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Operative > Class 2 Preparations > Flashcards

Class 2 Preparations Flashcards

1
Q

Initial Caries-

A

entirely in enamel

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2
Q

Moderate Caries-

A

lesion entering dentin

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3
Q

Advanced Caries-

A

well into dentin, approaching pulp

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4
Q

Root Caries-

A

lesion entering dentin

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5
Q

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Interproximal Caries
Dentist’s goal:

A
  • Remove carious tooth structure
  • Remove least amount of tooth structure possible
  • Prepare the tooth in a way that
  • RESISTS fracture
    • Restorative material and tooth
    • =RESISTANCE form
  • RETAINS the restoration
    • = RETENTION form
  • Is possible clinically without detriment to patient or dentriment
    • = CONVENIENCE form
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6
Q

Reverse S Curve (6)

A
  • Shape in outline form, nearly always on buccal side of preparation
  • Creates smoothly rounded form
  • Improves resistance to amalgam fracture
  • Keeps narrowest part of preparation away from axiopulpal line angle
  • Improves resistance to amalgam fracture
  • Allows preparation to break contact while allowing the buccal wall to meet the tooth surface at a 90 ̊ exit angle
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7
Q

Buccal Contact is Open

A

0.2–0.5 mm.

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8
Q

Gingival Contact

is Open at Least

A

0.5 mm

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9
Q

Gingival Contact is Open at Least 0.5 mm

This ensures:

A

the etched,
caries-susceptible area below the
contact area is clear

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10
Q

Lingual Contact is Open

A

.02–0.5 mm.

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11
Q

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Class II Amalgam Preparation Steps (10)

A

Step 1: Complete a Class I Amalgam Preparation
Step 2: Widen the dovetail faciolingually and thin the
marginal ridge to about 0.5-0.8 mm mesiodistally.
Step 3: Ditch for the Box
Step 4: Break through the thin enamel wall
Step 5: Remove Undermined Enamel Hooks
Step 6: Smooth the Gingival Floor
Step 7: Bevel the Axiopulpal Line Angle
Step 8: Remove Undermined Enamel from the Gingival Margin
Step 9: Smooth Walls, Perfect Outline, and Finish the Prep.
Step 10: Place Retention Grooves

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12
Q

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Step 2: Widen the dovetail faciolingually and thin the
marginal ridge to about 0.5-0.8 mm mesiodistally. (2)

A

Marginal Ridge Thinned
To .5-.8 mm. mesiodistally.
Dovetail widened.

Visualize the outline form
of the final prep. that you are
developing as you do this step.

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13
Q

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Step 3: Ditch for the Box

A

Use a 169 bur approaching parallel to the long axis of the tooth to ditch for the box. Move the
bur in a pendulum motion so the bucco-lingual dimension of the gingival floor is wider than the
occlusal width of the box. Walls should converge 3 ̊-4 ̊each.

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14
Q

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Step 4: Break through the thin enamel wall

A

Use the 169 bur and hand instruments to break through the thin shell of enamel that remains.
The round profile of the bur will have left “hooks” of undermined enamel on the buccal and
lingual margins that must be removed.

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15
Q

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Step 5: Remove Undermined Enamel Hooks (2)

A 
Use the enamel hatchet,with the
wide, flat side of the blade held
PERPENDICULAR to the surface of 
the tooth to remove the “hooks”
of undermined enamel

The preparation after removal
of undermined enamel

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16
Q

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Step 6: Smooth the Gingival Floor
Option A: Use of 56 or 57 bur (3)

A

• The 56 or 57 straight fissure burs have broad, flat ends, and are useful for smoothing the floor of a box.
• These burs also have sharp edges thatwill leave sharp internal line angles which must be rounded.
• Enamel rods are inclined gingivally. Remaining undermined enamel on
the gingival margin will need to be trimmed away with a hand instrument.

