Principles of caries removal and prep

Question 1

What determines cavity design

Answer 1

Structure and properties of the dental tissues​

The diseases (dental caries, periodontal disease, tooth surface loss)​

Properties of restorative materials

Question 2

When should a dentist intervene

Answer 2

When the lesion is cavitated
When the patient can’t access the lesion for prevention
When the lesion has entered the dentine radiographically
The lesion is unaesthetic

Question 3

What is the structure of tertiary dentine and why is it important to consider with caries

Answer 3

Less organised, tubulestructure different which affects how restorative materials stick to it

Question 4

What are the properties of dentine to consider when placing restorations

Answer 4

Type 1°/2°/3°​

Intra/Inter/Peri tubular​

Diameter​

Density​

Contents/Mineralization

Question 5

What are the principles of preparation

Answer 5

-Caries removal ​
-Necessary finishing required for:

Maximising adhesion​
Occlusal relationships​
Ease of patient cleaning ​
Properties of the materials used​

Question 6

When might you consider removing healthy tooth tissue

Answer 6

The material used for the restoration requires it
The margins of the cavity cross an occlusal contact

Question 7

Outline the principles of caries removal and cavity prep

Answer 7

Identify and remove carious enamel​

Remove enamel to identify the maximal extent of the lesion at the amelodentinal junction & smooth the enamel margins​

Progressively remove peripheral caries in dentine – from the ADJ first, then circumferentially deeper.​

Only then remove deep caries over pulp​

Outline form modification (cavo-surface margins)​
-Enamel finishing​
-Occlusion​
-Requirements of the restorative material​

Internal design modification​
-Internal line and point angles​
-Requirements of the restorative material

Question 8

PA (point angle)

Answer 8

Junction between 3 surfaces

Question 9

What is a Line angle

Answer 9

a junction between two surfaces

Question 10

What are the factors of a final seal

Answer 10

Smooth margins​

Appropriate CSMA​

No unsupported tooth tissue​

No stress concentrators​

Internal anatomy that allows adaptation of material

Question 11

Cavo-surface margin angle

Answer 11

the angle of tooth structure formed by the junction of a prepared (cut) wall and the external surface of the tooth

Question 12

What are the beginning steps to dealing with caries

Answer 12

1st Principle – Access​

Apply Dam​

Remove overlying enamel with a high-speed bur to gain access to carious dentine​

HIGH-SPEED ACCESS​

Follow the caries at the ADJ​

Do not extend into non-carious areas​

Question 13

What is the 2nd principle of caries removal

Answer 13

2nd Principle - Extent​

Caries spread at ADJ determines outline form encloses extent of caries​

Clear all caries at ADJ​

Check Staining at ADJ​

Smooth enamel Cavo-surface margins​

Examine adjacent contact for caries​

Avoid trauma to adjacent tooth​

Question 14

How should an existing restoration be removed

Answer 14

NEVER remove a restoration by cutting around the edges - you will increase the size of the cavity unnecessarily​

Start from the centre of the restoration and cut towards the edge of the cavity​

Question 15

What does sticking of the probe on dentine indicate

Answer 15

Residual carious dentine which should be removed

Question 16

How can we identify carious dentine

Answer 16

Brown stained or softened tissue when using sharp probe

Question 17

When should stained tooth be left

Answer 17

When hard under the probe

Question 18

What are the rules for removing residual carious dentine

Answer 18

Residual carious dentine must be removed first from the amelo-dentinal junction (ADJ) and last from the pulpal floor

Question 19

How should caries on the pulpal floor be removed

Answer 19

Caries on the pulpal floor should be removed last using the largest instrument which will conveniently work in the cavity:​

Large round bur​

Large hand-held excavator​

Chemo-mechanical caries removal​

Question 20

How do you manage pulp exposure

Answer 20

Pulp therapy such as pulp cap (CaOH)

Question 21

What is the 4th principle

Answer 21

Modifications
How can the tooth be modified to yeild the best result for the restoration (i.e. smoothing enamel margins)

Question 22

What is needed for amalgam to stick

Answer 22

REMOVAL OF EXCESS TOOTH
Features of the cavity which prevent the restoration being dislodged in any occlusal direction

Anatomical cavity design features: e.g. Undercuts, dovetail, key, isthmus​

Question 23

What cavity margins allow for maximum strength and minimum leakage

Answer 23

Bevel to align orientation with prisms for composite, but consider the best approach to achieve end cut prisms​

Generally, the cavo-surface angle is between 90-120o for Amalgam: Butt joint​

Above all, avoid inappropriate CSMA or fragile enamel​

Question 24

What does AMA, USE and CSMA stand for

Answer 24

AMA -Amalgam margin angle​
USE - Prisms unsupported by underlying dentine
CSMA - Cavo-surface margin angle

Question 25

Why might composite fracture within itself

Answer 25

Polymerisation strees, etch and bong is stronger than interstitial enamel strength. enamel surface wasnt properly prepared before composite was added

Question 26

When do you decide on choice of material

Answer 26

After caries removal

Question 27

Are caries all always removed

Answer 27

No not in all cases