Class II Composite Preparations

Question 1

What is a Class II lesion?

Answer 1

Cavities/restorations on the proximal surfaces of premolars and molars.

Question 2

What tool is important for detection and diagnosis of Class II lesions? What can they not indicate?

Answer 2

Bitewing radiographs

• -> Can not diagnose the current activity of the lesion
• -> Can not detect early subsurface demineralization

Question 3

When viewing a bitewing radiograph, how are visible caries (radiolucencies) rated/labeled?

Answer 3

Numbering 0 - 4.
0 = sound
1 = enamel only
2 = enamel + DEJ
3 = enamel + outer dentin
4 = enamel + inner dentin

Question 4

What are the treatment options for a class II lesion?

Answer 4

1. Prevention and reversal
2. Conservative restoration
3. Conventional restoration

Question 5

What are the two types of class II preparations we work on in Sim clinic?

Answer 5

Ideal Conventional Preparation Class II

Slot Class II

Question 6

When is a composite restoration preferable over amalgam (composite is indicated)?

Answer 6

Need minimal tooth structure loss

Bonding to tooth allows conservation of tooth structure - an amalgam might require a larger size and shape

When good isolation may be achieved

Esthetics

Question 7

What are the disadvantages of composite restorations for class II’s?

Answer 7

Shrinkage
Requires good technique (amalgams are less difficult)
Greater occlusal wear = hard on the composite
Some of the composite components may not be so safe (bisphenol A)

Question 8

How is the tooth prepared?

Answer 8

1. Create access to the faulty tooth structure (caries, defective restoration, fractured marginal ridge, etc)
2. Remove the faulty structure
3. Create the convenience form (retention = bonding)

Question 9

Are wedges necessary for class II preps?

Answer 9

Yep - very helpful. They allow:

1. additional separation
2. tighter contacts in the final restoration
3. protect the rubber dam

Question 10

Is it better to start with the occlusal portion or the proximal portion?

Answer 10

Do the occlusal portion first.

Question 11

In the box form, how do the buccal and lingual walls relate to the proximal surface of the tooth?

Answer 11

They are perpendicular to the proximal surface.

Question 12

How far must the pulpal floor be made below the DEJ?

Answer 12

The pulpal floor must be at a depth of 0.2mm inside the DEJ. On a plastic tooth, that is a total depth of 1.5 mm.

Question 13

Why might it be beneficial to extend the box beyond the contact with the adjacent tooth?

Answer 13

It may simplify the preparation, matrix placement, & contouring procedures. On the plastic teeth, the proximal box’s gingival floor should be 0.25 - 0.5mm below the contact

Question 14

What shape should the axial wall be inside the box form portion of the preparation?

Answer 14

Slight convexity!

Question 15

Should a bevel be placed on the occlusal surface?

Answer 15

No - a thin bevel will be weak under the wear and stress of occlusion

Question 16

What can be used to avoid over-extending of the gingival floor in the proximal box?

Answer 16

The wedge can help be a visual guide.