chapter 10

Question 1

Pros of amalgam

Answer 1

easy to manipulate, durable, low cost

Question 2

Alloy

Answer 2

a mixture of two metals

• Used in amalgam
  
  • Silver
    
    • copper, tin, zinc

Question 3

Amalgamation

Answer 3

When the allot particles are mixed with mercury

Question 4

Alloy classification

Answer 4

affording to shape of particles

1. irregular
2. Spherical
   
   • require less mercury to wet the particles, set faster
3. Admixed

Question 5

Copper

Answer 5

lessens the brittleness
- Modern alloys are high in copper

Question 6

zinc

Answer 6

inhibits corrosion by reducing oxidation

• in low copper amalgams zinc was responsible to gradual expansion, it there was moisture contamination during placement

Question 7

Desirable features

Answer 7

durable
Similar compressive strength to enamel
inexpensive

Question 8

Undesirable features

Answer 8

unattractive
high thermal conductivity
Dimensionally unstable, Creep
requires tooth support
galvanism

Question 9

Firming phase

Answer 9

amalgam can be carved to the shape of the tooth

Question 10

How long does it take for amalgams to gain maximal strength

Answer 10

24 hours

Question 11

Tin

Answer 11

Used to control the rate of set

Question 12

strength

Answer 12

amalgams are the strongest

• relatively weak in tension and shear
• considered brittle, require adequate bulk

Question 13

Creep

Answer 13

gradual change in shape of the restoration from compression by the opposing dentition

Question 14

Tarnish

Answer 14

oxidation that attacks the surface of the amalgam and extends slightly below the surface

• from contact with oxygen, chlorides, and sulfides
• causes a dark dull appearance, but is not very destuctive
• the rougher the surface the more tarnish
• Low copper= tarnish

Question 15

corrosion

Answer 15

chem. reaction between amalgam and substances in the food or saliva, resulting in oxidation over time

Question 16

____ conductor of hot an cold

Answer 16

good

• in deep cavity prep a base or liner should be used

Question 17

powder and mercury are mixed in a

Answer 17

titrator/ shaker

Question 18

under triturated

Answer 18

dry and crumbly appearance, sets too fast

not completely mixed, causes unrelated particles

Question 19

Over- triturated

Answer 19

too wet and has low resistances to condensation

Question 20

Properly triturated

Answer 20

satin appearance

Question 21

Martix band

Answer 21

used to help contain the amalgam during condensation in a class 2 prep and helps form the proximal contours

Question 22

Tofflemire

Answer 22

holds the matrix band in place around the tooth, enables the operator to tighten the band to the tooth

Question 23

wedge

Answer 23

triangular piece of wood or plastic, inserted into the gingival embrasure. on lingual side because the space is wider

Question 24

mercury can enter the body through

Answer 24

ingestion, direct contact with skin, and inhalation of the vapor