Dental Cements PDF

7/27/2019 Dental Cements PDF

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DENTALMATERIAL

CEMENTSDr Sara Sarraj


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DENTALCEMENTS

are a classification of dental materials that

are continually used in dentistry. The

American Dental Association and the

International Standards Organization (ISO)

have teamed up to classify dental cements

according to their properties and their

intended uses in dentistry.


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1850s

ZOE

Earl y 1900s

ZP

1900sZinc carboxylate

1972GI

1992

RMGI

Development of dental cements


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CLASSIFICATION OF CEMENTS

Type I: Luting agents that include

permanent and temporary cements.

Type II: Restorative applications.

Type III: Liner or base applications


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LUTING CEMENTS

A material that acts as an adhesive to hold

together the casting to the tooth structure.

Luting agents are designed to be either

permanent or temporary.


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PERMANENT CEMENTS

For the long-term cementation of cast

restorations such as inlays, crowns, bridges,

laminate veneers, and orthodontic fixed

appliances.


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TEMPORARYCEMENTS

Temporary cements are used when the

restoration will have to be removed. Most

commonly, temporary cement is selected for

the placement of provisional coverage.


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TEMPORARY CEMENT

Calcium hydroxide (Dycal)

Zinc oxide eugenol (IRM)

Nonzinc oxide eugenol (Cavit,Tempond)

Zinc polycarboxylate (Duralon) Resins (Neo-Temp)


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BASES & LINERS

Materials used either toprotect the pulp or

aid pulpal recovery or both.

Pulpal irritants:

Heat generated during drilling

Some ingredient of various materials

Heat produced by restorative materials

Forces transmitted to dentine through material

Galvanic Shock Ingress of noxious products and bacteria

through microleakage


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SELECTING BASEORLINER

Should be based on anatomical,

physiological, and biological response

characteristic of the pulp

Also based on the physical and chemical

property of the material considered for use.


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PULPRESPONSE

Is reversibly proportional to the thicknessof remaining dentine.

Cutting odontoblasts extension that havenot been exposed to any irritating episodes

of caries or tooth wear would lead to deathof these cells and their extensionsDeadTracts.(if remaining dentine is 1.5 mm andmore.

If the cutting was atraumatic and coolant

was used,replacement odontoblasts wouldnot be formed hencefoth no reparativedentine would be produced.therefore baseor liners are very important to seal thoseempty tubules.


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GENERAL RULE

Its desirable to have at least 2mm

dimension of bulk between the pulp and

metallic restoration, this bulk may include

remaining dentine, liner ,or base.

Since composite is thermal insulator and

passively inserted, a liner is indicated only

if the excavation is judged to be within 0.5

mm of the pulp,Therefor (BW is important)


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LINERS

Are relatively thin layers ofmaterial(0.5mm) used primarily as barrier

between the restoration and the remaining

dentine following cavity preparation.

Liners should not extend to cavosurface

unless sandwich technique is indicated.


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LINER FUNCTIONS

Protective seal of exposed dentine

Electrical insulation

Thermal insolation ,which depends on

remaining dentine. Pulpal medicament :zinc oxide eugenol

,Ca(OH)2

Pulpal protection against

Residual reactants diffusing out ofrestoration(Chemical)

Oral fluid Leakage(bacterial Influx)


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TYPESOF LINERS

Thin film liners(1-50m)

Solution liners =5m(Varnish)

Suspension Liners= 25m,Ca (OH)2 suspension

Thick Film Liners (cement Liners)= (0.2-

1)mm

Pulpal medication

Thermal protection


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Liners

Thin Film

Solution

5mSuspension

25m

Thick Film

Cementliner

0.2-1mm


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SOLUTION

natural resin dissolved in non-aqueous volatile solvent,(ether, alcohol and acetone ),after application itevaporate leaving resin on the cavity walls

These applied layer filled with pinholes, thereformultiple layers are indicated for an optimum function

Do not dissolve in the oral cavity ,therefor can be used

under: Amalgam, cast gold ,cohesive gold ceramicrestoration

Reduces discoloration by corrosion of amalgam , sinceit acts as dentinal seal.

