Cavity Preps Flashcards

1
Q

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

A

When needing to remove enamel undercuts (unsupported enamel)

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2
Q

Where should the pulpal floor be?

A

Always on Dentin, ideally just below the DEJ

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

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3
Q

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

A

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

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4
Q

In what cases should we reduce the cusp tips?

A

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

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5
Q

What is a dovetail?

A

= a primary retention feature (extension for retention)

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6
Q

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

A

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

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

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7
Q

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

A

faciolingual contour of proximal tooth surface

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8
Q

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

A

DB cusp of maxillary M2

D cusp of mandibular M1

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9
Q

When is Adjoining restorations permissible?

A

when the remaining has adequate resistance and retention forms

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10
Q

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

A
  • 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
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11
Q

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

A

axiolingual and axiofacial line angles always in bisector

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12
Q

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

A

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)

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13
Q

What secondary retention features do we place for class V?

A

Retention grooves: occlusoaxial and gingivoaxial

Retention coves:
in each axial point angle

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14
Q

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

A

A retention undercut in the faciopulpal line angle

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15
Q

Which area do carries grow faster in?

A

Pit and fissure

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16
Q

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.

A

c. 0.5 mm inside dentin

17
Q

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.

A

d. Class V

18
Q

Complex amalgam indications:

A
  • 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
19
Q

Complex amalgam contraindications:

A
  • When a proper anatomic and functional form cannot be achieved with a direct restorative material
  • When the tooth is aesthetically important
20
Q

What are the 3 types of pins?

A
  • Cemented pins
  • Friction-locked
  • Self-threading pins
21
Q

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

A
  • place Ca(OH)2
  • prepare another pinhole 1.5 mm away
  • endo therapy
22
Q

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

A
  • careful probing
  • radiographic examination
  • occlusal or apical to gingival attachment
23
Q

Perforation occlusal to gingival attachment treatment options:

A
  • cut the pin (no further treatment)
  • remove the pin, enlarge pinhole, restore w/ AMG
  • indirect restoration
24
Q

Perforation apical to gingival attachment treatment options:

A
  • osteoctomy, enlarge pinhole, restore w/ AMG

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

25
Q

When conventional retention features are not

available, what other additional features may be needed?

A
  • pins

- slots

26
Q

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

A

not bevel if there is unsupported enamel

27
Q

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

A

bevel if large restoration

not bevel if it is a small restoration

28
Q

For complex AMG what should be also used

in the remaining vertical walls?

A

Coves and retention grooves

29
Q

What is a slot?

A

= 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

30
Q

When do we use pins?

A

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

31
Q

What are the cautions indicated when using pins?

A

– Craze lines or fractures may be created

– Internal stresses in dentin are developed

32
Q

What are the steps for AMG application?

A
  1. prep
  2. trituration
  3. condensation
  4. precarve burnishing
  5. carving
  6. adjust occlusion
  7. postcarve burnishing
  8. finishing and polishing
33
Q

Where can we place secondary retention grooves?

A

class III, class V and complex amalgam restorations

34
Q

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

A

Perpendicular to the external surface of the tooth

35
Q

What is an Outline form?

A

=the overall outline of the preparation

36
Q

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

A
  • if tiny fragment you can polish it

- if big then do another restoration

37
Q

What are the advantages of lingual approach?

A
  • 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