06.liners and bases

4

o Healing/ Repair.

o Pulp’s vitality and function.

o Normal responsiveness to

electrical and thermal pulp tests.

o Preventing breakdown of the

peri-radicular supporting tissue.

oFormation of secondary dentine.

Importance of remaining dentin thickness

0.5 mm

1 mm

2 mm

Remaining dentin

thickness

25 %

10 %

Minimal or Nil

Effect of toxic

substances

Causes of Pulpal Inflammation

Types of stimulus Examples of stimulus

Physical Thermal, electrical

Mechanical Handpiece,

traumatic occlusion

Chemical Dental materials, Caries

Biologic Bacteria from saliva

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•Immature permanent teeth or

mature permanent teeth with

simple restorative needs.

II- Indications of direct pulp capping

7

Small pinpoint pulp exposure=1mm

•Recent traumatic (<24 h)/Mechanical pulp

exposure

8

•Little or no bleeding at the exposure site

9

•NO PULP

VITALITY

10

•No pulp calcification

•Inflammatory signs/ symptoms 13

•primary teeth root resorption

14

•Pre-operative

tooth sensitivity

15

•Large

pulp exposures

•Uncontrolled

bleeding

16

•Non-restorable tooth

or restorable with low

prognostic

Dentin Bridge

Classification and types

• CAVITY SEALERS: Varnish, Adhesive sealers

• CAVITY LINERS: Glass ionomer, Calcium hydroxide

• Bases: - 1. Zinc phosphate cement.

2. Reinforced zinc oxide / eugenol cement.

3. Zinc polycarboxylate cement.

4. Glass ionomer cement.

Cavity sealers

• Varnish

• Adhesive sealers

• Provide protective coating and barrier to leakage

• Coat all walls of the cavity

• Provide various degrees of seal

Varnish

• Material applied in thin film thickness usually 2 –5 microns.

• It could be applied to all prepared cavities on both enamel and dentin.

• Protective coating and Barrier to leakage

• Seals the dentinal tubules and reduces leakagearound a restoration.

• Provides no thermal

insulation

Varnish

Composition:

• Organic resin or synthetic gum dissolved in solution of ether, chloroform or acetone.

• This solution evaporates rapidly after placement on the tooth leaving a thin layer of semi-permeable membrane.

• The thickness of this layer is 5 – 25 microns depending on the type of the solvent and the number of applications.

• Application process

– Applied with either a small disposable applicator or a cotton pellet.

– Thin coating of the varnish on the walls, floor, and margin of the cavity preparation.

– Apply a second coat.

Contraindication:

- Composite – free monomer layer dissolves the varnish

- Ca(OH)2/ ZOE beneficial affects are lost

- Polycarboxylate – interferes with adhesion

- GIC – blocks fluoride penetration.

Adhesive sealers

• Provide sealing as well as bonding at the interface between restoration and cavity preparation walls.

Concerns about use of adhesive sealers under amalgam

• Barrier to corrosion products

• More technique sensitive than varnishes

• Expensive and time consuming

• Pooling of resin

• Incorporation into amalgam

Liners:

Definition: It is liquid in which CaOH and zinc oxide

(occasionally) are suspended in a solution of natural

or synthetic resins.

Composition:

1. Ca(OH) / ZnO – Therapeutic agent

2. Ethyl alcohol – Solvent

3. Ethyl cellulose – Thickening agent

4. Barium sulfate – Radiopacifier

5. Fluorides – Anticariogenic

Manipulation:

Trade names: Dycal and Life

It is available as 2 paste systems both of which contain

Ca(OH) and one consists of accelerator

Equal amounts of material from each tube is collected over a

glass slab or mixing pad with help of probe (Applicator) both

are mixed till homogeneous colour is achieved and with

same instrument it is carried.

- to deepest portion of the cavity and since it is fluid in

consistency it readily flows or gets painted over the cavity

over which the thermal insulating base or temporary

restoration is provided.

Properties:

1. Acts as a thin barrier between the restoration and theremaining dentine and protects the pulpal tissue fromirritation caused by physical, mechanical, biological, orchemical agents .

