Answer 10

1. Rigidity
2. Establishment of proper anatomic contours
3. Restoration of correct proximal contact relation
4. Prevention of gingival excess (overhang)
5. Ease of use
6. Ease of removal
7. Stable

Question 11

What are the different types of matrices?

Answer 11

Instrument
Automatrix system
Palodent system
Triodent system
Tofflemire system

Question 12

What’s an automatrix?

Answer 12

its retainerless
bands vary in height and thickness
good for use on cusp replacements

Question 13

What are the advantages of the automatrix system?

Answer 13

convenient, improved visibility, easy placement on facial or lingual

Question 14

what are the disadvantages of the automatrix system

Answer 14

more expensive, additional supplies, not precontoured , may dislodge buildup

Question 15

What’s the Triodent System?

Answer 15

Advantages similar to palodent system
additionally “v shaped jaws” on ring stabilize on top of contoured wedge
rubberized “gripping” material on ring “jaws”
additional pin grip on wedges
disadvantages– expense

Question 16

What is the most commonly used matrix system in the US?

Answer 16

Tofflemire Matrix- consistes of a matrix band and retainer
2 types of retainers = straight and contra angle for lingual
3 types of bands with varying shapes and thicknesses

Question 17

What are the different types of Matrix bands?

Answer 17

COnventional- flat- must be shaped by burnishing for proper contour and contact
Precontoured- must be careful when removing, may break or alter marginal ridge
Dead soft- has no memory

Question 18

what is the proper positioning of the tofflemire matrix?

Answer 18

open end of slide goes towards the gingiva
narrow end towards gingiva
band should not extend more than 1-2mm above the adjacent marginal ridges