Cavity Preps

Question 1

In what cases do we need to end with diverging walls in class I?

Answer 1

When needing to remove enamel undercuts (unsupported enamel)

Question 2

Where should the pulpal floor be?

Answer 2

Always on Dentin, ideally just below the DEJ

Pulpal floor is flat or follows the rise and fall of occlusal surface

Question 3

What is the ideal orientation of enamel rods in a prep?

Answer 3

full length of rods, supported by shorter rods both attached to sound dentin

Question 4

In what cases should we reduce the cusp tips?

Answer 4

when caries covers 1/2 distance from primary groove to cusp tip
when caries covers 2/3 from an adjacent primary groove to the cusp tip

Question 5

What is a dovetail?

Answer 5

= a primary retention feature (extension for retention)

Question 6

What is the guideline for formation of the proximal box in class II?

Answer 6

extend gingivally past either caries or occlussal contact (whichever is deeper)

2/3 expense of enamel, 1/3 expense dentin

Question 7

What form does the axial wall of the proximal box has?

Answer 7

faciolingual contour of proximal tooth surface

Question 8

In which cases are cusp reductions usually required in class II?

Answer 8

DB cusp of maxillary M2

D cusp of mandibular M1

Question 9

When is Adjoining restorations permissible?

Answer 9

when the remaining has adequate resistance and retention forms

Question 10

What do we need to consider for class II on mandibular P1?

Answer 10

• location of pulp chamber
• size of lingual cusp
• entry of bur should be tilted at bisector of angle between long axis of tooth and line perpendicular to faciolingual cusp tips

Question 11

Where are retention grooves placed in the class II proximal box?

Answer 11

axiolingual and axiofacial line angles always in bisector

Question 12

Where are retention grooves placed in the lingual prep of 2 surface class I?

Answer 12

distoxaial and mesioaxial line angles

The depth of retention grooves is usually the size of half the diameter of the bur used (0.25 - 0.5 mm deep)

Question 13

What secondary retention features do we place for class V?

Answer 13

Retention grooves: occlusoaxial and gingivoaxial

Retention coves:
in each axial point angle

Question 14

If the facial wall is divergent what secondary retention feature is added?

Answer 14

A retention undercut in the faciopulpal line angle

Question 15

Which area do carries grow faster in?

Answer 15

Pit and fissure

Question 16

When you need to prepare retention grooves,
these should be:

a. On the DEJ.
b. 0.2 mm inside dentin.
c. 0.5 mm inside dentin.
d. On the deepest part of the preparation.

Answer 16

c. 0.5 mm inside dentin

Question 17

Which of the following tooth preparations
require more often secondary retention form?

a. Class I.
b. Two surface Class I.
c. Class II.
d. Class V.

Answer 17

d. Class V

Question 18

Complex amalgam indications:

Answer 18

• Cusp fracture, severe caries lesion, replacement of old restoration
• When 1 or more cusps need to be covered
• When additional retention and R forms needed
• Definitive restorations
• As interim (temporary) restorations
• In teeth with questionable endodontic or periodontal prognosis
• Foundations and core build ups

Question 19

Complex amalgam contraindications:

Answer 19

• When a proper anatomic and functional form cannot be achieved with a direct restorative material
• When the tooth is aesthetically important

Question 20

What are the 3 types of pins?

Answer 20

• Cemented pins
• Friction-locked
• Self-threading pins

Question 21

What are the precautions if pulpal perforation occurs with wrong pinhole placement?

Answer 21

• place Ca(OH)2
• prepare another pinhole 1.5 mm away
• endo therapy

Question 22

What are the precautions if perforation of external tooth surface occurs with wrong pinhole placement?

Answer 22

• careful probing
• radiographic examination
• occlusal or apical to gingival attachment

Question 23

Perforation occlusal to gingival attachment treatment options:

Answer 23

• cut the pin (no further treatment)
• remove the pin, enlarge pinhole, restore w/ AMG
• indirect restoration

Question 24

Perforation apical to gingival attachment treatment options:

Answer 24

• osteoctomy, enlarge pinhole, restore w/ AMG

- crown lengthening, place margin of a cast restoration to gingival perforation

Question 25

When conventional retention features are not

available, what other additional features may be needed?

Answer 25

• pins

- slots

Question 26

When would you bevel/not bevel the facial surface of anterior teeth?

Answer 26

not bevel if there is unsupported enamel

Question 27

When would you bevel/not bevel the lingual surface of anterior teeth?

Answer 27

bevel if large restoration

not bevel if it is a small restoration

Question 28

For complex AMG what should be also used

in the remaining vertical walls?

Answer 28

Coves and retention grooves

Question 29

What is a slot?

Answer 29

= is a horizontal retention groove in dentin, placed in the gingival floor of a preparation
-When there is no vertical walls, slots may be needed for
retention

Question 30

When do we use pins?

Answer 30

whenever adequate resistance and
retention forms are not able to be established with
grooves, slots or coves

Question 31

What are the cautions indicated when using pins?

Answer 31

– Craze lines or fractures may be created

– Internal stresses in dentin are developed

Question 32

What are the steps for AMG application?

Answer 32

1. prep
2. trituration
3. condensation
4. precarve burnishing
5. carving
6. adjust occlusion
7. postcarve burnishing
8. finishing and polishing

Question 33

Where can we place secondary retention grooves?

Answer 33

class III, class V and complex amalgam restorations

Question 34

How is the rotary instruments alignment for facial or lingual caries?

Answer 34

Perpendicular to the external surface of the tooth

Question 35

What is an Outline form?

Answer 35

=the overall outline of the preparation

Question 36

What happens if you hit an adjacent tooth while doing the prep on another tooth?

Answer 36

• if tiny fragment you can polish it

- if big then do another restoration

Question 37

What are the advantages of lingual approach?

Answer 37

• The facial enamel is conserved for enhanced esthetics -Shade matching of the composite is less critical
• Discoloration or deterioration of the restoration is less visible