Conservative Dentistry 4 : 1-Cavity Design / First Semester

Front 1

Name the six main principles of cavity design .(6)

Back 1

1) Establishment of outline form
2)Establishment of resistance form
3) Establishment of retention form
4)treatment of residual carries
5)correction of enamel margins
6)cleaning of the cavity ( cavity toilet )

Front 2

Define the "Outline form "

Back 2

"is the shape which the CAVOSURFACE line angle of the cavity assumes after prepreation

Front 3

Outline form --> Access : what's the two things about access ?

Back 3

1) gain initial access via the most carious part of the tooth
2) remove all unsupported enamel to expose the entire exttnet of the caries

Front 4

Outline form --> Elemenation of carious lesion : talk about the elemenation of carious lesions .

Back 4

it's the elemenation of any infected carious tooth strcture left in the tooth AFTER intial cavity prepreation

carries left in the pulpal and axial floor is excavated througlhy making the cavity deeper

all the soft deinte should be REMOVED

Front 5

how many mm should cover the pulp ?

Back 5

0.75 mm - 1.00 mm of dentien should cover the pulp

Front 6

Outline form --> placement of cavity margins in areas of lessened carries susceptibiltiy

Back 6

No always necssary in low carries patients

it is advisable to include the pits and fissures in an amalgam cavity in cases of high caries rate patients

Front 7

What's Convenience ? ( $outline form )

Back 7

Make the cavity wide enough to admit the instruments you are using.

Extend proximal cavities buccally and lingually just outside the contact area.

Front 8

What's Resistance form ?

Back 8

is the design of a cavity in such a way that the remaining tooth substance and the restorative material can withstand masticatory stress.

both the tooth and the restorative material

Front 9

What are the six attributes that must be found in the tooth to achieve retention

Back 9

1.Flat Floor

2.Adequate bulk of the restorative material

3.Absence of weak cusps or marginal ridges

4.Occlusal cavity margins in areas not subjected to excessive occlusal trauma . In practice one-quarter (1/4) of the intercuspal width

5.Flat floor at right angles to the line of stress
6.Walls of the cavity parallel to the direction of the stress

Front 10

Resistance form --> abscene of weak cusps or marginal ridges

Back 10

Remove any weak cusp and restore with a (((metallic material.)))

remove any weak marginal ridge specially if it is not supported by sound dentine. This way class I becomes Class II

Front 11

Resistance form --> Adequate bulk of the restoration

Back 11

The depth should be enough to take adequate bulk of the restorative material which can withstand forces of mastication.

Amalgam thickness should be 1.5 – 2 mm at least.

Front 12

resistance form --> Occlusal cavity margins in the areas not subjected to excessive occlusal trauma

Back 12

Occlusal margins of the cavity should not be subjected to heavy stress.

Place them about 1/4 of intercuspal distance.

Front 13

Resistance form --> Flat floor at right angles to the line of stress:

Back 13

Make the floor of the prepared cavity flat

Make the floor of the cavity at right angles to direction of the occlusal forces.

VERY IMPORTANT --> No sound tooth structure should be removed to achieve this.

Front 14

Resistance form --> Walls of the cavity parallel to the direction of stress:

Back 14

Make the walls of the cavity parallel to the corresponding surfaces.

Front 15

List all the resistance form factors

Back 15

Adequate bulk of the restoration

Occlusal cavity margins in the areas not subjected to excessive occlusal trauma

Flat floor at right angles to the line of stress:

Walls of the cavity parallel to the direction of stress:

Front 16

What's "retention form " ?

Back 16

refers to those aspects of cavity preparation which ensure that the restoration is not dislodged from the prepared cavity.

Front 17

List all the retention form factors

Back 17

Undercuts

Dovetail lock

Flat floor and definite internal line angles

Grooves and boxes

Acid etch technique

adhesives

Front 18

How do we treat residual carries ? ($residual carries )

Back 18

Amelodentinal junction caries

Pulpal caries

Indirect pulp capping

Front 19

Talk about correction of enamel margins

Back 19

No undermined enamel rods

Smooth enamel surface

Cavosurface angle 90

No beveling for amalgam

Composite needs a bevel to provide greater enamel surface area for etching and micromechanical retention.

Front 20

Talk about cleaning of the cavity

Back 20

The prepared cavity should be free from all debris

No disinfectant should be used to clean the cavity.

