Designs for Class I Lesions Flashcards

1
Q

Advantages and disadvantages of Sealants/Glass ionomers

A

Adv. - Conservative, Low cost

Disadv. - Poor longevity

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2
Q

Advantages and disadvantages of PRR/Composite

A

Adv. - Conservative, Aesthetic

Disadv. - Cost (25% higher), Technique sensitive

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3
Q

Advantages and disadvantages of Amalgam

A

Adv. - Cost, Longevity

Disadv. - More tooth removed, Mercury alloy

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4
Q

Advantages and disadvantages of Gold

A

Adv. - Most durable

Disadv. - Highest cost, Fabrication time

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5
Q

What 7 factors affect our treatment recommendations?

A
  1. Stress on the tooth
  2. Aesthetics
  3. Pt’s out of pocket expenses
  4. Size of lesion
  5. Pt’s CRA
  6. Amount of enamel remaining
  7. Ability to isolate tooth
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6
Q

3 main indications for Class I amalgam restorations

A
  1. Pits and fissures of occlusal surfaces of posterior teeth (Premolars & Molars)
  2. Pits in the occlusal 2/3 of facial & lingual surfaces of molars
  3. Lingual pits of maxillary incisors in the top 2/3 of tooth
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7
Q

Define Cavo-surface

A

The junction between the preparation and uncut enamel

- The outline of the preparation

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8
Q

T or F,

  1. Avoid making the marginal ridge too thick
  2. Avoid cutting into the triangular ridges
A
  1. False, too thin

2. True

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9
Q

T or F,

  1. Avoid having the cave-surface end at opposing contacts
  2. Keep the cave-surface sharp and well-defined
A
  1. True

2. True

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10
Q

T or F,

  1. The outline at the proximal should be perpendicular to the marginal ridge
  2. Keep the marginal ridge as thin as possible
A
  1. False, Parellel

2. False, Thick as possible

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11
Q

Which two groups of teeth should you beware to not cut across the transverse/oblique ridge of when making separate preparations?

A
  1. Lower first premolars

2. Upper permanent molars

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12
Q

What are the preparation guidelines for the pupal floor?

A
  1. Should be smooth

2. Should be flat or slightly rounded

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13
Q

What is the minimum depth for the pulpal floor?

A
  • Need a minimum of 1.5 mm depth starting from the central groove of amalgam carving.
  • Facial and lingual walls at the cave-surface may be deeper closer to 2.0 mm
  • *Range of 1.5 to 2.0 mm
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14
Q

May enamel islands remain on the pulpal floor of a prep?

A

They may remain as long as we are at the minimum depth

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15
Q

If there is decay deeper than the minimum depth, do you remove it first or last?

A

Last, to avoid spreading decay into the pulpal cavity if there is a pulp breach

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16
Q

In what teeth will the pulpal floor be slanted so as to make it parallel to the plane between the facial and lingual cusps?

A

Lower first premolars

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17
Q

What is the minimum measurement for the isthmus?

A

Minimally 1.0 mm

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18
Q

T or F, Isthmus follow the decay even if it is not centered in the tooth

A

False, Isthmus follows the decay but also should be centered in the tooth when possible

19
Q

All internal line angles need to be what shape?

A

Rounded

20
Q

Facial and Lingual walls should be slightly what shape?

A

Convergent

21
Q

T or F, It is critical to have supported enamel rods on facial and lingual walls?

A

True

- Do not overture or over converge

22
Q

T or F, A smaller isthmus allows for a greater convergence

A

True

23
Q

T or F, There is no convergence on the medial or distal wall

A

True

24
Q

What should the medial and distal walls look like in a Class I preparation?

A

Are straight or even slightly divergent. This prevents unsupported enamel. Convergent proximal walls create unsupported enamel.

25
Q

Should the proximal walls be more or less divergent the thinner the marginal ridge is?

A

More divergent

- Because the enamel rods diverge more the close we get to the proximal surface of the tooth.

26
Q

Maxillary Bicuspids: What does the outline follow?

A

The general direction of the central groove

27
Q

Maxillary Bicuspids: T or F, The mesial & distal pits don’t need to be symmetrical

A

False, They do need to be symmetrical

28
Q

Maxillary Bicuspids: What is the relationship between the medial and distal marginal ridges and the dovetails?

A

They should be parallel to the dovetails

29
Q

Maxillary Bicuspids: There is one thing very important to remember with these teeth regarding a strong medial concavity. What is it?

A

Because it has a strong medial concavity, the medial wall may need to be slightly more divergent

30
Q

Maxillary Molars: 2 important points

A
  1. Do not cut through the oblique ridge if not necessary.

2. The walls adjacent to the oblique ridge are parallel to the oblique ridge

31
Q

Maxillary Incisors: How are the walls cut?

A

Perpendicular to the surface of the tooth

32
Q

Mandibular Molars: One important thing to remember regarding the central groove

A

The center of the preparation is slightly facial to the central groove of the tooth.

33
Q

Mandibular molars B pit: What is the minimum depth and how are the walls formed?

A

Minimum depth: to the DEJ

Walls are convergent to retain the amalgam

34
Q

Mandibular Second premolar: There are 3 types of outlines, what are they?

A

Described as U, Y, or H type

35
Q

Once the dentin is involved, what type of restorative materials are needed?

A

Composite

36
Q

For composite preparations, what dictates the outline and depth?

A

Caries dictates the outline and depth

37
Q

What is the minimum depth requirement and where is that required?

A

Only in areas of opposing contact is there a minimum depth requirement of 1.5 mm

38
Q

Does the pulpal floor need to be smooth and flat in composite preparations?

A

No, it may be irregular but have no sharp internal line angles

39
Q

What are the walls supposed to be like in composite preparations?

A

Walls may be slightly convergent or straight

40
Q

Class I composite restorations not in direct occlusal contact may have an external cave-surface bevel of what?

A

1 mm

41
Q

What are the guidelines for proximal walls in composite restorations?

A

Do not require divergence and may be straight

**A small amount of undermined enamel is acceptable

42
Q

What burs can be used for Class I restorations?

A
34 diamond 
245 carbide
330 pear carbide
1/2 round 
330 diamond
132F diamond
43
Q

Outline the steps for an amalgam preparation

A
  1. # 34 diamond bur and cut rough outline smaller than anticipated finished outline
  2. Smooth and deepen your pulpal floor close to, but just short of ideal depth
  3. # 330 diamond bur to finish preparation
  4. If there is deep decay, now is the time to use slow speed handpick with round burs to remove small areas of deeper decay
  5. Wash and cleanse your preparation for placing amalgam