Should not be used under restoration that have organicsolvent that reduces its value as cavity varnish

(commercial BIS-GMA composite ) dry rapidly

The solvent has anti microbial and antiviral action

Thermal insulating effect


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Cavity Varnish


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CAVITYLINERSUSPENSION

These are suspension ofcalcium hydroxide ,

zinc oxide, and other material in resinous

solution

Used under tooth colored restoration

Have greater physical integrity

Have chemical neutralizing capacity for acids

Dissolve in oral fluids causing severe

microleakage, therefore they should be applied

on dentine only, and do not extend to enamel. Dry slowly

Provides thermal protection due to its

increased thickness,with metallic restoartion


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CALCIUM HYDROXIDE (CH)USES

pulp-capping

a protective barrier between the dentin

pulp complex and acid-containing cements

and restorative materials, cements, and

other base materials.

It will not inhibit the polymerization of

acrylic and composite restorations

Improved physical properties with higher

compressive strength and lower solubility.


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CA(OH) ADAVANTAGES

Proven Clinical Efficacy. Shown to protectthe pulp and promote the formation ofReparative dentin

Fast Setting

High Early Strength Low Water Solubility

Available in Dentin or Ivory Shade. - allowsfor more natural looking esthetic

restorations. Excellent Handling

Easy to place, with ability to flow whereneeded while it stays in place whennecessary


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CA(OH)2 SUPPLY

Chemically cured forms Dycal, DENTSPLY

Caulk)

light-cured forms :Prisma VLC Dycal,

DENTSPLY CaulkChemically

Chemically curedlight-cured


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CLINICALIMPLICATIONS

Serves as an irritant stimulating the

formation of reparative dentin; and

Second, the therapeutic affect of CH may

be due to its ability to extract growth

factors from the dentin matrix. The result is

the formation of a dentin bridge, which

allows pulpal repair.


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WHICHISTHEBESTLINER?

The ability of calcium hydroxide tostimulate the formation of reparativedentine when it is in contact with pulpaltissue makes the material of choice for very

deep excavation. Liners and bases in very deep excavation

should be applied without pressure.

Ca(OH) should be 1mm thickness nearpotential or actual exposure .

In these instances the base should be usedin putty-like consistency ,so that less freeacid ,and elimination of the rotary andpressure.


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CAVITY BASES

Those cements commonly used in thicker

dimensions beneath permanent

restorations to provide for mechanical,

chemical, thermal protection of the pulp.

Bases can be considered as restorative

substitutes for the dentin that was removed

by caries and/or the cavity preparation.


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CAVITYBASES

Calcium Hydroxide Ca(OH)2

Zinc-Oxide Eugenol ZOE

Zinc Phosphate

Polycarboxylate Zin-Silico-Phosphate

Glass Ionemer

Mineral trioxide aggregate (MTA)

Ca(OH)2+ZOE+MTA =Intermediary Bases


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CALCIUM HYDROXIDE

Has pH 11-13 therefore it can be used in

deep cavity to neutralize the acids

produced by bacteria,and as sub-base to

neutralize the irritating acidic components

of base or restoartive material

Its supplied in two forms:

Powder

Paste (Dycal) :chemically set, or light cured


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ZINC-OXIDE EUGENOL

Zinc-Oxide has pharmacological action onpulpal tissue,while Eugenol has topicalanesthetic property(obtunding effect)

As Intermediate restorative material provide anexcellent seal of the cavity preparation

ability of ZOE to reduce postoperativesensitivity

Has long setting time:The clinician should allowapproximately 24 hours to pass prior to placing

amalgam above a ZOE base. Low compressive strength(brittle)

Eugenol interfers with polymerization of resinmaterial therefore can,t be used beneath,andsubstituted with Ca(OH)2.


