Cavity Preparation

Question 1

Name the G.V. Black classification of caries:

Carious lesions affecting
1. Fissures and pits
2. Occlusal thirds of premolars and molars
3. Buccal and lingual pits of molars
4. Linguals pits of upper incisors

Answer 1

Class I

Question 2

Name the G.V. Black classification of caries:

Carious lesions affecting:
- proximal surfaces of posterior teeth (molars and premolars)

Answer 2

Class II

Question 3

Name the G.V. Black classification of caries:

Carious lesions affecting:
- proximal surfaces of anterior teeth (incisors and canines) WITHOUT the involvement of the incisal edge

Answer 3

Class III

Question 4

Name the G.V. Black classification of caries:

Carious lesions affecting:
- proximal surfaces of anterior teeth WITH involvement of the incisal edge

Answer 4

Class IV

Question 5

Name the G.V. Black classification of caries:

Carious lesions involving the:
- gingival third of facial and lingual surfaces of any tooth along the gumline

Answer 5

Class V

Question 6

Class V lesions are a frequent site of decay for individuals with _______________ or _______________.

Answer 6

poor oral hygiene or exposed root surfaces

Question 7

Name the G.V. Black classification of caries:

Caries involving the:
- Incisal edge of anterior teeth (incisors and canines)
- Cusp tip(s) of posterior teeth (premolars and molars)

Answer 7

Class VI

Question 8

What are class VI lesions often caused by?

Answer 8

initial abrasion and erosion

Question 9

In a completed cavity preparation, there is a ____________ outlining the preparation containing the external and internal preparation walls.

Answer 9

cavosurface margin

Question 10

the junction of the cavity preparation and the external tooth surface

Answer 10

cavosurface margin

Question 11

refer to the distinct walls which contact with an edge with the cavosurface margin, named according to the outer tooth aspect that they are parallel and closest to

Answer 11

external walls

Question 12

Internal walls are classified based on their plane of dimension:
- Wall that runs parallel to the long axis of the tooth?
- Walls that runs perpendicular to the long axis of the tooth along the base of the prep and above the pulp chamber

Answer 12

Axial wall
Pulpal wall/floor

Question 13

The junctions of preparation walls are also named based on their intersecting walls:

Where 2 walls meet?
Where 3 walls meet?

Answer 13

line angle / point angle

Question 14

8 steps of a cavity preparation according to G.V. Black:

Answer 14

1. Outline form
2. Resistance form
3. Retention form
4. Convenience form
5. Removal of remaning caries
6. Pulp protection
7. Secondary retention and resistance form
8. Finishing of external walls

Question 15

establishes the external outline of the preparation and cavosurface margin, determined by the extent of carious lesion

Answer 15

outline form

Question 16

Requirements of the outline form of a prep include:
- Initially extend ______mm into the dentin of sound tooth structure just below the DEJ, only extend depth if deeper caries exist
- For Class IIs, extension of gingival floor to get _____mm clearance with adjacent tooth
- Removal of ________ enamel

Answer 16

0.2mm / 0.5mm / unhealthy (friable enamel, unsupported enamel)

Question 17

What is the exception to the rule that says facial and lingual proximal walls require an extension of 0.5mm clearance to the adjacent tooth?

Answer 17

if it would require an unnecessary removal of sound tooth structure to open the contact

Question 18

demineralized enamel which cannot be effectively bonded

Answer 18

friable enamel

Question 19

enamel with no underlying dentinal support which cannot support cyclic loading

Answer 19

unsupported/undermined enamel

Question 20

a design developed to allow for the tooth and restoration to withstand the forces of mastication and not fracture, prevention of the tooth or restoration from OCCLUSAL forces

Answer 20

primary resistance form

Question 21

Requirements of this include:
- horizontal and flat gingival and pulpal floors
- rounded internal line angles to reduce stress concentration
- preservation of cusps and marginal ridges to maintain tooth strength

Answer 21

primary resistance form

Question 22

Preservation of cusps and marginal ridges is important in maintaining the tooth’s strength. Consider capping the cusp when…?

Answer 22

the extension is greater than half the distance from the primary groove to the cusp tip.

Question 23

refers to design features that prevents the displacement of restorative material during function

Answer 23

primary retention form

Question 24

Requirements of this include:
- occlusal surface preps must have external walls to prevent occlusal displacement
- dovetail feature to prevent proximal displacement

Answer 24

primary retention form

Question 25

involves extending the prep for visibility and access

Answer 25

convenience form

Question 26

liners vs bases in pulp protection

Answer 26

Liners
- provide a barrier to protect the dentin
- provide thermal protection
- promote tertiary dentin formation
- materials include calcium hydroxide (Dycal) or RMGI

Bases
- used for metal restorations or on top of liners to protect liners from being absorbed or washed away
- provide thermal protection
- help stress distribution
- materials include RMGI (Vitrebond) or GI cement

Question 27

Indications for use of indirect pulp cap vs direct pulp cap vs endo:

Answer 27

Deep excavation approximating the pulp requires an indirect pulp cap with base material.

<1mm diameter ASYMPTOMATIC pulp exposure requires a direct pulp cap with liner and base.

> 1mm diameter symptomatic pulp exposure via carious or mechanical means requires pulpotomy or RCT.

Question 28

a common desensitizing agent which minimizes dentinal tubular fluid movement by occluding dentinal tubules through the cross-linking of tubular proteins

Answer 28

GLUMA

Question 29

content of GLUMA

Answer 29

glutaraldehyde 5%, HEMA 35%, water

Question 30

examples of secondary resistance and retention form indicated for larger restorations (3)

Answer 30

retentive grooves
beveled enamel margins
slots/pins

Question 31

Name the secondary resistance and retention form: shallow grooves designed to prevent material from being dislodged proximally or occlusally

Answer 31

retentive grooves

Question 32

Name the secondary resistance and retention form: provide more surface area for enamel bonding with composite

Answer 32

beveled enamel margins

Question 33

Name the secondary resistance and retention form: used for retention during advanced amalgam restorations where a cusp wall may be missing

Answer 33

slots/pins

*Most common pin = self-threaded
*Slots need to be at least 1mm deep, 1mm long, and 0.5mm inside the DEJ

Question 34

this is the last step before progressing to the restoration phase, involves insuring smoothness of the cavosurface margin and inspecting for a clean prep

Answer 34

finishing of external walls

Question 35

methods of moisture control

Answer 35

rubber dam, suctions, cotton rolls, LA

Question 36

Amalgam preps require a ________ bur for _______ walls.

Composite preps require a _______ bur for ________ walls. This creates more surface area for better binding retention.

Answer 36

Amalgam- carbide bur, smooth walls
Composite- coarse diamond bur, rough walls

Question 37

Preparation step specific features for an amalgam prep include (3):

Retention form
Resistance form
Amalgam thickness

Answer 37

Retention form- occlusal convergence (primary), grooves/slots/pins (secondary)

Resistance form- 90 degree cavosurface margin, preservation of cusps and marginal ridges, flat pulpal and gingival floors, removal of unsupported tooth structure, rounded internal line angles

Amalgam thickness- 1.5-2mm

Question 38

Composite restorations have similar requirements as amalgam, but require less __________ features.

Answer 38

retentive

Question 39

advantage of composite over amalgam

Answer 39

occlusal convergence and uniform depth are not as crucial to material success, allowing for more conservative preps

Question 40

Secondary resistance and retention form features of gold onlay preps:

Answer 40

Collar- beveled shoulder around capped cusp
Skirt- feather edged margin around capped cusp