Designs for Class I Lesions

Question 1

Advantages and disadvantages of Sealants/Glass ionomers

Answer 1

Adv. - Conservative, Low cost

Disadv. - Poor longevity

Question 2

Advantages and disadvantages of PRR/Composite

Answer 2

Adv. - Conservative, Aesthetic

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

Question 3

Advantages and disadvantages of Amalgam

Answer 3

Adv. - Cost, Longevity

Disadv. - More tooth removed, Mercury alloy

Question 4

Advantages and disadvantages of Gold

Answer 4

Adv. - Most durable

Disadv. - Highest cost, Fabrication time

Question 5

What 7 factors affect our treatment recommendations?

Answer 5

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

Question 6

3 main indications for Class I amalgam restorations

Answer 6

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

Question 7

Define Cavo-surface

Answer 7

The junction between the preparation and uncut enamel

- The outline of the preparation

Question 8

T or F,

1. Avoid making the marginal ridge too thick
2. Avoid cutting into the triangular ridges

Answer 8

1. False, too thin

2. True

Question 9

T or F,

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

Answer 9

1. True

2. True

Question 10

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

Answer 10

1. False, Parellel

2. False, Thick as possible

Question 11

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

Answer 11

1. Lower first premolars

2. Upper permanent molars

Question 12

What are the preparation guidelines for the pupal floor?

Answer 12

1. Should be smooth

2. Should be flat or slightly rounded

Question 13

What is the minimum depth for the pulpal floor?

Answer 13

• 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

Question 14

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

Answer 14

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

Question 15

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

Answer 15

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

Question 16

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

Answer 16

Lower first premolars

Question 17

What is the minimum measurement for the isthmus?

Answer 17

Minimally 1.0 mm

Question 18

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

Answer 18

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

Question 19

All internal line angles need to be what shape?

Answer 19

Rounded

Question 20

Facial and Lingual walls should be slightly what shape?

Answer 20

Convergent

Question 21

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

Answer 21

True

- Do not overture or over converge

Question 22

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

Answer 22

True

Question 23

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

Answer 23

True

Question 24

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

Answer 24

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

Question 25

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

Answer 25

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

Question 26

Maxillary Bicuspids: What does the outline follow?

Answer 26

The general direction of the central groove

Question 27

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

Answer 27

False, They do need to be symmetrical

Question 28

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

Answer 28

They should be parallel to the dovetails

Question 29

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

Answer 29

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

Question 30

Maxillary Molars: 2 important points

Answer 30

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

Question 31

Maxillary Incisors: How are the walls cut?

Answer 31

Perpendicular to the surface of the tooth

Question 32

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

Answer 32

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

Question 33

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

Answer 33

Minimum depth: to the DEJ | Walls are convergent to retain the amalgam

Question 34

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

Answer 34

Described as U, Y, or H type

Question 35

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

Answer 35

Composite

Question 36

For composite preparations, what dictates the outline and depth?

Answer 36

Caries dictates the outline and depth

Question 37

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

Answer 37

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

Question 38

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

Answer 38

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

Question 39

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

Answer 39

Walls may be slightly convergent or straight

Question 40

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

Answer 40

1 mm

Question 41

What are the guidelines for proximal walls in composite restorations?

Answer 41

Do not require divergence and may be straight | **A small amount of undermined enamel is acceptable

Question 42

What burs can be used for Class I restorations?

Answer 42

``` 34 diamond 245 carbide 330 pear carbide 1/2 round 330 diamond 132F diamond ```

Question 43

Outline the steps for an amalgam preparation

Answer 43

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