Principles pf Crown Preparation

Question 1

What are the principles of crown preparation?

Answer 1

1. Preservation of tooth tissue
2. Retention and resistance
3. Structural durability
4. Marginal integrity
5. Preservation of the periodontium
6. Aesthetic considerations

Question 2

Why should tooth structure be preserved?

Answer 2

Avoids unnecessarily weakening the tooth and damage to the pulp

Question 3

What does under preparation result in?

Answer 3

Poor aesthetics
Over built crown with periodontal and occlusal consequences
Restorations with insufficient thickness

Question 4

What does over preparation result in?

Answer 4

Pulp and tooth strength being compromised

Question 5

Describe the ideal taper of a crown prep

Answer 5

Inclination of opposing walls of 6-10 °

Question 6

What can influence retention and resistance of a crown prep?

Answer 6

Taper
Length of the walls
Path of insertion
Extra means of retention - grooves and slots

Question 7

How can retention be improved in crown prep

Answer 7

By limiting the number of paths of insertions

Question 8

How is structural durability of a crown prep achieved?

Answer 8

Occlusal reduction
Functional cusp bevel
Axial reduction

Question 9

Which crown line configurations are mostly used?

Answer 9

Chamfer and shoulder

Question 10

How should the margins of a crown prep be?

Answer 10

Smooth and fully exposed to a cleansing action
Placed where the dentist can finish them and the patient can clean them
Placed supragingival or subgingivally when possible

Question 11

What should be considered in crown prep for aesthetics?

Answer 11

Which material:
Provides the best aesthetics - will the restoration be visible?
Has the least destructive preparation?
Is least destructive to opposing teeth?
Is best suited to bruxists?