Don’t desiccate it.

Front 21

Talk a little about G.V Black

Back 21

"The Grand Old Man of Dentistry"

"The professional man has no right to be other than a continuous student."
The complete divorcement of dental practice from studies of the pathology of dental caries, that existed in the past, is an anomaly in science that should not continue. It has the apparent tendency plainly to make dentists mechanics only

Front 22

what was the Critique of G.V Black principles ?

Back 22

It does not include root caries

It does not include secondary caries

It does not include non-carious lesions which are treated in the same way as carious lesions

Front 23

What are The objectives of restoring teeth ?

Back 23

To remove diseased tissue as necessary

To restore the integrity of the tooth surface

To restore the function of the tooth

To restore the appearance of the tooth

Front 24

What determines cavity design?

Back 24

1. The dental tissues

2. The disease

3. The properties of the restorative material

Front 25

The dnetal tissue --> enamel

Back 25

Enamel is the hardest tissue in the body, inelastic and brittle. Tend to split along the line of rods

Unsupported enamel vs. composite and GIC

Unsupported enamel vs. amalgam

Unsupported enamel and tightening a matrix band

Front 26

the dental tissue --> dentine

Back 26

Dentine is softer than enamel, more porous and sensitive.

Dentists can use pins

Dentine and pulp are considered one unit.
Why?

Diseases or operative procedures that affect the dentine may also affect the pulp

Front 27

The dental tissue --> pulp

Back 27

Pulp size and secondary dentine

The preparation is designed to avoid pulp

Avoid physical, chemical or thermal trauma to the pulp during cavity preparation and placing the restoration

Front 28

the dental tissues --> the gingiva

Back 28

The cavity design and restoration should have minimal encroachment on the gingiva

The margins of the restoration should be smooth and not retentive to plaque

The margins should be cleansable as possible

Front 29

What are the two things we need to consider the spread of carries ? ($the disease )

Back 29

1) pulpal

2) Lateral Spread

Front 30

List the proprieties of amalagam

Back 30

Mechanical retention

Weak in thin sections

Is not tooth colored

corrosion forms at the tooth amalgam interface

Needs force to be condensed into cavity

Front 31

List the proprieties of compiste

Back 31

It is attached physically to the tooth by means of acid etch

It is strong in thin sections

Can be attached to dentine by chemical bonding or via intermediate layer of GIC

Shrinkage is a problem

Front 32

List the probrites of GIC

Back 32

Chemical adherence to enamel and dentin

It releases fluoride slowly

Margins can be left in areas which are difficult to clean

Weak and not abrasion resistant

Cermet contains silver to make abrasion resistance and radiopaque

They destroy the tooth like appearance

Front 33

List the "New principles of cavity design"

Back 33

gain acess

remove carries

look, think and design

complete the restoration

Front 34

Gaining access – class II

Back 34

Remove the marginal ridge
Via the buccal or lingual surfaces

Tunnel through from the occlusal surface leaving the marginal ridge intact

Direct access when the adjacent tooth is missing

Front 35

Look, think and design

Back 35

The final choice of material

Retention

Protection of remaining tooth structure

Optimize strength

The shape and position of cavity margins

Front 36

Design features to protect remaining tooth structure

Back 36

Remove unsupported enamel

Remove weakened cusps

Support the weak structure by bonding it to other parts of the tooth with GIC

Have it crowned

Front 37

Design features to optimize the strength of the restoration

Back 37

Remove sufficient tooth tissue to make room for the material taking into consideration its properties

Round the occlusal-proximal line angle

Front 38

Position of cavity margins

Back 38

Place cavity margins supragingivally

Don’t extend beyond the contact area unnecessarily

Do not leave sharp edge of an amalgam restorations

Front 39

How injury to the pulp might happen ?

Back 39

Pulpal injury can result due to:
1.Heat generated by injudicious cutting.
2.Restorative material with good thermal conductivity.
3.Chemical from the restorative materials.
4.Galvanic currents
5.Microleakage.

Front 40

Cavity lining and chemical preparations

Back 40

1))Linings: e.g. calcium hydroxide, zinc oxide eugenol and GIC. These are protective, therapeutic and structural

2. Varnishes: natural or synthetic resins in a solvent and are applied to cavity walls in an attempt to improve the marginal seal of an amalgam restoration