cavity liners and bases

VARNISH

Composition

Manipulation

Properties

Uses

Definition:

It is a natural gum like copal rosin or synthetic

resin dissolved in organic solvents such as ether,

chloroform or alcohol

Composition:Composition:

Copal and nitrated cellulose are typical examples of natural

gum and the solvents used to dissolve these materials can be

ether, acetone benzene, ether acetate, ethyl alcohol,

chloroform, amylacetate and medicaments such as

chlorobutanol, thymol and eugenol are also added. Recently

fluoride are included in its composition.

Manipulation:

On a patient, Cavity varnish is applied with the help of small

cotton pellet with the help of wire or R.C Reamer or a brush

applicator. Thin layers of varnish are applied on the floor,

walls including cavosurface margins. Gentle stream of air

can be used to remove the excess and bottle should be

tightly capped after use to minimize loss of solvent.

Contraindication:

- Composite – free monomer layer dissolves the varnish

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

- Polycarboxylate – interferes with adhesion

- GIC – blocks fluoride penetration.

Properties:

1. It is not a physical or mechanical insulator, provides

chemical barrier.

2. Thickness: 2-40m

3. Always applied in 3 layers to be more effective

Uses:

1. Prevents marginal Leakage / Microleakage

2. Prevents penetration of acids from ZnP cement i.e

prevents chemical penetration.

3. Prevents penetration of corrosion products from

amalgam therefore prevents discoloration of tooth.

4. Decreases post operative sensitivity and pain.

Liners: Liners:

Definition: It is liquid in which CaOH and zinc oxide

(occasionally)are suspended in a solution of natural

or synthetic resins.

Composition: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 PD probe both are

mixed till homogeneous colour is got 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 barrier between the restoration and the

remaining dentine.

2. Like cavity varnish it neither possesses mechanical

properties nor provides thermal insulation.

3. Should not be applied on cavity margins.

Uses:

1. As pulp capping agent.

2. As anticariogenic cement

3. Prevents post operative sensitivity or pain.

BASES

Bases :

Chemical and Thermal, Mechanical Insulation

Cements:

General applications

Classification

Individual Cements - Composition

- Manipulation

- Properties

- Uses

General Applications:

1. Thermal and chemical insulation

2. Temporary restorations – Zn OE

3. Intermediate restorations – IRM

4. Permanent restorations – GIC

5. Temporary Luting – Type I ZOE

6. Permanent Luting – GIC, ZnP, Zn Poly Carb

7. Cementation of orthodontic appliances

8. As sedative dressing for the pulp of freshly prepared tooth

9. As pulp capping agents

10. Pit and fissure sealants – Composites, GIC

11. Core build-up

12. Root canal sealants Gutta-percha

13. Periodontal dressings

Clinical Considerations:

Clinical Judgements about the need for specific liners and

bases are linked to the amount of remaining dentin thickness

(RDT), considerations of adhesive materials, and the type of

restorative material being used.

In a shallow tooth excavation, which includes 1.5 to 2mm or

more of RDT, there is no need for pulpal protection other than

in terms of chemical protection. For an amalgam restoration,

the preparation is coated with two thin coats of a varnish, or a

dentin bonding system, and then restored.

For a composite restoration, the preparation is treated with a

bonding system (etched, primed, coated bonding agent) and

then restored.

In a moderately deep tooth excavation for amalgam that

includes some extension of the preparation toward the pulp so

that a region includes less – than – ideal dentin protection, it

may be judicious to apply a liner only at that site using ZOE or

calcium hydroxide.

Either one may provide pulpal medication, but the effects

will be different. ZOE cement will release minor quantities of

eugenol to act as an obtundent to the pulp.

How ever, in a composite tooth preparation, eugenol has the

potential to inhibit polymerization of layers of bonding agent

or composite in contact with it.

Therefore calcium hydroxide is normally used, if a liner is

indicated. If the RDT is very small or if pulp exposure is a

potential problem, then calcium hydroxide is used to stimulate

reparative dentin for any restorative material.

Cements Used In operative Dentistry:

Silicate Cement

Zinc Phosphate Cements

Zn Silicophosphate Cements

Zn Polycarboxylate Cements

Zinc Oxide Eugenol Cements

Glass Ionomer Cements

Resin Cements

Calcium hydroxide cements

Zinc Phosphate Cement:

Available as Powder and Liquid Powder.

