Class 2 Preps

Question 1

What are initial caries?

Answer 1

entirely in enamel

E1
E2
D1?
ICDAS 1
ICDAS 2

Question 2

What are moderate caries?

Answer 2

lesion entering dentin

D1
D2
ICDAS 3
ICDAS 4

Question 3

What are advanced caries?

Answer 3

well into dentin, approaching pulp

D3
ICDAS 5
ICDAS 6

Question 4

What is the dentist’s goal for removing interproximal caries?

Answer 4

• Remove carious tooth structure
• Remove least amount of tooth structure possible
• Prepare the tooth in a way that resists fracture, retains restoration, and has conveience form

Question 5

What is the point of the reverse S curve on a class II amalgam prep?

Answer 5

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

Question 6

How much should the buccal contact be open around a class II amalgam box?

Answer 6

0.2-0.5 mm

Question 7

How much should the lingual contact be open around a class II amalgam box?

Answer 7

0.02-0.5 mm

Question 8

How much should the gingival contact be open?

Answer 8

0.5 mm

Question 9

What are indications for composite?

Answer 9

Esthetics
Light occlusal contacts
Smaller restorations
Isolation
Light occlusal contacts
Smaller restorations
Very large restorations
Conservative or Preventative restorations
Temperature sensitivity

Question 10

What are not indications for composite?

Answer 10

• mercury fear
• ALS and MS patients

Question 11

What are contraindications to composite?

Answer 11

• heavy occlusal forces
• occlusal contacts on composite
• restorations extend to root surface
• deep subgingival margins
• diet
• poor oral hygiene
• unable to isolate

Question 12

Why does composite fail?

Answer 12

• 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

Question 13

What are the advantages of composite?

Answer 13

• Esthetic
• Conserves tooth structure
• Bonding; Reduced microleakage and recurrent decay and 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!!

Question 14

What are the disadvantages of composite?

Answer 14

• 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

Question 15

What is not necessary on a class II composite prep versus an amalgam one?

Answer 15

reverse S curve

Question 16

What is the pulpal floor depth of a class II composite prep on a molar?

Answer 16

2.0 mm

Question 17

What is the axial wall depth of a class II composite prep on a molar?

Answer 17

1.0 mm