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17
Q

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Step 6: Smoothing the Gingival Floor
Option B: Use a 245 bur (3)

A

• The 245 bur has slightly rounded edges, naturally leaving more roundness at the buccal-gingival and
lingual-gingival internal line angles.
• It’send isn’t a large as that of a 56 or 57, making it more difficult for smoothing the gingival floor.
• Again, a hand Instrument will be needed to remove undermined enamel.

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18
Q

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Step 7: Bevel the Axiopulpal Line Angle (2)

A

• Use the flat end of a 56 or 57 straight fissure
bur to put a 45 ̊ bevel on the axiopulpal line
angle.
• By approaching through the open portion of
the box and using the flat end of a bur, you
are less likely to nick surrounding tooth
structure (vs. using the side of a 169 or a
7902 flame bur)

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19
Q

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Step 8: Remove Undermined Enamel from the Gingival
Margin

A

Use the gingival margin trimmer in a scraping motion to

Remove undermined enamel from the gingival margin.

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20
Q

Purpose of Retention Grooves:

A

To retain the amalgam segment that fills the

box against INTERPROXIMAL displacement

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21
Q

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Step 10, cont’d: Retention Grooves (4)

A

a. (We are going to place a buccal axial retention groove as an example) Place flutes of the 169 bur
right against the buccal axialline angle of the box.
b. Tip the bur mesially and lingually. Only the tip of the bur touches the tooth in the buccal-gingival-
axial point angle.
c. Activate the bur and push in a disto-buccal direction, bisecting the line angle on a conservative prep.
The groove should be JUST INSIDE THE D.-E. JUNCTION, ENTIRELY IN DENTIN.
d. Do a comparable groove in the lingual-axial line angle.
The grooves do NOT go into the gingival floor.

22
Q

The groove is at its deepest at

the —.

A

gingival

• It is the depth of the end of the 169 bur
(0.5 mm.)
• The groove fades out to nothing as it
reaches the axiopulpal line angle (or the
occlusal D.-E. junction). It does NOT go
into the gingival floor

23
Q

Path of Entry: Exception

• Mandibular First Premolar (3)

A
  • The Long Axis of the crown of this tooth tilts lingually relative to Long Axis of the tooth root
  • A Class I or II preparation should enter parallel to the long axis of the tooth CROWN
    • this will preserve strength in the small lingual cusp
24
Q

Composite preparations are different from amalgam

preparations BECAUSE

A

THE MATERIALS ARE DIFFERENT

25
Q

composite restoration vs amalgam (3)

A

Preparations can be more conservative
Bonding capability of composite may strengthen supporting tooth structure
Composite is a good insulator

26
Q

Indications for Composite (4)

A

Esthetics
Light occlusal contacts
Smaller restorations
Isolation

27
Q

Esthetics (3)

A

◦ Anterior teeth
◦ Facial of premolars or first molar
◦ Patient desire

28
Q

Light occlusal contacts (2)

A

◦ Must have centric TOOTH SUPPORTED occlusion on marginal ridges and cusp tips
◦ Composite does not support occlusion

29
Q

Smaller restorations (5)

A 
◦ Class I occlusal, buccal pits, lingual pits
  ◦ Excellent prognosis
  ◦ Low stress areas
  ◦ Premolars > molars
◦ Small Class II restorations
30
Q

◦ Keep margins in

A

enamel

◦ Don’t forget to bevel enamel

31
Q

= MINIMIZE (2)

A

microleakage and post-operative sensitivity

32
Q

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Possible Indications for Composite
Special situations

A

◦ Crown foundation
◦ “Buildup” material
◦ Very large restorations
◦ To strengthen remaining weakened tooth structure
◦ Economic reasons or provisionally
◦ Conservative or Preventative restorations
◦ Can preserve tooth structure
◦ May be in conjunction with sealants
◦ Temperature sensitivity with metal restorations
◦ Cross reaction between nickel allergy and silver
◦ RARE and controversial

33
Q

NOT AN INDICATION FOR COMPOSITE (2)

A

Mercury fear
◦ Educate your patients
◦ Respect their autonomy

ALS and MS patients
◦ Amyotrophic Lateral Sclerosis and Multiple Sclerosis
◦ Has not been conclusively shown to contribute to these conditions
◦ Multiple Sclerosis Society does not recommend removal of amalgam fillings to patients with MS.

