Chapter 7 B: Class II Preparation For Composite Resin

Question 1

Advantages of using composites in class II?

Answer 1

• better aesthetics
• conservative tooth preparation
• strengthening remaining tooth structure
• bonding tooth-composite

Question 2

Problems with composites for class II?

Answer 2

• in deep sub gingival extension cases
• in teeth with heavy occlusal contact on the composites

Question 3

Most common forms of design?

Answer 3

(6)
Conventional
Saucer
Box
Tunnel
Slot
Buccal access

Question 4

Conventional preparation:

Answer 4

Steps:
- prepare the occlusal part similar to class I, but proximal box depends on extent of caries, contour of proximal surface and masticatory stress
- for proximal box, extend the preparation using a straight fisure but onto the marginal ridge, keep it perpendicular
- thin out the marginal ridge, deepen the preparation towards the gingival direction —>proximal ditch cut, width of 1-1.5mm
- either break or keep the point of contact depending on the lesion
- gingival floor flat
- either give or dont gingival bevelling depending on the location and width of gingival seat

Question 5

proximal box preparation in a conventional preparation depends on?

Answer 5

extent of caries, contour of proximal surface and masticatory stress

Question 6

When do you preserve and when do you break the point of contact in a conventional preparation ?

Answer 6

• in a small caries leave it, in a large one break it

Question 7

What determines whether we give gingival bevelling or not?

Answer 7

The location and width of gingival seat:

1. If the gingival seat is supra gingival and above the CEJ, bevelling can be done
2. If the gingival seat is close to the CEK, bevelling is avoided to preserve the enamel , if you’re too close to the CEJ and you bevel down, there will be no enamel

Question 8

Saucer shaped preparation is indicated when ?

Answer 8

There’s minimal caries present, deepen the preparation only to the extent of the carie
Concave

Question 9

Box shaped preparation is indicated when?

Answer 9

The caries are only present on the proximal surface, and it’s prepared without the need of secondary retention features , just follow shape of caries

Question 10

Slot preparation is indicated when ?

Answer 10

When the proximal caries can be approached from the facial or lingual sides rather than occlusal

Bur kept perpendicular to the long axis of the tooth and entry to the lesion is made through facial or lingual, cavosurface of 90

Question 11

Tunnel preparation advantages ?

Answer 11

• maintains the point of contact with the adjacent tooth, avoiding having to rebuild it
• not aggressive

Question 12

Objective of tunnel preparation ?

Answer 12

• preserve the marginal ridge and minimise the destruction of dental structure adjacent to the carious tooth

Question 13

Disadvantages of tunnel preparation?

Answer 13

• uncomfortable manipulation of the instruments inside the preparation
• difficult viewing access
• difficult to completely eliminate carious tissue and difficult to fill without leaving traces of air—> secondary caries
• access to light might be compromised

Question 14

Buccal access preparation indication:

Answer 14

Very useful when the caries is not large, and close to the gingiva, and away from point of contact

Question 15

Disadvantage of buccal access preparation?

Answer 15

• hard to hold mirror and turbine is such a small space, complicated technique, difficult to perform on distal surface of molars