Class I & V Preparation Fundamentals

Question 1

Principles of tooth preparation for amalgam restorations include:

Answer 1

1. Visibility
2. Access
3. Moisture control

Question 2

When doing an amalgam restoration, have a means for ____ of the site.

Answer 2

isolation

Question 3

Modes of isolation include:

Answer 3

1. rubber dam (gold standard)
2. cotton rolls
3. retraction cord
4. isovac

Question 4

Principles: treatment of tooth structure-

All ____ must be removed from all margins

Answer 4

undermined enamel

Question 5

Enamel that is not supported by dentin underneath it:

Answer 5

undermined enamel

Question 6

____ must support all surface enamel

Answer 6

dentin

Question 7

Margins should be ____ at the cavosurface on all axial surfaces

Answer 7

90 degrees

Question 8

On the occlusal surface, margins may be ____ in some areas but must NEVER BE ____ anywhere on the tooth

Answer 8

slightly obtuse; never be acute

Question 9

What would occur if the margins at the cavosurface were acute?

Answer 9

enamel would break

Question 10

Ideal preparations are ____ to ____ into the dentin:

Answer 10

0.2mm-0.5mm

Question 11

Ideal preparations must be prepared through the:

Answer 11

ENTIRE enamel layer

Question 12

In a live patient, the depth of an ideal preparation into the dentin is determined by:

Answer 12

caries

Question 13

The traditional teaching about the outline form of an amalgam preparation states that the preparation must NOT terminate in:

Answer 13

the bottom of a FISSURED pit or groove

Question 14

On class II amalgams, contact is broken:

Answer 14

facially and lingually

Question 15

Preparations should encompass all carious and badly demineralized areas, this is called:

Answer 15

extension for prevention

Question 16

term that refers to what holds a restoration in a tooth:

Answer 16

retention form

Question 17

Does amalgam bond to tooth structure?

Answer 17

no

Question 18

Smaller amalgams are heading by ____ and/or _____ if no walls can converge

Answer 18

converging walls and/or retention grooves

Question 19

Elements in the design of a tooth preparation that will help both restoration and tooth resist fracturing:

Answer 19

resistance form

Question 20

Retaining as much tooth structure as possible makes the the tooth:

Answer 20

less likely to fracture

Question 21

Having some areas on the floor of a multi-surface preparation that are ___ to the ____ make the restoration less likely to fracture

Answer 21

perpendicular; occlusal forces

Question 22

_____ internal line angles on a preparation (at least a little bit) make the tooth less likely to fracture

Answer 22

rounding

Question 23

Smoothing rounding the outline form makes the ____ less likely to fracture

Answer 23

restoration

Question 24

Preparing to ____ prevents weakness (resists fracture) in the restoration

Answer 24

proper depth

Question 25

Never leave ____ on the floor of a preparation

Answer 25

enamel

Question 26

Never leave a ____ on the enamel wall of an occlusal preparation, like a class I amalgam

Answer 26

partial-depth ledge

Question 27

Avoid leaving ____ under an amalgam that is subject to occlusal stress

Answer 27

sharp external line angles

Question 28

A buccal pit amalgam can be classified as:

Answer 28

Class I

Question 29

A class I buccal pit amalgam occurs in the ____ tooth

Answer 29

occlusal 2/3 of molar

Question 30

A class I buccal pit amalgam restores a:

Answer 30

developmental pit

Question 31

despite being on axial surface, a buccal pit amalgam is NOT a:

Answer 31

class V

Question 32

For a buccal pit preparation, use the ____ bur. It flutes are _____ top-to-bottom so they are a gauge for the proper depth

Answer 32

330; 1.5mm

Question 33

The 330 bur is a ____ shape so it naturally_____.

Answer 33

inverted cone; converge walls

Question 34

Describe whether the following should be converging or diverging 1. buccal walls in isthmus area: 2. lingual walls in isthmus area: 3. distal wall: 4. lingual wall of lingual groove: 5. mesial wall: 6. Wall at buccal groove:

Answer 34

1. converging 2. converging 3. diverging 4. diverging 5. diverging 6. diverging

Question 35

Walls at the terminal ends of the buccal and lingual grooves should diverge ____ degrees

Answer 35

3

Question 36

Walls in the isthmus areas converge ___ degrees on each side of the preparation, isthmus width is ___ minimum

Answer 36

3 degrees; 1 mm

Question 37

Walls adjacent to marginal ridges ___ by ___ degrees

Answer 37

diverge; 3 degrees

Question 38

Diverging the mesial or distal wall adjacent to the marginal ridge leaves ____ for the ridge in this area

Answer 38

dentin support

Question 39

Occlusal amalgam depth:

Answer 39

.3 mm inside the DEJ

Question 40

Converging the wall adjacent to the marginal ridge risks ____ for the marginal ridge

Answer 40

destruction of the dentin support

Question 41

How can you avoid an off-axis preparation?

Answer 41

Enter teeth parallel to the long axis of the crown, not the patient

Question 42

Bur inclines more medially in the ____ and more distal in the ___ the further posterior we go, do to the ___

Answer 42

mandible; maxilla; curve of Spee

Question 43

Bur inclines more lingually in the ____ and more bucally in the ____ the more posteriorly we go, due to the ____

Answer 43

mandible; maxilla; curve of Wilson

Question 44

If the preparation is still in the enamel it is:

Answer 44

too shallow

Question 45

Angular outline form could cause:

Answer 45

areas of stress concentration

Question 46

The 169 bur will give a slightly ____ prep since it is a ____ shaped bur.

Answer 46

diverging; tapered fissure

Question 47

The #169 bur flute measures ____ top to bottom

Answer 47

4mm

Question 48

Shape and depth of 245 bur:

Answer 48

inverted cone w/ rounded edges on its flat end; 3mm

Question 49

Restores caries on the gingival 3rd of the buccal and lingual surfaces of teeth

Answer 49

Class V preparation

Question 50

Almost all caries start ___, but often spreads ___ onto the root surface

Answer 50

supragingivally; subgingivally

Question 51

In a class V amalgam preparation, the axial wall is ____, and a ____ should be present

Answer 51

convex; gingival retention groove

Question 52

A gingival retention groove in a class V amalgam preparation is located:

Answer 52

in the dentin, just inside the DEJ

Question 53

Enamel on the cervical area is ____ compared to the occlusal area

Answer 53

thinner

Question 54

In class V preparation, since the prep is in a smooth area, the outline form is determined by:

Answer 54

extent of caries (rather than following anatomy)

Question 55

In a class V amalgam prep, since the prep is in a convex surface and all amalgam margins must be 90 degree; all walls ____ and ____ are needed for retention.

Answer 55

diverge; grooves

Question 56

In a class V amalgam prep, the axial wall is ___ when caries is minimal

Answer 56

convex

Question 57

When caries extend on to the root surface/subgingival, the rules for ____ may change

Answer 57

depth

Question 58

When caries extend on to the root surface/subgingival the rules for depth may change: A- When there is a minimum thickness of enamel: B- When margin is on the root:

Answer 58

a- 1mm depth b- 0.75mm depth

Question 59

Describe the placement of a retention groove in a Class V buccal amalgam prep: What if its an extremely deep prep?

Answer 59

Entirely in dentin just inside DEJ the groove still go just inside the DEJ

Question 60

What is used to remove undermined enamel inter proximally?

Answer 60

gingival margin trimmer