class II amalgam preparation

Question 1

whats a class II lesion?

Answer 1

interproximal lesions between molars or premolars

Question 2

what shape do caries take as they penetrate the enamel,? Dentin?

Answer 2

conde/ triangular shapes

Question 3

what might be going on if a lesion is chalky white or the marginal ridge is discolored?

Answer 3

caries

Question 4

describe a simple class 2 lesion

Answer 4

lesion is only on mesial or distal surface

Question 5

describe a compound class 2 lesion.

Answer 5

lesion is on 2 surfaces. Ex. MO or DO

Question 6

describe a complex class 2 lesion

Answer 6

lesion is on 3 surfaces. Ex MOD

Question 7

when is a simple class 2 possible?

Answer 7

isolated tooth or wide interproximal embrasure

Question 8

if you cannot get convinience of access for a simple class 2, what must you do?

Answer 8

access via occlusal so it turns into a compound class 2

Question 9

remember all preparations need to include what?

Answer 9

proper internal and external outlines, resistance form, convienence form, retention form

Question 10

Class 2 prep is the same as class 1 minus the extension of the proximal walls. What are the objectives for extending the proximal walls?

Answer 10

1. include all caries, faults, or existing restorative material.
2. create 90 deg cavosurface
3. no unsupported enamel
   establish not more than .5 mm. clearance with adjacent proximal surface facially, ligually, and cervically.

Question 11

whats a good way to measure the .5mm clearance?

Answer 11

tip of the explorer

Question 12

What shape should the proximal box be?

Answer 12

inverted truncated cone. Wider at gingival area than the occlusal. Buccal and lingual walls converge.

Question 13

what does the inverted truncated cone provide?

Answer 13

resistance and retention

Question 14

how far should the axial wall be from the proximal opening?

Answer 14

1.5mm, ( use the DET to measure)

Question 15

why do you want the angle of the axial wall to the cervical floor to be slightly obtuse?

Answer 15

it increases thickness of amalgam at the isthmus portion and so increases resistance

Question 16

in regards to the axial pulpal floor angle what can you do to increase resistance form?

Answer 16

take a hatchet to it to make it slightly rounded

Question 17

since the buccal embrasure is alot smaller than the lingual, more of it has to be taken out to make the .5 mm. clearance of the tip of the explorer. To avoid taking too much off tof the buccal cusp, what must you do?

Answer 17

give it a slight reverese S shape

Question 18

So the proximal box walls may be a uniform curve, straight line, or reverse S shaped curce (facially) all depending on what 3 things?

Answer 18

1. occlusal anatomy of tooth
2. position and size of contact area
3. width of embrasures

Question 19

whats a class 2 slot preparation?

Answer 19

a conservative type of preparation which preserves as much tooth structure as possible, access is through the marginal ridge of the affected mesial or distal surface & no further extension to the occlusal surface.

Question 20

what material is used for a class 2 slot preparation?

Answer 20

composite