Zn Oxide – 90%

Mg Oxide – 8-9%

SiO2, Bismuth trioxide, Barium oxide – traces

Liquid.

Phosphoric acid (85%) and water (33+ 5%)

Chemistry of Setting:

When the alkaline powder comes in contact with acidic liquid it

partially dissolves in liquid. It is an exothermic reaction. The set

cement consists of hydrated amorphous network of ZnP that

surrounds partially dissolved ZnO2 particles.

Manipulation:

Properties:

1. Mixing time – 60-90secs

2. Setting time – 5-9mins

3. Compressive strength (24hrs) – 13000psi : 103.5Mpa

4. Tensile strength (24hrs) – 800psi 5.5Mpa

5. Film Thickness – 25-40m

6. Solubility/Disintegration – 0.2%

7. Pulp response – Moderate / Severe

8. pH – 3Mins – 3.5

24hrs – 6.6

Because of pulp irritation, cannot be used deep carious

lesions.

Uses:

Primary Uses

1. As luting agent for restorations and orthodontic

appliances.

Secondary Uses:

1. Thermal insulating agent

2. Intermediate restoration

ZINC SILICOPHOSPHATEZINC SILICOPHOSPHATE

It is a combination of silicate and ZnP cement

Properties fall between those of ZnP and silicate.

pH: lower than of ZnP

and has got degree of translucency.

Anticariogenic property because of fluorides.

Zinc Polycarboxylate:

Composition:

Available as powder and liquid

Available as powder to be mixed with plain water

Powder

ZnO

MgO

Traces of other oxides

Liquid:

Polyacrylic acid

Tartaric acid

Maleic acid

Iticonic acid

Properties:

1. Working time : 3-6mins

2. Setting time 5.5mins

3. Mixing time: 30 to 60secs

4. Compressive strength (24hrs): 8000psi

5. Tensile strength: 900psi

6. Film thickness: 21m

7. Pulp response: mild

Binds chemically to tooth structure

Uses:

Primary Uses

1. Luting agent for cementation of restorations

2. Thermal insulating base

Secondary uses

cementation of orthodontic appliances and intermediate

restorations

Advantages over ZnP

- Not irritant to pulp due to high mol. size

- Binds chemically to tooth structure

- Can be used safely in moderately deep cavities.

No need to use cavity varnish.

ZINC OXIDE EUGENOL

Type I : Temporary luting or cementation

Type II: Permanent cementation ex: kalzinol

Type III: Intermediate restoration, thermal insulating

base, temporary restoration.

Type IV: Cavity liners or subbase

Examples:

Type III: IRM

Type IV: Dycal and life

Basic Composition:

As Powder and Liquid

Powder:

ZnO- Main ingredient – 70%

White rosin – reduces brittleness of cement

Zinc acetate – improves strength

Zinc stearate – acts as plasticizer

Liquid:

Eugenol : 85%

Sedative effect to pulp

Olive Oil: 15%

Modifications in basic composition

Type II – Ethoxy benzoic acid/Resins are added increases

the strength of the cement

Type III- Resin reinforced, partially polymerized surface

treated with propionic acid

- Increases strength and abrasive resistance

Type IV – 2 paste system. Active ingredient in both pastes

is Ca OH.

Examples: Type I: Tempbond / Neogenol / Freegenol

II: Kalzinol

III: IRM

IV: Dycal

Chemistry of Setting:

ZnO + H2O Zn (OH)2

Zn hydroxide

Zn (OH)2 +2HE ZnE2 + 2H2O

Base Acid Zn – eugenolate salt

MANIPULATION

Mixed on glass slab or mixing pad. Powder is dispensed and

liquid is collected just prior to the mixing. Bulk of the powder

is incorporated into the mixture and spatulated with a stainless

steel spatula till it becomes paste on creamy in consistency.

Powder or cotton fibers can be added which will improve the

retention of the cement in the cavity.