2. Like cavity varnish it neither possesses mechanical propertiesnor provides thermal insulation.

3. Should not be applied on cavity margins.

Uses:

1. As pulp capping agent due to its sealing ability.

2. As anticariogenic cement because it stimulates the production of secondary or reparative dentin.

3. Prevents post operative sensitivity or pain.

4. It is compatible with all types of restorative materials.

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IV- Pulp capping materials

•Calcium Hydroxide Ca(OH)2

•Mineral TrioxideAggregate MTA

•Tri-calcium phosphate

•Bioaggregate

•Biodentine

•Bonding Systems

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•The most common direct

pulp-capping agent

•Antibacterial and

disinfects the superficial

pulp

•High pH (about 12.5)

Pure Calcium

hydroxide

Calcium hydroxide Ca(OH)2:

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How does Ca(OH)2 work??

•Liquefaction necrosis of the superficial pulp

•Neutralization of toxicity in deeper layers

•Coagulative necrosis…Irritation of adjacent

pulp

•Minor inflammation response… Hard tissue

barrier

20

•Pure calcium hydroxide are more

caustic than Hard-setting calcium

hydroxide pastes (Dycal, Life,…)

but both have been shown to

initiate the same type of healing

Properties:

21

• Dentin bridges beneath calcium

hydroxide pulp caps contain ‘tunnel

defects’, therefore an additional

base material is necessary to seal the

exposed pulp from the external

environment.

•Calcium hydroxide materials tend to soften, disintegrate,

and dissolve over time.

22

Mineral Trioxide Aggregate or MTA:

ProRoot

To seal communications between

the root canal system and the

external tooth surface at all

levels and recently indicated in

pulp treatment as direct pulp

capping.

Dr M.Torabinejad

23

Composition:

•Tricalcium silicate

•Tricalcium aluminate

•Tricalcium oxide

•Silicate oxide

Mixed with sterile water in a 3:1 powder-to-liquid ratio,

MTAsets in 5 minutes

24

Application of MTA

25

Properties:

•Low or no solubility

•PH value10.2 after mixing and rises to 12.5 after 3 hours

•Antibacterial effect

•Induces pulpal cell proliferation

•Stimulation of mineralized tissue formation

26

Process not yet known

Tri-calcium oxide + tissue fluids = calcium hydroxide

Hard-tissue formation

How does MTAwork??

28

Tri-calcium phosphate:

- Bone regeneration procedures (promotes effects on

hard tissue formation by osteoblasts)

- Studies showed that dentinal bridge

formation does take place, by direct apposition, on the

pulpal wall

The bridge:

•Contiguous

•Thick

•Minimal pulpal inflammation

•Odontoblasts directly under and in contact with the

bridge

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Bio-Aggregate

Indicated as:

• Repair of Root Perforation

• Repair of Root Resorption

•Apexification

• Pulp Capping

Bio-Aggregate is a root canal

repair material composed of

bio-ceramic nano-particles

30

Pure white powder and liquid mixed together to form

a thick paste-like mixture.

32

Biodentine™ :

Active Biosilicate

Technology™ /calcium

Silicate based cement

Dentin substitute from Septodont

33

Indications:

•Endodontic indications (repair of perforations or

resorptions, apexification, root-end filling)

•Permanent dentine substitute and temporary enamel

substitute

•Restoration of deep or large crown carious lesions

•Direct pulp capping in adults presenting healthy pulp

34

Formulation:

Powder

Tri-calcium Silicate (C3S) Main core material

Di-calcium Silicate (C2S) Second core material

Calcium Carbonate and Oxide Filler

Iron Oxide Shade

Zirconium Oxide Radiopacifier

Liquid

Calcium chlorideAccelerator

Hydrosoluble polymer Water reducing agent

40

1-Anesthesia

2- Rubber dam

VI- Techniques of direct pulp capping

41

3- Chlorhexidine solution

4- Rinse with anesthetic or sterile saline

42

5- sterile cotton

pellet to control

bleeding

6-Mix capping agent

43

7-Apply to exposure site

8- Base/liner then restore

The bestPermanent filling process consists of

covering the pulp capping material with a RMGIC

followed by a hermeticcomposite resin

restoration to prevent bacterial leakage and

recontamination of the exposed area.

46

Bases

• Insulation

• Bulk build up

• Blocking of undercuts

• Resin composite exhibits low thermal diffusivity that a thermal insulating base should be unnecessary

• Insulating base for thermal protection should be used under metallic restorations

• Thickness 0.5-0.75 mm