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REINFORCED ZOE

chemical composition of ZOE is typically:

Zinc oxide, ~69.0%

White rosin, ~29.3%

Zinc acetate, ~1.0% (improves strength) Zinc stearate, ~0.7% (acts as accelerator)

Liquid (Eugenol, ~85%, Olive oil ~15%)


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ZINC-PHOSPHATE CEMENT

Powder:Zinc-Oxide

Liquid Phosphoric acid

Electrical and thermal insulator

Stay acidic after application ,therefore should beabove Ca(OH)2 or ZOE in deep cavity

Has low linear of coefficient of thermal expansion

Compressive strength 100mpa

The material is acidic when placed (pH ofapproximately 3.5), but rises to a pH of 6.9 after

a week.


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CLINICALCONSIDERATION

packages of ZP contain 20% more liquid

than is necessary to combine with the

powder. This is because some of the liquid

will evaporate during use. This

specification applies to zinc phosphate, zincpolycarboxylate, and GI together since they

all are water-based. This is important for

the clinician to consider. Since the water

can evaporate, these materials can becomeviscous, leading to difficulty in seating

crowns. Furthermore, loss of water will

result in a decrease in the pH of the liquid,

making the cement less biocompatible


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ZINCPOLYCARBOXYLATE CEMENT

Powder :Zinc Oxide

Liquid:Polyacrylic acid

As electrical and thermal insualtor

Has low linear of coeffecient of thermalexpansion

Has adhesive bond to dentine only


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ZPC(DURELON )

Zinc polycarboxylate adheres to the tooth

via an interaction between the carboxylic

acid and the calcium in the dentin

Polyacrylic acid has a very low pH (1.7), but

the pH approaches neutrality upon mixingwith the powder

the relatively large size of the polyacrylic

acid molecule and/or its ability to combine

with protein prevents it from diffusing intodentin tubules


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GLASS IONOMER

Powder: ion leachable glasses

Liquid;Copolymer of polyacrylic acids

Has thermal and electrical insulation effect

Compressive strength 120MPa Has adhesive bond to enamel and dentine


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RESINMODIFIED GLASS

IONOMER,RMGI(VITREBOND)

first is their ability to ionically bond to

tooth structure (between the carboxylate

groups in the GI and the calcium ions in the

enamel and dentin)

They release fluoride

Reduction in the consequences of micro

leakage

antimicrobial properties

ability to adhere to and seal the dentin


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RMGI

GIs should not be used as pulp-capping

agents. In a clinical study, GI was found in

the pulp chamber, which triggered a

persistent inflammatory response and

appeared to prevent the formation of dentinbridges.

They are extremely sensitive to moisture

when GI comes in contact with water, there is a

decrease in its physical properties. In addition, resin-modified GIs expand after

coming in contact with water.


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PRECAUTION..

caution is needed because certain materials

are not compatible with each other. For

example, Yang and Chan demonstrated that

varnishes can reduce the surface hardness

ofglass ionomers.


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ZINC-SILICO PHOSPHATE CEMENT

Powder: Acid soluble silicate

+Zinc+magnisium

Liquid:Phosphoric acids

Translucent and superior to the opaque ZP

cement

Has flouride release ,this has caries

inhibition effect

Has the same clinical application of ZP

High stength and translucency

=cementation of ceramic restoration, but

has been replaced by GI and resin cements


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CLINICAL CONSIDERATION

Selection Base or Liner depends on:

Thickness of remaining dentine

Adhesive property of both liner and base

Type of restoration placed aboveWhen Dentine >2mm ,no need for pulpal

protection ,and varnish is used against

microleakage at the intersurface.

When remaining dentine is < 2mm ,Ca(OH),ZOE as liner or base .Eugenol acts as

seadtive to the pulp. ZOE contraindicated

under resin restoration since it counteracts

polymeralization of resin


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When remaining dentine is 0.5-1mm or near

the pulp, use 1mm layer of Ca(OH)2 or MTA

to encourage reparative dentine.