Properties:

Setting time : 4-10mins

Compressive strength (after 24hrs): 4000psi

Film thickness: 25um

Solution and disintegration: 0.04% by wt

Pulp response mild

Uses:

Primary Application

1. Temporary restoration

2. Intermediate

3. Temporary luting

4. Permanent

5. Thermal insulating base

6. Pulp capping agent

Secondary application

• As root canal sealants and in RC restorations

• Periodontal dressings

CALCIUM HYDROXIDE CEMENT

Available as powder or 2 paste cements

It is available as dry powder or two paste system.

Mixed either with distilled water or saline to form a paste as

it can also be suspended in chloroform and conveyed to the

required area with the help of a syringe

When available as 2 paste cements.

One paste

– monomer of methyl cellulose as initiator and CaOH

Other paste:

Calcium hydroxide and catalyst, when they are brought in

contact methyl cellulose undergoes polymerization and

porous matrix is formed

pH:11

Mechanism of action:

Uses:

1. Cavity liner

2. Pulp capping agents

GLASS IONOMER

CEMENT

Invention,

Composition,

Classification,

Setting Reaction,

Properties,

Variations in basic composition,

Indications,

Contraindications,

Manipulation and clinical procedures for placement.

Invented in 1969 but first reported by Wilson & Kent

1971. It was invented in a creative response to inadequate

materials particularly from deficiencies of silicates.

1. It adheres to tooth structure

2. Translucent

3. Releases fluorides

4.Has also all favorable properties

5. Biocompatible and Bioactive

COMPOSITION

POWDER

Consists of calcium aluminosilicate glass containing fluoride.

SiO2 - 30%

Al2O3 - 19.9%

Al F3 - 2.6%

CaF2 - 34.5%

NaF - 2.6%

AlPO4 - 10%

Radioopacifiers like Strontium, Barium and Lanthanum

Fluoride is one of the main components.

It lowers fusion temperature,

Improves strength provides translucency and therapeutic

value

and improves working characteristics of the cement

Powder particles are obtained by heating all these particles

between 11000 C - 16000 C

LIQUID

Polyacrylic acid which is a polyacrylite which is a polymer

of carbonic acid.

Some amount of maleic acid and itaconic acid is added.

Sometimes poly acrylic acid is blended dry with the powder

so that it is mixed with either water or tartaric acid.

CLASSIFICATION BASED ON USE

Type I: As luting agent

Type II: As restorative agent

Type III: Liners and bases and pit and fissure sealants

Type II: Conventional

Reinforced – Metal modified Glass Ionomers

CHEMISTRY OF SETTING

When the powder comes in contact with the liquid to form a

paste, surface of powder particles are attacked by liquid. Ca,

Al, Na, F ions are released into the aqueous medium.

Calcium polysalts form 1st eventually followed by a Al poly

salts which form cross linking's. They undergo hydration to

form gel matrix and there are untreated powder particles

surrounded by silica gel. Set cement consists of agglomeration

of powder particles surrounded by silica gel in an amorphous

matrix of hydrated Ca and Al polysalts.

PROPERTIES

1. Translucency – mainly due to fluoride

2. Adhesion

3. Biocompatibility

1. Glass Ionomer cement is an esthetic filling material. Its

translucency arises because of powder particles which is

a clear glass. But it takes 24hrs to achieve, mature and

develop full translucency. Only after this period one can

appreciate the colour match with the adjacent tooth

structure.

Color of GIC remains unaffected by oral fluids

unlike composite resins which tends to discolor.

2. It enables the conservative approach for the

restoration because providing mechanical undercuts to retain

the material is not necessary. This is of particular importance

while restoring cervical abrasions and erosions and there will

be a tight marginal seal. Hence less percolation of bacteria

around cavity margins and walls

Type of Adhesion

Chemical bond and can be improved using conditioners

like polyacrylic acid and citric acid.

BIOCOMPATIBILITY

GIC are therapeutic materials. Their adhesion to the tooth

structure ensures a marginal seal thus eliminating secondary

caries by sustained release of fluorides. These materials are not

only biocompatible and bioactive because they promote bone

growth can be used as bone cements after endodontic surgery.

