CVC Intro (22)

Question 1

Preparation definition

Answer 1

The final shape to receive a restoration

Question 2

Complete veneer crown preparation

Answer 2

Extracoronal preparation involving the entire clinical crown

Question 3

Complete veneer crown

Answer 3

A cast-gold extracoronal which covers the clinical crown

Question 4

Path of withdrawal

Answer 4

The imaginary line along which a casting is moved when it is separated from its single crowns preparation
Should be nearly coincident with the tooth’s long axis
Want it to be +/- 5 degrees

Question 5

Axial wall

Answer 5

Part of a crown prep prepared in the long six of the tooth - can be designated as buccal, lingual, mesial, or distal

Question 6

Convergence angle

Answer 6

The angle or taper formed by diametrically opposed axial walls
Should be ~6 degrees

Question 7

Chamfer

Answer 7

The cervical junction of the prepared axial wall and the unprepared portion of the tooth structure.s. Extends around the most cervical portion of the tooth prep.

Question 8

Line angles

Answer 8

Lines formed by the junction of any two tooth surfaces. Should be rounded in a CVC prep

Question 9

Axial wall line angle

Answer 9

The junction between 2 axial walls

Question 10

Occlusoaxial line angle

Answer 10

The junction between the occlusal surface and an axial wall

Question 11

Cavosurface line angle

Answer 11

The junction of prepared and unprepared tooth

This is an external line angle

Question 12

Depth orientation grooves

Answer 12

Grooves placed on the surface of the tooth to provide a reference to determine when sufficient tooth structure has been reduced

Question 13

Functional cusp bevel

Answer 13

A wide bevel placed on the functional cusps, the thickness of which ensures that correct contours of the final restoration be re-established while providing correct convergence and adequate thickness of materials

Question 14

Undercut

Answer 14

A crown preparation is undercut if a wax pattern cannot be withdrawn from its die without distortion

Question 15

Occlusal clearance

Answer 15

The distance between the occlusal surface of the prepared tooth and the occlusal surface of the opposite tooth.
This is evaluated during excursive jaw movements as well as in as well as in intercuspal position

Question 16

Retention form

Answer 16

The characteristics of the tooth preparation which tends to resist the removal of a restoration along its path of withdrawal

Question 17

Resistance form

Answer 17

The characteristics of a tooth preparation which tends to prevent dislodgment of a seated restoration by force in an optical or oblique direction.

Question 18

CVC Advantages

Answer 18

High strength
Longevity
High resistance to displacement
Ability to modify axial contours an occlusion

Question 19

CVC Disadvantages

Answer 19

Display of metal
Removal of tooth substance
Vitality testing
Margin close to gingival tissue which can lead to inflammation

Question 20

CVC indications

Answer 20

Extensive destruction by caries or trauma
Endodontically treated teeth
Large existing restorations
Maximum retention needed
Recontouring of axial surfaces
Correction of malinclination
Correction of occlusal discrepancies
To provide contours suitable for a removable partial denture

Question 21

CVC contraindication

Answer 21

Wherever a tooth can be adequately restored with a more conservative restoration

Question 22

Principles of tooth preparation

Answer 22

Conservation of tooth structure
Marginal integrity of the restoration
Adequate retention and resistance
Structural durability

Question 23

Conservation of tooth structure

Answer 23

Minimum tooth reduction compatible with adequate strength and correct contour

Question 24

Marginal integrity of the restoration

Answer 24

The tooth restoration interface at the gingival margin is a potential site of failure due to cement dissolution or roughness. The prep should be designed to enable a smooth, strong, well-adapted casting to be provided

Question 25

Excessive tooth reduction will occur if...

Answer 25

- the tooth is peeped with excessive convergence - the prep does not follow the anatomy of the tooth - the POW diverges from the long axis of the tooth - Excessively wide margin - Excessive gingival extension

Question 26

Inadequate marginal integrity will occur if...

Answer 26

- The chamfer is too narrow to provide sufficient bulk of restorative material without over contouring - The cavo-surface line angle cannot easily be determined during laboratory procedures - The chamfer is rough or uneven - The preparation is undercut causing distortion of the wax pattern

Question 27

Causes of inadequate retention and resistance

Answer 27

- Excessive convergence angle - Inadequate height and surface of the axial walls - Insufficient surface area to resist tipping

Question 28

Functional cusps recommended and acceptable range

Answer 28

1. 5 mm | 1. 3-1.7mm

Question 29

Central groove thickness

Answer 29

1. 0mm | 0. 8-1.2mm

Question 30

Non-funcitonal cusp thickness

Answer 30

1. 0mm | 0. 8mm-1.2mm

Question 31

Chamfer width

Answer 31

0. 5mm | 0. 4mm-0.7mm

Question 32

What should be the difference between the depth orientation depth, and the final prep depth?

Answer 32

0.2mm more shallow

Question 33

What considerations should be taken into effect

Answer 33

Biological considerations Mechanical considerations Esthetic consideration

Question 34

What biological considerations should be taken?

Answer 34

Prevent damage during tooth prep Considerations affecting future dental health Conservation of tooth structure

Question 35

What mechanical considerations should be taken?

Answer 35

Providing resistance form Providing retention form Preventing deformation fo teh prep

Question 36

What are the indications for a crown?

Answer 36

``` Extensive coronal destruction Short clinical crowns Endo treated Maximum retention and resistance are needed Correction of axial contours ```

Question 37

What are contraindications for a crown?

Answer 37

Wherever an intact buccal or lingual wall exists If less than maximum retention and resistance are needed If objectives can be met with a more conservative restoration

Question 38

Why does a crown have greater retention than more conservative restorations?

Answer 38

All axial surfaces of the tooth are included

Question 39

T/F - A crown has greater resistance than a partial coverage restoration on the same tooth

Answer 39

True

Question 40

T/F - A complete cast crown allows the operator to modify axial tooth contours and the occlusal surface

Answer 40

True

Question 41

What are the disadvantages of a crown?

Answer 41

Remmoves a large amount of tooth structure Can have adverse effects on tissue Display of metal Vitality testing is not feasible