Lecture #5

Question 1

Complex Amalgam Restoration (PART 1)

Answer 1

1. Indications (good longevity),
2. Preparation,
3. Resistance/Retention,
4. Restoration

Question 2

1. Indications (good longevity):

Answer 2

▪ Cuspal coverage (better than extended MOD)
▪ If not enough support for a crown
▪ Less expensive
▪ If uncontrolled caries, not want crown
▪ Use as a build-up
▪ Fracture prevention of cracked tooth (tie together = 1 unit)
▪ Endodontically-treated teeth (pulp chamber = good retention)

Question 3

2. Preparation:

Answer 3

▪ Initial survey
▪ Rubber Dam Use
▪ Cusp reduction

Question 4

2. Prep - INITIAL SURVEY

Answer 4

• assess contacts (natural/excursive), height, contour, remove caries
  ● Cusp fracture tendencies = buccal of
  maxillary/lingual of mandibular (non-funct.)

Question 5

2. Prep - RUBBER DAM USE

Answer 5

improve visibility, access, moisture control, patient/staff protection

Question 6

2. Prep - CUSP REDUCTION

Answer 6

● Place depth cuts following tooth contours (peaks/valleys) - 2-2.5 mm deep
(#330 bur - 1.5-1.8 mm)
● Connect depth cuts, flatten enamel (pack amalgam on flat surface)

Question 7

Retention:

Answer 7

resist dislodge ALONG path of placement

Question 8

Resistance:

Answer 8

resist dislodge ALONG DIRECTION OTHER

THAN path of placement

Question 9

3. Resistance/Retention - FEATURES:

Answer 9

bulk (2 mm), walls/boxes/pins/grooves, peripherally-distributed

Question 10

3. Resistance/Retention - CUSP COVERAGE:

Answer 10

o If weak/thin cusp (if lost 2/3 of cuspal incline)

o Need bulk – 1.5 mm = nonfunctional cusp / 2 mm = functional cusp

Question 11

3. Resistance/Retention - AMALGAPINS Indications/Advantages

Answer 11

o minimum O-G height (short crown, young patient)
o no additional equipment needed
o rapid to place
o less chance of pulpal/periodontal perforation
o does not stress dentin or weaken amalgam/tooth

Question 12

3. Resistance/Retention - AMALGAPINS Disadvantages

Answer 12

o may fracture if matrix is moved (not stable) or removed too early
o risk of voids from inadequate condensation
o need more dentin thickness
o decreased tensile strength

Question 13

3. Resistance/Retention - AMALGAPINS Placement

Answer 13

o Place 0.5​-1 mm inside DEJ
o Depth/width approx. #330 bur (1-2 mm deep, 1 mm wide)
o Bevel edge w/ #6 round bur (no sharp edges)
o Parallel external tooth surface
o Place at tooth corners
o Stabilize matrix

Question 14

3. Resistance/Retention - BOXES/WALLS

Answer 14

● Walls parallel
● Retention grooves
● May place additional boxes in buccal or lingual groove

Question 15

4. Restoration

Answer 15

▪ Matrix very stable
▪ Condense thoroughly (esp. around retentive features)
▪ Burnish, remove excess
▪ Remove matrix (stabilize)
▪ Buccal/lingual first, then occlusal
▪ Burnish, check occlusion