The adverse effects on vital tissues are minimal. Hence a

protective barrier is rarely required

4. Setting time 4-5mins

5. Compressive strength (24hrs): 20000 psi

6. Tensile strength: 400 psi

7. Hardness: 60KHN

8. Solubility and disintegration 0.4% by wt

9. Pulp response – Mild

10. Anticariogenic activity.

Variation in Composition:

1. Miracle Mix

2. Cermet ionomer

GIC are weak in tensile strength. so incorporation of

metal alloy particles into the powder can reinforce the

cement one such product commercially available is miracle

mix.

Here alloy powder particles and glass ionomer powder

particles are mixed by dentist or assistant before mixing

with liquid.

There is improvement in strength.

It does not take up a good surface finish and

cannot be burnished.

Abrasive resistance is less than conventional GIC.

Hence in an attempt to improve these properties cermet

ionomer cements were introduced, in this cement metal

alloy particles like Ag and Au are sintered to the powder

particles which have to be mixed with polyacrylic acid to get

a smooth paste.

These get a good surface finish and can be burnished and

have good abrasive resistance.

But cannot be compared with composites and amalgam.

INDICATIONS:

1.Can be used as a luting agent

2. Can be used for restorations

Restoration of cervical abrasions and erosions without

cavity preparation.

Restoration of class III carious lesions

Restoration of class V carious lesions

3. Pit and fissure sealants

4. Thermal insulating base

5. As cavity liner wherein cariostatic action is required

6. Core building material

7. Tunnel preparation

8. Sandwich technique

CONTRAINDICATIONS

It is a brittle material with low tensile strength and

esthetically not as good as composites therefore cannot be

used in following situations.

- Class II cavity

- Class IV cavity

- Fractured incisal edge

- Lost cusps

- Restorations where esthetic is a prime consideration

MANIPULATION AND CLINICAL PROCEDURE:

1. Select the shade

2. Prepare the cavity required

If remaining dentine is less than 0.5mm provide

Ca hydroxide lining.

3. Isolate the tooth from saliva

4. Apply surface conditioner which will improve

adhesion

5. Wash and gently dry the cavity without dehydrating

dentine

6. Reisolate and dry gently

7. Dispense cement on a glass slab or a mixing pad and

mix thoroughly for 30 sec with agate spatula using folding

method.

8. Convey the material to the cavity

9. Place matrix if required matrix can be cellophane or

mylar strip. Allow cement to set

10. Remove the matrix and remove the excess by using

sharp surgical blade or knife and before it comes in

contact with moisture a protective barrier is applied

either with cavity varnish, petroleum jelly

Final polishing is postponed for 24hours but however modern

GIC’s can be finished and polished immediately after their

restorations.

Matrices in operative Dentistry

• Definition

• Objective

• ideal

requirements

• classification

• Indications of

matrices

Definition:

“A properly shaped piece of metal or

non metal that supports and gives

form to the restoration during its

insertion and hardening”

Objectives:

1. To provide temporary wall of resistance during insertion

and hardening of the material.

2. To displace or retract gingiva and rubber dam

3. To achieve dryness and non-contamination of operating

field.

4. To maintain shape of the restoration till it sets

5. To resist and compensate for dimensional changes that

can occur during setting.

6. To maintain natural contact and contours

7. To promote health of inter dental gingiva by preventing

overhanging restorations.

Ideal Requirements:

1. Should replace the missing wall temporarily

2. Should be rigid, flexible

3. Should have good stability

4. Should be easily applied and removed

5. Should be less cumbersome

6. Should be more comfortable for the patient

7. Should be reusable, sterilisable

8. Inexpensive

9. Should not react or adhere to the restoration material

10. Should be small and handy so that access and visibility

is not affected.

11. Matrix band should extend about 1mm over marginal

ridge.

CLASSIFICATION:

I Based on area of restoration

a) Anterior – Cl III, Cl IV

b) Posterior – extended Cl I and Cl II

II Based on material used.

• Metallic – ex: stainless steel, copper and brass

• Non metallic ex: Celluloid and polyester

available as strips, open faced crowns (semicircular shape),

crown forms (surrounds full tooth)

III Based on method of retention

a) Without mechanical retainers

b) With mechanical retainers

Ex:

A] Black’s matrix and copper band supported by impression

compounds

B] Toffelmire, Ivory no. 1,8, Sequiland

IV Gilmore’s classification:

a) Custom made

Prepared by dentist or assistant suitable size matrix is cut

and impression compound placed in the place of wedge.

b) Mechanical

Toffelmire, sequiland, ivory no. 1 and 8

c) Miscellaneous

T-Band, soldered band, copper band, orthodontic band,

seamless band, blacks matrix.

