Fixed I - Complete Metal Crown Preparation

What is an artificial crown?

restoration that restores missing tooth structure of 3 or more axial surfaces and the occlusal surface or incisal edge of a tooth with a material such as cast metal alloy, ceramics, resin, or combination of materials

True/False: in a complete crown, the whole tooth is prepped and covered with a crown

True

True/False: in a partial crown, the whole tooth is prepped and covered with a crown

False

How many surfaces does a pinledge onlay cover?

one

What are ways to manufacture a crown?

casting (lost-wax technique), CAD-CAM (additive and subtractive)

What are indications for a full crown?

extensive destruction, endodontic treatment, size of existing restoration

All of the following are indications for a full crown EXCEPT one. Which one is the exception?

A) extensive destruction

B) endodontic treatment

C) large existing restoration

D) high esthetics

E) contour modification

F) occlusal plane change

D) high esthetics

All of the following are contraindications for a complete crown EXCEPT one. Which one is the exception?

A) more conservative technique is possible

B) removable partial denture is planned

C) extensive destruction

D) high esthetics

C) extensive destruction

What are advantages of complete crowns?

1) greater retention

2) greater resistance

3) extensive tooth removal

4) form modification

A) 1, 2, 3

B) 2, 3, 4

C) 1, 2, 4

D) 1, 2, 3, 4

C) 1, 2, 4

What are disadvantages of a complete crown?

adverse tissue effects, removal of hard tissue, electric pulp testing, esthetics

Compared to MOD onlay, 3/4 crown and 7/8 crown, a complete crown has ____ retention.

A) lesser

B) the same amount of

C) greater

C) greater

True/False: resistance increases as you approach parallel

True

True/False: a smaller prep compared to a taller prep has better resistance

False

What is an ideal height of a prep for all teeth except molars?

A) 2 mm

B) 3 mm

C) 3.5 mm

D) 4 mm

B) 3 mm

What is an ideal height of a prep for molars?

A) 2 mm

B) 3 mm

C) 3.5-4 mm

D) 5 mm

C) 3.5-4 mm

For a metal crown, occlusal reduction on a nonholding/nonfunctional cusp should be

A) 0.5 mm

B) 1.0 mm

C) 1.5 mm

D) 2.0 mm

B) 1.0 mm

For a metal crown, occlusal reduction on a holding/functional cusp should be

A) 0.5 mm

B) 1.0 mm

C) 1.5 mm

D) 2.0 mm

C) 1.5 mm

Place these steps in the correct order:

1) occlusal reduction

2) depth grooves

3) axial reduction

4) depth grooves for axial reduction

5) finishing the preparation

6) margin placement

A) 1, 2, 3, 4, 5, 6

B) 2, 3, 4, 6, 5, 1

C) 2, 1, 4, 3, 6, 5

D) 2, 1, 4, 5, 3, 6

C) 2, 1, 4, 3, 6, 5

The functional bevel should be ___ degrees to the long axis of the tooth

A) 30

B) 35

C) 40

D) 45

D) 45

What is the best way to protect adjacent teeth?

A) matrix band

B) fender wedge

C) thin lip of enamel

D) retraction cord

C) thin lip of enamel

The mesiodistal taper or convergence should be ___ degrees

A) 1-3

B) 3-5

C) 6-10

D) 10-12

C) 6-10

True/False: the bur should be held perpendicular to the long axis of the tooth

False

True/False: sharp cusp tips after prepping a tooth are acceptable

False

A chamfer margin should ideally be ____ mm

in width

A) 0.3 mm

B) 0.5 mm

C) 0.7 mm

D) 0.9 mm

B) 0.5 mm

True/False: a chamfer margin should be smooth and continuous

True

Proximal clearance between adjacent teeth should at least be ____ mm

A) 0.2 mm

B) 0.4 mm

C) 0.6 mm

C) 0.6 mm

From the mesial view when evaluating the prep, the lingual wall should be ___ degrees to the occlusal surface

A) 45

B) 60

C) 90

D) 100

C) 90

From the mesial view when evaluating your prep, the buccolingual convergence should be ____ degrees

A) 1-3

B) 2-5

C) 6-10

D) 10-12

C) 6-10

True/False: you should be able to see all margins and axial walls of your prep from the occlusal view

True

If you see too much of your axial wall of your prep from the occlusal view, that means your prep is

A) perfect

B) undercut

C) overcut

C) overcut

If you see too little of your axial wall (as in, not at all) of your prep from the occlusal view, that means your prep is

A) perfect

B) undercut

C) overcut

B) undercut

True/False: the surface of your prep should be polished smooth

False

True/False: you want a lingual wall of your prep to tip buccally at a 15 degree angle

False (too much tip)

The recommended margin for a complete cast crown is

A) bevel

B) chamfer

C) shoulder

D) shoulder-bevel

E) all of the above

B) chamfer

True/False: a complete cast crown preparation will have significantly more retention when the occlusocervical height of the preparation increases

True

True/False: Assuming on other variables in a complete cast crown preparation, premolar teeth have a higher resistance form than do molar teeth

True

During fixed prosthodontic treatment, an irreversible pulpitis can result as a consequence of which of the following?

A) prior carious insult

B) excessive preparation taper

C) preparation trauma

D) all of the above

E) none of the above

D) all of the above

True/False: historically, textbooks that discuss the principles of tooth prep have recommended teeth be prepared with 2-6 degrees of total occlusal convergence

True

What is clearance?

A) amount of space between completed prep and opposing tooth

B) amount of tooth structure that is removed

A) amount of space between completed prep and opposing tooth

What is reduction?

A) amount of space between completed prep and opposing tooth

B) amount of tooth structure that is removed

B) amount of tooth structure that is removed