Crown Prep

Question 1

When to provide extra-coronal restorations

Answer 1

Protect weakened tooth structure
Improve aesthetics
Retainer for fixed bridgework
Indicated by design of RPD
Restore tooth function

Question 2

Principles of tooth preparation

Answer 2

Preservation of tooth structure
Retention and resistance
Structural durability
Marginal integrity
Preservation of periodontium
Aesthetic considerations

Question 3

Finish line configurations

Answer 3

Knife edge
Bevel
Chamfer
Bevelled shoulder

Question 4

Label each region

Answer 4

Sulcular epithelium
Junctional epithelium
Connective tissue
Biological width

Question 5

Axial reduction and finish line of metal crowns?

Answer 5

AR- 0.5mm
FL- chamfer(0.5mm)

Question 6

Axial reduction and finish line of ceramic crowns (porcelain)?

Answer 6

AR-1mm
FL- shoulder(1mm)

Question 7

Axial reduction and finish line of all ceramic crowns (porcelain bonded to aluminia or zirconia)?

Answer 7

AR- 1.5mm
FL- chamfer 1-1.5mm

Question 8

Stages in crown prep?

Answer 8

Occlusal reduction
Separation
Buccal reduction
Palatal/lingual reduction
Shoulder and chamfer finish
Check occlusal surface and clearance

Question 9

When may u not restore tooth with crown

Answer 9

Active caries and perio
More conservative options available
Lack of tooth tissue