Cavity Preparation

What is the primary goal of cavity preparation?

• To remove all sound tooth structure

• To create a large cavity for ease of restoration placement

• To remove carious tissue while preserving healthy tooth structure

• To prepare the tooth for root canal treatment

Which of the following is a key difference between cavity preparations for amalgam and composite restorations?

• Composite requires undercuts; amalgam relies on bonding

• Both require identical cavity designs

• Amalgam cavities are always shallower than composite cavities

• Amalgam requires undercuts for retention; composite relies on bonding

The 'resistance form' in cavity preparation is designed to:

• Resist the placement of the restoration

• Prevent fracture of the restoration under masticatory forces

• Make the cavity more aesthetic

• Resist fracture of restoration under static occlusion

Which of the following is essential for achieving proper 'retention form' in an amalgam cavity preparation?

• Smooth, parallel walls

• Divergent walls

• Convergent walls

• Rounded internal line angles

In composite restorations, beveling the enamel margins:

• Makes blending of restoration difficult

• Increases the surface area for bonding

• Weakens the tooth due to more tooth structure removal

• Is only done on posterior teeth

Which of the following is a contraindication for placing a composite restoration?

• High aesthetic demand

• Ability to isolate the tooth

• Subgingival margins

• Small Class I lesions

The 'convenience form' in cavity preparation refers to:

• Making the cavity as small as possible

• Shaping the cavity to allow access for instruments and restorative materials

• Creating undercuts for retention

• Beveling the enamel margins

Which instrument is best used to remove carious dentine on pulpal floor during cavity preparation?

• High-speed handpiece with a diamond bur

• Spoon excavator

• Scaler

• Probe no.9

In Class II cavity preparations for amalgam, the proximal box should have:

• Divergent walls to facilitate insertion

• Convergent walls for retention

• Beveled margins

• No contact with adjacent teeth

For composite restorations, the cavity preparation should:

• Be as extensive as possible

• Include mechanical retention features

• Preserve as much tooth structure as possible

• Should be deep enough for placement of liner and base