ROOT CANAL SEALERS

ByDR. LENIN BABU .T

CONTENTS

1. Introduction 2. History 3. Functions of sealer4. Ideal requirements of sealer5. Classification6. Gutta-percha-based root canal sealers7. Zinc oxide-eugenol-based root canal sealers8. Calcium hydroxide-based root canal sealers

• 9. Formaldehyde-based root canal sealers• 10. Glass ionomer-based root canal sealers• 11. Resin-based root canal sealers• 12. Silicon-based root canal sealers• 13. New sealers• 14. Mixing of sealer• 15. Placement of sealer• 16. Sealer efficacy• 17. Tissue Tolerance• 18. Conclusion• 19. References

INTRODUCTION

• The use of sealer during root canal obturation enhances the possible attainment of an impervious seal and serves as filler for canal irregularities and minor discrepancies between the root canal and core filling material

HISTORY

• 1931 – ZOE cement was developed as a root canal sealer by Rickert.

• 1936 – Grossman’s non-staining ZOE formula appeared as a sealer that afforded more working time.

• 1952 – Biocalex –Bernord• 1955 –Scheufele introduced resin based

Diaket as a sealer.

• 1955 – Wach cement – Dr Edward Wach.• 1960 – Wichterle and Lim introduced a Plastic

Material Hydron.• 1961 – Tubliseal was introduced with a slight

modification to Rickert’s formula to eliminate staining properties.

• 1965 – Nyborg and Tullin gave a formula of kloroperch.

• 1973 – N2 - Sargenti • 1976 – Pittford recommended endodontic

glass ionomer Ketac-Endo as a root canal sealers.

FUNCTIONS OF A SEALER

Cementing the core Germicidal Fills the discrepancies between the filling material

and the dentin wall. Form a bond between the filling material and the

dentin wallsRadiopacity which discloses the presence of

auxiliary canals, resorptive areas, root fractures and the shape of the apical foramen.

Lubricant which aids in the seating of GP

IDEAL REQUIREMENTS

The ideal root canal cement should (Grossman 1940)provide an excellent seal when set should be tacky when mixed to provide adequate

adhesion among it , the canal walls and the filling material

be radiopaque so that it can be visualized in the radiograph

be non stainingparticles of powder should be very fine so that they

can mix easily with the liquidbe dimensionally stable

be easily mixed and introduced into the canal be easily removed when necessary insoluble to tissue fluids bactericidal or discourage bacterial growth slow setting to ensure sufficient working time tissue tolerant , that is non irritating to the

periradicular tissues should not provoke an immune response in

periradicular tissues non mutagenic nor carcinogenic

CLASSIFICATION

1. Based on their compositiona. Eugenol basedb. Non-Eugenol basedc. Medicated

• Eugenol based group is further sub-divided into a. Silver containing – Kerr sealer, Procosol b. Silver free – Procosol non-staining, Grossman’s sealer, Tubliseal, Wach’s paste.

• Non-Eugenol sealers: a. Diaketb. AH-26c. Kloroperka and

Eucapercha d. Nogenole. Hydronf. Endofilg. Glass Ionomerh. Calcium phosphatei. Cyanoacrylates andj. Polycarboxylates

• Medicated:N2,

SPAD, Iodoform paste DiaketRieblers pasteCa(OH)2 paste Mynol cement and Endomethasone.

2. According to Grossman:a. Zinc oxide cementb. Calcium hydroxide cementc. Paraformaldehyde cementd. Pastes

3. According to Clark:a. Absorbable:

Kerr sealer (Rickert)Grossman’s sealerRoth root canal cementTubliseal, Tubliseal EWT,Sealapex

b. Non-AbsorbableDiaket AH PlusKetac Endo

4. According to Ingle:CementsPastesPlastics

5. According to Harty:a. Zinc Oxide eugenol basedb. Resin basedc. Gutta percha basedd. Dentin adhesive materialse. Medicated cements

6. Nicholus classified the most commonly used sealers according to alphabetical order.

a. AH-26b. Diaket c. Endomethasoned. Grossman’s cemente. Kerr Root canal systemf. Kerr Tublisealg. Kloroperchah. N2i. Wach’s cement

GUTTA-PERCHA BASED SEALERS

1. Chlorpercha 2. Kloroperka N-O3. Eucapercha

Chloropercha(Moyco)Mixing white gutta percha 9% with

chloroform 91% Premixed sealerHas no adhesive properties Kloropercha (Nygard –Ostby)Powder liquid mixturePowder : Canada balsam -19.6