V Patented (Branded) and Non patented

INDIVIDUAL MATRICES

Ivory No. 1

The band encircles one of posterior proximal surfaces therefore

indicated in unilateral Class II cavities.

Band is attached to the retainer through wedge shaped

projections which engage the tooth thru the embrasures of

unprepared surface.

Ivory No. 8:

Band encircles entire crown therefore indicated for bilateral

class II cavities,

Extended Class I and also for unilateral

Class II in which adjacent tooth is missing.

Tofflemire:

Also called as universal matrix

designed by B.R.Toffelmire.

Best used when 3 surfaces of

posterior teeth have been prepared.

Advantages:

- Convenience

- Placement on tooth buccal and lingual surface but

however lingual approach requires contra angle

design

- Retainer can be easily separated from band without

disturbing restoration.

Available in smaller sizes also so that it can be

comfortably used in deciduous dentition.

Bands available in 2 thickness 0.05 and 0.038mm

Blacks Matrix:

A metallic band is cut so that it will extend only slightly over

buccal and lingual surfaces of the tooth beyond buccal and

lingual extremities of cavity preparation.

This band is tied to the tooth with either a floss or wire at the

corners of gingival ends of band.

Auto matrix:

Retainers not used, designed for any tooth in the arch

regardless of its dimension. Best used in large class II

cavity.

Those replacing one or more cusps and

In pin amalgam restorations.

Advantages:

- Convenience

- Improved visibility due to absence of retainer

- Facial and lingual placement

- Reduced time for application

- Number of teeth can be restored in one visit

Disadvantages:

Expensive

WEDGES

Definition

Classification

Uses

Definition:

Material made up of either wood or synthetic material that is

used along with matrices during insertion and hardening of

plastic restoration material.

It is pointed,

Triangular in cross section

Base of cone is towards interdental papilla.

Classification:

I Based on material used:

- Wooden

- Plastic

II Based on availability

- Preformed

- Custom made – prepared by dentist / assistant

III Based on surface treatment:

- Medicated – coated with astringents

- Non – medicated

IV Based on material used

- Natural

- Synthetic

USES:

- Used along with matrix during insertion and

hardening of restoration material.

- It helps in close adaptability of matrix band to the

tooth thereby preventing restorative material getting

accumulated over the inter dental papilla which is

called overhang of restoration thereby preserving

health of periodontium.

- To immobilize matrix band

- To cause separation

- To retract gingiva and rubber dam

- To arrest bleeding temporarily

SEPERATORS:

- Tooth movement

- Objectives of separation

- Principles of separation

- Methods of separation

TOOTH MOVEMENT:

Act of separating / involved teeth from each other or

bringing them closer to each other or changing their

positions in one or more directions.

OBJECTIVES:

1. To move drifted, tilted and rotated teeth to their

physiologically indicated position to maintain natural

contacts and contours.

2. To close the space between the teeth which is not closed by

restorative methods.

3. To move the teeth in order to improve the health of

periodontium.

4. To move the teeth apically (intrusion) and to move the teeth

incisally (occlusally) called extrusion to make them

restorable.

5. In order to expose the proximal surface to polish proximal

restorations.

6. To change the position of teeth from non-functional

position to a functional position.

7. To detect proximal caries which is not detected by

conventional methods.

8. For easy placement of matrix band

9. To remove foreign bodies collected between teeth which

is not removed by floss, brush or explorer.

Principles:

1. Wedge principle

2. Traction principle

1. Wedge principle:

Separation is achieved by placing pointed wedge shaped

device between the teeth and slowly inducing pressure.

Ex: Elliot’s separator, Wedges.

2. Traction principle:

It is achieved by a mechanical device which engages

proximal surface of teeth to be separated by holding arms

and then separation is achieved.

Ex: Non interfering true separator, Ferrior double bow

separator.

Methods of separation:

Rapid / Immediate Separation

Slow / Delayed Separation

Advantages of Rapid Separation:

Procedures is quick and stable

Disadvantages:

Chance of rupturing Periodontal Ligament fibers and it

will cause pain or soreness.