Adhesive cement liners are used after

removal of extensive carious dentine, GIbonds to Enamel and dentine while

polycarboxylate bonds to dentine only


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RESIN CEMENT

Bond strength > Zinc phosphate 10 times

Retention Reinforced ceramic - base Crown

Adhesive system (micromechanical bond-tooth)

(chemical bond-porcelain,metal)

Low solubility

leakage


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CHARACTERISTICOFTEMPORARY

CEMENTS

Simple to use

Easy to remove to allow final placements of

defenitive restorartion

Do not interfere with setting of defenitive

material

Durable enough for few weeks

Biocompatible

Acceptably aesthetic


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ZINC-OXIDEEUGENOL

Eugenol,

H2O

acetic acid,

calcium chloride.

Zinc Oxide

Magnesium Oxide

Silica

Liquid Poweder


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MODIFIED ZOE

Addition of Zinc Acetate to powder setting time to 5min

Addition of 10% hydrogenated resin to

powder strength (resin-bonded ZOE)Addition of EBA (Ethoxy benzoic acid) 62%

to liquid strength


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VARIABLESAFFECTINGTHECEMENT

The thicker the mix the greater the

srtength

Heat setting time therefore cooled slab isadvisable

Dip the mixing instrument with powder to

stop sticking of cement to instrument

during placement

When luting, apply cement to restoartion

before tooth.


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TYPESOF ZINC-OXIDE EUGENOL

Lacks strength and

long-term

durability and isused for temporary

cementation of

provisional

coverage.

Type I

Has reinforcing

agents added and is

used for thepermanent

cementation of cast

restorations or

appliances.

Type II


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ZINC-OXIDE EUGENOL

Temporary filling

and thermal

insulation (base).

Cavity liners

TypeIII TypeIV


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SUPPLYOF ZINC-OXIDE EUGENOL

Mixed on an

oil-resistant paper

pad. Mixing time ranges

from 30 to 60

seconds.

Setting time in themouth ranges from

3 to 5 minutes.

Supplied as a

two-paste system as

temporary cement. Pastes are

dispensed in equal

lengths on a paper

pad and mixed.

Liquid/Powder Paste


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Liquid/Powder Paste


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FASTSETTING ZOE


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MIXING ZOE

3scops Powder+4

drops of liquids


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VARIABLES AFFECTING CEMENTS

Mixing time

Make sure to follow the manufactures

directions for the mixing time, working

time, and delivery time.


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LUTING CEMENTS REQUIREMENTS

Long working time

Adhere well to both tooth structure and

cast alloys

Non toxic to the pulp

Adequate strength properties

Be compressible into thin layer

Low viscosity

Low solubility Good working setting characteristics

Excess could be easily removed


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ZINCPHOSPHATE

Powder

zinc oxide

Magnesium oxide

Liquid

phosphoric acid


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CLINICAL CONSIDEARTION

ZP release irritants while setting, therefore

dentine should be protected with varnish

Cements that are able to bond to dentine should

have direct contact with dentine, therefore

varnish should not be used under GI orpolycarboxylate cement or composite or ceramic

restoration.


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CAVIT

suitable means of provisionally sealing

prepared cavities

For sealing in medicinal inserts. They

serve as dressings for the dentine surface,

so protecting the periodontium and pulpagainst harmful influences.

In the case of root canal treatment, they

also prevent infection of the peri-apical

tissue caused by saliva.

C


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CAVIT Born 1947Temporary filling of occlusion-loaded

restorations

Has three types Cavit W: its increased adhesion to the hard tooth

substance and reduced final hardness, is specially designedfor use in endodontic treatment.

Cavit G:is ideal for inlay preparations, since it is easilyand cleanly removed without using rotary instruments.

Cavit LC (Light Cures): is a hybrid composite fortemporary restoration of cavities. The newer version of all . Release Fluoride

Minimal Shrinkage when polymerizes provides highmarginal integrity which prevents ingress of micro-organisms into the cavity

High mechanical strength

Chemical stability in the oral environment Easy handling

Easy removal

Aesthetics

Economy


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CAVIT LC

CAVIT LC is useful for sealing implantscrewholes and as a lining for pre-formed

temporary crowns and bridges.

