Par 3 - Complex Amalgam Restorations

Question 1

T/F? Expansion & contraction of amalgam is better than composites.

Answer 1

TRUE.

Question 2

Indications for Complex Amalgam Restorations?

Answer 2

1. large amts of tooth structure missing & when 1 or more cusps need capping
2. questionable pulpal or periodontal prognosis
3. teeth w/ acute and severe caries
4. definitive final restorations
5. foundations for full coverage indirect restorations

Question 3

Contraindications for Complex Amalgam Restorations?

Answer 3

1. significant occlusal probs
2. tooth cannot be restored properly w/ a direct restoration bc of anatomic or functional consideration
3. esthetics
4. pt concerns about mercury

Question 4

What is the basic composition of amalgam?

Answer 4

silver-mercury (Ag2Hg3) matrix w/ filler particles of silver-tin (Ag3Sn)

Question 5

What makes gamma (y), gamma 1 (y1), and gamma 2 (y2)?

Answer 5

gamma (y): Ag3Sn - filler
gamma 1 (y1): AgHg3 - matrix
 gamma 2 (y2): Sn8Hg - matrix - weak link!

Question 6

3 types of amalgam alloy?

Answer 6

1. lathe cut
2. spherical
3. admixture

Question 7

Why is higher copper content amalgam better?

Answer 7

Bc it has less gamma 2 phase (weakest phase)

Question 8

T/F? Spherical amalgam has less mercury.

Answer 8

TRUE.

Question 9

T/F? Spherical amalgam has less strength than admix amalgam at 15 minutes.

Answer 9

FALSE. It has higher strength at 15 min (good for immediate amalgam cores for crowns).

Question 10

T/F? Spherical amalgam feels softer during condensation & requires less pressure & larger diameter condensers.

Answer 10

TRUE.

Question 11

*Which is NOT an indication for a complex amalgam?

Answer 11

occlusal problems

• other contraindications:
  1. significant occlusal probs
  2. tooth cannot be restored properly w/ a direct restoration bc of anatomic or functional consideration
  3. esthetics
  4. pt concerns about mercury

Question 12

*Which matrix system does NOT use a retainer?

Answer 12

AutoMatrix

Question 13

*What is the necessary bulk for amalgams?

Answer 13

1.5 to 2mm

Question 14

*Which are forms of secondary retention?

Answer 14

All of the Above

• possible answers: grooves, slots, locks, coves, pot holes, boxes, retention pins, bonding

Question 15

*Which of these is NOT true about polishing amalgam?
A. inc'd smoothness
B. dec'd plaque retention
C. dec'd corrosiveness
D. dec'd thermal conductivity

Answer 15

D. dec’d thermal conductivity

- this doesn’t change!