Examples:

Wedge, Ivory Separator, Elliot’s separator, Non interfering

true separator, Ferrior double bow separator.

Delayed Separation:

Advantages:

1. Less chances of tearing Periodontal ligament fibers

and doesn't cause much pain.

2. No mechanical device required.

3. Separators can be left in place for weeks together.

Disadvantages:

Procedure is time consuming and is not stable.

Examples:

Brass wire/ligature wire, heavy rubber dam material,

rubber elastics, oversized temporaries. Orthodontic

appliances.

MANAGEMENT OF MANAGEMENT OF DEEP CARIOUS DEEP CARIOUS LESIONS LESIONS

Zones of dentinal caries

Effects of caries on pulp dentin organ

Diagnosis of deep carious lesions

Prognosis based on pulp exposure

Treatment.

Zones of Dentinal Caries:Zones of Dentinal Caries:

1. Decayed zone

2. Septic zone

3. Dimineralized zone

4. Transparent zone – zone of dentinal sclerosis

5. Opaque zone

Zones of decay in acute decay.

Zones of decay in chronic decay.

Decayed zone:Decayed zone:

Characterized by –

Complete absence of mineral structure

Organic matrix is completely decomposed

Collagen fibres are lost and if they are present they have lost their cross striations and internal links

Significantly invaded by microorganisms and plaque deposits.

Septic zoneSeptic zone

- Called so because here you find highest population

of microorganisms, even though dentine is

demineralized its frame work structure can be

appreciated.

- Collagen fibers may have normal cross links but

internal links are lost.

- Dentinal tubules are widened and cavitated.

- Remaining mineral structure are deformed and

scattered irregularly.

- Color may range from light yellow to dark reddish

brown

Dimineralized Zone:Dimineralized Zone:

- Important diagnostically and therapeutically

- Dentinal matrix intact

- Collagen fibers normal

- Dentinal tubules normal dimensions

- Repair is taking place in the form of re-mineralization

Transparent Zone:Transparent Zone:

- Also called zone of dentinal sclerosis.

- Looks transparent in ground section but radio opaque in radiographs.

- Here undisturbed repair mechanism is taking place.

- We can find few microorganisms.

- Slightly discoloured and very hard when compared to normal dentine.

Opaque Zone:Opaque Zone:

It is characterized by intratubular fatty degeneration with

lipid deposits being precipitated from fatty degeneration of

the peripheral odontoblastic processes.

The maximum resistance to pulpal penetration occurs with

the arrival of the transparent and demineralized zone.

However, if the septic zone penetrates the pulp chamber, the

P-D organ will be unable to offer any resistance, and will

suffer complete collapse.

Caries can produce 3 types of irritation to Caries can produce 3 types of irritation to

underlying pulp.underlying pulp.

Biological – from microorganisms and their metabolites

Chemical – Acids released

Physico– Mechanical – due to reduced effective depth of pulp

dentine organ.

Severity of these irritation depends on Severity of these irritation depends on

- Type of Decay

- Duration of Decay

- Depth of Involvement

- Number and pathogenecity of microorganisms

- Tooth resistance – depends on thickness of remaining

dentine, permeability and Ca++, F+ content.

Diagnosis and Prognosis of Deep Caries Lesions

1. Pain

2. Radiographs

Indicate

a. The proximity of carious lesions to pulp

chamber and root canal system

b. Any pulpal changes in the form of intra

pulpal and peripulpal calcification

c. The thickening of periodontal ligament with an

intact lamina dura etc.

3. Pulp testing

a. Thermal

b. Electric pulp testing

4. Direct pulp exposure

5. Percussion

6. Type of dentine

Treatment:

Direct

Pulp capping

Indirect

Indirect pulp capping Indirect pulp capping

Clinical Procedure

Decayed and infected zones and the external part of decalcified

zone are excavated using a spoon excavator.

All surrounding walls should be cleared of soft tooth

structure and debris to improve the stability of temporary

restoration.

Suitable capping material either calcium hydroxide or

ZnO liner is placed over the remaining dentine at the deepest

portion.

Then the cavity is sealed with either modified ZnOE Type III

or polycarboxylate cement or sometimes amalgam can be

used.

