Quiz 8 Stuff - modified DO and DOL preps

Question 1

Upper molar: Why is extension to the oblique ridge avoided whenever possible?

Answer 1

To maintain the cross splinting strength it provides to the tooth.

Question 2

Upper molar: Cutting through ridge indications:

Answer 2

Ridge undermined with caries
crossed by deep fissure
Occlusal portion of the separate MO and DO outline forms leaves insufficient tooth structure between them.

Question 3

class II cavity :
occlusal depth:
axial wall depth:

buccal, lingual, gingival clearance:

Answer 3

occlusal depth: 1.5 - 2.0 mm
axial wall depth: 1.2 mm - 1.5 mm MD

b, l, g clearance: .5 - 1.0 mm

Question 4

class II cavity : lingual extension:

pulpal floor:
axial wall depth:
axial wall:

Answer 4

pulpal floor: 1.5 - 2 mm
axial wall depth: 1.0 mm BL at lingual extension
Axial wall: .5 mm into dentin

Question 5

Where should the vertical wall of a prep be placed in modified DO?

Answer 5

On upward incline of the adjacent cusp

Question 6

How many retentive grooves for amalgam in maxillary molar?

Answer 6

4.
2 within the distal box area
2 within lingual extension

Question 7

When to use modified cavity class II prep?

Answer 7

When caries extend towards the small distal cusp > 2/3 the distance.

Question 8

Areas of cusp replacement reduced _ mm at mininum:

why do u do this?

Answer 8

2 mm

to avoid fracture of amalgam. For resistance.

Question 9

How many retentive grooves for mandibular molar?

Answer 9

3.

axio-buccal line angle
axio-lingual line angle
-distal wall. 0.25 mm at deepest point and fade out at the DEJ