Chapters 1-5

Question 1

The final shape (form of the tooth, produced using instrumentation) to receive a restoration

Answer 1

preparation

Question 2

Extracoronal preparation involving the entire clinical crown

Answer 2

complete veneer crown preparation

Question 3

A cast-gold extracoronal restoration which covers the clinical crown

Answer 3

complete veneer crown (CVC)

Question 4

The imaginary line along which a casting is moved when it is separated from its single crowns the path of withdrawal should be nearly coincident with the tooths long axis, which can be formed by opposing axial surfaces in third of the tooth

Answer 4

Path of withdrawal (POW)

Question 5

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

Answer 5

axial wall

Question 6

the angle or taper formed by diametrically opposed axial walls

Answer 6

convergence angle

Question 7

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

Answer 7

chamfer

Question 8

The junction of the prepared (cut) to unprepared (uncut) tooth structure. This is an external line angle.

Answer 8

cavo-surface line angle

Question 9

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

Answer 9

depth orientation grooves

Question 10

A wide bevel placed on the functional cusps (buccal for mandibular and lingual for maxillary)

Answer 10

Functional cusp bevel

Question 11

A crown preparation is said to be undercut if a wax pattern cannot be withdrawn from its die without distortion. What are two things that may cause this?

Answer 11

1.) a depression in the axial wall, cause, for example, by a carious lesion
2.) diametrically opposed axial walls that do not converge occlusally caused by improper angulation of the cutting instrument
(type 1 can usually be corrected with a base material while type 2 must be further reduced)

Question 12

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

Answer 12

occlusal clearance

Question 13

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

Answer 13

retention form

Question 14

The characteristics of a tooth prepartation which tends to prevent dislodgment of a seated restoration by forces directed in an apical or oblique direction. It works through the use of occlusal forces.

Answer 14

resistance form

Question 15

What are the advantages of CVCs?

Answer 15

1. high strength
2. longevity
3. high resistance to displacement
4. ability to modify axial contours and occlusion

Question 16

Disadvantages of CVCs?

Answer 16

1. display of metal
2. removal of tooth substance
3. vitality testing
4. margin close to gingival tissue

Question 17

Indications for CVCs

Answer 17

1. extensive destruction by caries or trauma
2. endodontically treated teeth
3. large existing restorations
4. maximum retention needed
5. recontouring of axial surfaces
6. correction of malinclination
7. correction of occlusal discrepancies
8. to provide contours suitable for a removable partial denture

Question 18

Contraindiction for CVCs

Answer 18

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

Question 19

Principles of tooth preps

Answer 19

1. conservation of tooth structure
2. marginal integrity of the restoration
3. retention and resistance
4. structural durability

Question 20

Excess reduction will occur if:

Answer 20

1. the tooth is prepared with excessive convergence angle (recommended 2 to 10 degrees)
2. the prep does not follow the anatomical features
3. the path of withdrawal diverges from the long axis of the tooth
4. and excessively wide margin
5. excessively gingival extension of the prep

Question 21

Inadequate marginal integrity will occur if:

Answer 21

1. the chamfer is too narrow to provide sufficient bulk of restorative material without over contouring (ideal is 0.5 mm
2. the cavo-surface line angle cannot easily be determined during lab procedures
3. the chamfer is rough or uneven
4. the preparation is undercut causing distortion of the wax pattern

Question 22

Causes of inadequate retention and resistance are:

Answer 22

1. excessive convergence angle (greater than 10 degrees)
2. inadequate height and surface area of the axial walls
3. insufficient surface area to resist tipping of the restoration

Question 23

Structural durability acceptable ranges

Answer 23

1. functional cusp 1.5 mm (1.3 mm-1.7 mm)
2. central groove 1.0 mm (0.8 mm- 1.2 mm)
3. non-functional cusp 1.0 mm (0.8 mm- 1.2 mm)
4. Chamfer width 0.5 mm (0.4 mm- 0.6 mm)

Question 24

The 242.6M and 243.6M diamond burs are ____ to produce a chamfer as the bur cuts into the tooth.

Answer 24

hemispherical (leave a 3-4 degree occlusal convergence)

Question 25

When cutting our silicon reduction guide, the guide should be cut from ____ to ____.

Answer 25

mid-buccal, mid-lingual

Question 26

Grooves are places ____ mm shallower than the intended tooth reduction to allow finishing and smoothing.

Answer 26

0.2 mm

Question 27

Interproximally, the prep must extend cervically to the contact area to provide a ___ mm clearance with the adjacent tooth.

Answer 27

0.5 mm