34
Q

Contraindications to Composite (7)

A

Heavy occlusal forces
Occlusal contacts entirely on composite
Restorations extending to root surface
Deep subgingival margins

Diet
◦ Highly acidic oral environment
◦ High alcohol consumption
Poor Oral Hygiene
Unable to isolate
35
Q

Why does composite fail? (5)

A

Dentin tubules
◦ More tubules as preparations get deeper= MORE FLUID
Adhesives
◦ Water based adhesives undergo phase separation
Etch
◦ Operator error- easier to etch dentin too long
◦ Collapse tubules
Orientation of enamel vs. dentin
Polymerization shrinkage

36
Q

Advantages of Composite (6)

A 
Esthetic
Conserves tooth structure
Bonding
◦ Reduced microleakage and recurrent decay
◦ Increased retention
No metal
◦ No mercury arguments from patients
◦ No corrosion
◦ No galvanic shock
Can be economical
◦ Vs. crowns and inlays/onlays
Preparation may be more forgiving
◦ RESTORATION IS NOT!!!
37
Q

Disadvantages of Composite (8)

A 
Low modulus of elasticity
Porous
More technique sensitive placement
More time-consuming placement
Microleakage
May stick to instrument, resulting in voids
Can’t place in bulk
Expensive compared to amalgam
38
Q

COMPOSITE PREPARATION/RESTORATION (4)

A 
Remove defect
Prepare tooth structure for adhesive
Treat prepared tooth structure with adhesive
Place composite
◦ Contour, finish, polish
39
Q

COMPOSITE PREPARATION

Clean tooth

A

◦ Pumice and water mixture

40
Q

skipped
COMPOSITE PREPARATION
Proximal outline form (3)

A 
◦ Must break gingival margin
   ◦ CARIES must be removed
     ◦ Occur just below contact
   ◦ Matrix band must fit passively
◦ Keep margins in enamel when possible
◦ Only remove carious tooth structure
41
Q

COMPOSITE PREPARATION

Proximal outline form: break…

A

◦ Break lingual contact

You will learn to break buccal contact AND to leave buccal contact intact

42
Q

COMPOSITE PREPARATION
s curve?
bevel?
hooks?

A 
Reverse S curve not necessary
◦ Flare buccal wall instead
Bevel proximal lingual wall
Same as amalgam:
◦ NO HOOKS
43
Q

COMPOSITE PREPARATION

Pulpal floor depth

A

◦ 1.5mm

◦ Ideally, no greater than 2.5mm

44
Q

COMPOSITE PREPARATION

Axial Wall Depth

A

◦ 1.0mm

45
Q

COMPOSITE PREPARATION

BEVELS (3)

A

◦ Lingual wall bevel
◦ Gingival bevel
◦ Axial-pulpal line angle bevel

46
Q 
COMPOSITE PREPARATION
NO BEVEL (2)
A

if in the dentin/cementum

47
Q 
COMPOSITE PREPARATION
NO ---
Dovetail ---
Slightly --- or parallel occlusal walls
No adjacent --- ---
A

HOOKS
diverged
converged
tooth damage

48
Q 
COMPOSITE PREPARATION
Finish Preparation (2)
A

◦ Use flame shaped diamond bur

◦ Use hatchet on proximal walls

49
Q

Can keep composite preparations

A

SMALL

◦ Remove all caries, but keep preparation conservative

50
Q

INSPECT PREP BEFORE RESTORING (2)

A

◦ Free of debris, moisture

◦ Blood and saliva

Operative (11 decks)

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