Cavity Lining Materials Flashcards

1
Q

What is the purpose of a lining material?

A

Prevent gaps within the restorative material and act as a protective barrier over the pulp.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why is it important to place a liner under an amalgam restoration?

A

Amalgam has a very high thermal diffusivity and thermal conductivity. So a liner acts to protect the pulp from temperature that could be transferred through the restoration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a cavity base?

A

Thick mix placed in bulk.
Dentine replacement used to minimise the bulk of the material or block out undercuts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a cavity lining?

A

Thin coating of material over exposed dentine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the purpose of a liner?

A

Protection from thermal, chemical or bacterial stimuli.
Therapeutic- calm down inflammation within the pulp and promote plural healing.
Palliative- reduce patient symptoms prior to definitive treatment being carried out.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the ideal properties of a lining material?

A

Easy to mix
Long working time
Short setting time
Low thermal conductivity
Similar thermal expansion and thermal diffusivity to dentine.
High compressive strength
EM similar to dentine
Radiopaque
Form a chemical bond to dentine
Low solubility
Cariostatic
Biocompatible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What type of setting reaction occurs in setting calcium hydroxide?

A

Chelation reaction between zinc oxide and butylene glycol disalicylate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the name of setting calcium hydroxide?

A

Dycal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the mode of action of setting calcium hydroxide?

A

High alkaline pH of Dycal kills cariogenic bacteria.
The cement causes irritation tot he odontoblast layer of dentine, tertiary dentine forms and this forms a calcified bridge, walling off the base of the cavity to the pulp.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why must you always cover setting calcium hydroxide with RMGI?

A

It is very unstable and soluble, if the cavity leaks, then the lining will disappear.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a use of setting calcium hydroxide?

A

Place over an exposed pulp.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What reaction occurs in zinc oxide eugenol cement?

A

Acid base reaction between zinc oxide and Eugenol.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why can ZOE not be used under amalgam restorations?

A

Low compressive strength- would crumble under the pressure of amalgam packing into the cavity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why can ZOE not be placed under a composite restoration>

A

Eugenol inhibits the set of resin based filling materials, softens them and causes discolouration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why is resin modified ZOE better than conventional ZOE?

A

Resin modified ZOE has resin added, which does not take part in the setting reaction but gives it a stronger back bone to the set material.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the generic name for resin modified ZOE?

A

Kalzinol.

17
Q

Why is glass ionomer a good lining material?

A

Bonds directly to dentine and seals the dentine tubules.
Bond directly to composite that is placed over it.
Releases fluoride over time.

18
Q

Why is RMGI (vitrebond), the gold standard cavity lining material?

A

Least soluble
Releases benzoyl iodide and benzoyl bromides which can kill some remaining bacteria present
Bonds directly to composite.

19
Q

Which material should be used as a liner when the dentine quality is poor?

A

RMGI (vitrebond).

20
Q

When should setting calcium hydroxide be used?

A

When the cavity approaches the pulp.

21
Q

What criteria need to be met for you to apply a direct pulp cap?

A

Dentine surrounding the exposure is sound
Red, homogenous and blood filled tissue is observed on the surface of the pulp wound, with no yellowish, liquefied areas or dark non-bleeding zone.
Haemostats can be achieved within 203 minutes.

22
Q

What is the role of a direct pulp cap?

A

induce hard tissue formation by odontoblasts that sea the exposure and contribute to pulp vitality.

23
Q

What clinical and radiographic signs will be evident, if direct pulp capping has been successful?

A

Mineralised barrier over the pulp.
- dentine bridge.
Positive pulp vitality tests.
Pulp tissue free from inflammation and no PA pathology.

24
Q

What are some limitations of setting calcium hydroxide?

A

Poor bonding to dentine.
Mechanical instability and continuous resorption after placement.
Dentine bridge that forms can be porous, allowing micro-organisms access to the pulp.