Temporary sealing compound for

temporary restoration of cavities.


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CAVIT G, COLTOSOL

Temporary restoration of cavities for short timeperiods (1-2 weeks)

Contraindicated incases of: Allergy to components

Long temporization requirements Temporary filling of cavities which include multiple areas

and extend up to or under the gingiva (subgingival)

Advantages: Non eugenol formulation offers non irritating properties

Easy to use

packs and carves with no stringiness.

self-curing (light cure preparations are available) underhumidity

Simple to apply with filling instrument

Quick and void-free curing in a moist environment


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MINERALTRIOXIDEAGGREGATE (MTA)

root-end filling,

perforation repair,

vital pulp therapy,

apical barrier formation for teeth with necrotic

pulps and open apexes.

Hydroxyapatite crystals form over MTA when it

comes in contact with tissue fluid. This can act as

a nidus for the formation of calcified structuresafter the use of this material in endodontic

treatments


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MTA

The compressive strength of MTA increasedwith time in presence of moisture.

Radiopacity is given by Bismuth Oxide.

MTA is less radiopaque than Super EBA, IRM,

amalgam, and conventional gutta-percha, but in thesame range as zinc oxideeugenol-based root canal

sealers.

better marginal adaptation to the root end

cavity wall than other materials, and thus

preventing microleakage. has antibacterial effects against Enterococcus

faecalis and Streptococcus sanguis.

Biocompatible


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DIRECT PULP CAPPING

The formation, quality, and thickness of acalcified bridge.

presence of inflammatory cells,

preservation of the pulp are considered

evaluation criteria after vital pulp therapy


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CHEMICAL COMPOSITIONOF MTA

1.Dicalcium silicate2.Tricalcium silicate

3.Tricalcium aluminate

4.Gypsum

5.Tetracalcium aluminoferrite

6.Bismuth oxide

7.Manganese

8.Strontium

9.Chromophores (iron oxide)

10.Aluminium11.Potassium


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MTA DRAWBACKS

long setting time

High cost

potential of discoloration


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RESINCEMENTS

They are very versatile (generally being ofhigh compressive and tensile strength.

possess low solubility

different viscosities and different shades

When resins are used as a cavity liner, it is

important to remember that it is the dentin

bonding agent (examples: Clearfil SE Bond,

Kuraray America; Excite, Ivoclar Vivadent)

that comes into contact with the dentin


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Can,t be used for direct pulp cap(likeGI)since they do not promote the formationof dentinal bridge,however they elicit apersistent mild inflammatory pulpalresponse

adhesives placed below amalgamrestorations reduce microleakage,thussupporting the current trend toward thispractice of using resin as a liner.

Lining cavities with copal varnish is fasterand less technique-sensitive than usingadhesive resin, and resins cost more andhave a limited shelf life.


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RESINASLINER

It has been observedthat some adhesives

do not bond well to

dentin in deep cavity

preparations. Thismakes them more

susceptible to

polymerization

shrinkage stress that

develops in deep

cavities.


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TOOVERCOMESHRINKAGEASSOCIATED

WITHRESINRESTOARTIONINDEEPCAVITY

Sadwish Technique:inwhich the liningmaterials(Vitrebond)are brought to thecavosurface margin

under compositerestoartion.

Advantage:Release Fand the releasedflouride can be

externally replaced light-cured GI have

been shown to provide abetter seal


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CONCLUSION

In terms of pulpal health, it is more beneficialto conserve tooth structure when possible than

to remove that same tooth structure and

replace it with a restorative material,

Studies demonstrated that a 0.5-mm thicknessof remaining dentin reduces toxicity of a

material by 75%, and if that thickness is

increased to 1.0 mm, a reduction of 91% is seen.

An intact smear layer helps occlude the

dentinal tubules and therefore provides abarrier to bacterial invasion,and liner is

required to coat this fragile layer to reduce

microleakage.


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GOOD LUCK

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