A radiograph is taken

Patient is recalled after 4-6wks if it is Calcium hydroxide and

6-8 wks if it is ZnO.

When the patient comes back a fresh radiograph is taken and

diagnostic information regarding pain is collected and

compared with pre treatment records.

If signs and symptoms and radiograph findings indicates no

degeneration in the pulp the pulp capping procedure is

considered as a clinical success and we can plan for

permanent restoration.

If repair has not taken place it is better to go in for RCT.

Direct pulp CappingDirect pulp Capping

The tooth can be considered a candidate for DPC

a. There are no signs and symptoms of degeneration in PD

organ.

b. The exposure has small diameter relative to the pulp size

c. There is no hemorrhage from the exposure site, if there is

then blood should immediately coagulate in the form of

small button.

d. Dentine at periphery should be sound.

TREATMENT

All the procedures are same except few things.

1. The tooth to be operated should be isolated from saliva

application of rubber dam is mandatory.

2. Cavity floor and exposed site should be gently washed and

irrigated with sterile water or saline solution.

3. Drying should be done with cotton pellet but never with

air from 3 way syringe patient is called after 6-8wks if it is

Ca OH and 8-9wks if it is ZnO.

Composite Resins:

Definition

Composition

Classification

Polymerization mechanisms

Advantages and Disadvantages

Indications and Contraindications

Clinical procedures for Placement

Definition:

It is a compound with two or more distinctly different materials

the props of which are either superior or intermediate to those of

individual constituents.

Examples:

Natural: Tooth, Enamel and Dentine

Composition:

Organic matrix Major constituents

Inorganic fillers

Coupling agent

Activator or initiator

Inhibritor – Hydroquinone

Colour pigments

Radiopaque fillers – Barium, Strontium, Zirconium

Commonly used matrix:

Are monomers that are aromatic diacrylics examples:

BISGMA – Biphenol Glycidyl dimethacrylate

UEDMA – Urethene Dimethacrylate

TEGDMA – Tri ethylene Glycol Dimethacrylate

Inorganic Fillers are manufactured by grinding glass or quartz to produce particles ranging from 0.1-100um. Silica particles small as 0.04um called as micro fillers can also be produced by option process incorporation of filler particles into the resin matrix will significantly improve physical and therm expansion water sorption polym. Shrinkage ___ reduced whereas compressive, tensile it and modulus of elasticity are increased.

Coupling agents help in binding filler particle to the resin matrix. This not only improves mechanical properties but also provides hydrolytic elasticity i.e it presents water penetrating at matrix filler interface.

Commonly used: Organosilanes

Class

I Based on filler particle size

Conventional – 8-12um

Small particle - 1-5um

Micro filled – 0.04-0.4um

Hybrid - 1um

II Based on polymerization mechanical

Chemically (or self activated)

Light activated

III Based on area of restorations

Anterior

Posterior

Polymerization mechanisms

Chemically

Available as 2 paste systems one or contains benz perox initiator and the other contains tent amine activator.

When thus 2 or brought in contact free radicals are released and polymerization begins.

Light:

Available as single paste system loaded in a syringe. Has a photo initiator mol and amine activator. When it is exposed to the light of correct wavelength photo initiator gets excited reacts with activator, free radicals are released and polymerization starts has also range between 400-500nm. Visible light of the spectrum is used to cure the composites. It is produced by a hallogen bulbwhich is delivered to the required area by a fibre optic disadvatgaes of using U.V light.

1. Limited depth of curing

2. Polymerization shrinkage

3. Occlar hazards

Indications and Contraindications:

1. From Class I to Class IV cavities except high stress bearing

areas like extensive Class II and extended Class I’s

2. Class V cavities in which control of saliva can be achieved.

3. In restoration of developmental defects like enamel

hypoplasia, densein dente microdontia, malpositioned teeth

4. Non carious lesions like cervical abrasions erosions.

5. Treatment of fracture incisal edge

6. Splinting of luxated teeth.

7. Closing diastema (less than 1mm)

8. Veneering of discoloured teeth.

9. Veneering of metallic restorations

10. Core buildings

11. Composite Inlays

12. Repair of old composite restorations

Contraindications:

1. High stress bearing areas like ext class I class V cusp

heights and redges