Resin – 11.8%Gutta percha – 19.6%Zinc oxide – 49%Liquid:Chloroform -100 % Zinc oxide is added to reduce shrinkage, also

increases radiopacity Shrinkage of 7.5% is seen Chloroform evaporates leading to loss of volume

and “dropping “ of filling into the periapical area Chloroform is toxic

Eucapercha: By Buckley Eucalyptol is used Takes longer than chloroform Has antibacterial and anti-inflammatory action Segment of gutta percha held over alcohol lamp

for 20 to 30 sec Eucapercha dissolves and turns into a cloudy mass Indications: ledge formation, perforation, unusual

curvatures, in cases in which the apical foramen cannot be successfully sealed

• Disadvantages:Difficult to avoid overfilling of the canal If extruded, acts as an irritant initially.

ZINC OXIDE-EUGENOL BASED SEALERS

1. Kerr Pulp Canal Sealer2. Procosol – Silver cement 3. Procosol – Silver free (Non-staining)4. Tubliseal5. Grossman’s sealer6. Wach’s cement7. Zinc Oxide-Non-Eugenol-based Sealer

(NOGENOL).

Kerr Pulp Canal Sealer

Developed in 1931 as Rickert’s sealerDeveloped as an alternative to Gutta-perchaWas introduced as Kerr pulp canal sealer in

1951.Powder zinc oxide powder- 41.21 parts precipitated silver – 30 parts White resin – 16 parts thymol iodide- 12.79 partsLiquid: oil of cloves-78 parts Canada balsam – 22 parts

Indications: Vertical condensation of warm gutta

percha when large bulk of sealer is needed

when lateral canals are anticipated, for silverpoints.

Contraindications has staining qualities , needs to be

removed from crown.

Advantage: great bulk , so can be pushed into voids and irregularities

Disadvantage: presence of silver makes the sealer extremely staining if material enters the tubules or enters the crown

Properties: Excellent lubrication. Working time of 30 min L:P ratio : 1:1 Germicidal action Mixed with a heavy spatula until homogeneity is

obtained Because of the presence of silver, some granular

appearance remains even after spatulation.

Procosol –Silver Cement (Grossman 1936)

-Rapid setting of Rickerts formula lead to development of Grossman’s formula in 1936, known as ProcoSol radiopaque silver cement.

Powder: Zinc oxide -45 partsSilver (precipitated) -17 partsHydrogenated resin – 36 partsMagnesium oxide -2 partsLiquid:Eugenol -90 partsCanada Balsam -10 parts

- Precipitated silver lead to staining , lead to the development of ProcoSol nonstaining root canal cement

Powder:Zinc oxide , reagent 40 partsStaybelite resin 30partsBismuth subcarbonate 15 partsBarium sulfate 15 partsSodium borate, anhydrate 1 part

(extends the setting time) LiquidEugenol or oil of pimenta leaf

Advantages: plasticity , slow setting time in the absence of moisture, good sealing potential because of the small volumetric change on setting

Cement hardens in app 2 hours at 37 degree and 100% relative humidity

Setting time in canal is lessBegins to set in root canal within 10 to 30

min because of the moisture present in dentin

Tubliseal (Kerr, 1961)

Base:Zinc oxide – 57.4%Oleo resins- 21.25%Bismuth trioxide – 7.5%Oils – 7.5%Thymol iodide – 3.75%Modifier – 2.6% Catalyst:EugenolPolymerized resinAnnidalin

Indications: When extreme lubrication is needed, as in

slightly short master cone, before apical surgery. Contraindications: Irritating to periapical tissues, not to be used if

overfill probable with normal periapical tissue. Sets very rapidly when wet

Packaging: two tubes , accelerator and base Mixing: mix equal lengths to creamy consistency

Properties:Easy to mixNon stainingAllows maximal condensation and packing Is white in color with good contrastGood lubricating qualities Advantages: ease of preparationHigh rate of flow, thinner film

Disadvantage:Irritating to periapical tissues,

causing considerable periapical sensitivity when used on teeth where pulp was vital and the periapical tissue normal before treatment.

Rapid set in the presence of moisture

Grossman’s cement

• Introduced by Grossman 1974.• Most widely used sealer.• Powder and liquid should be mixed to a smooth

creamy consistency.• Powder:

Zinc Oxide – 42%Stabelite Resin - 27% Bismuth subcarbonate – 15% Barium sulphate – 15% Sodium borate (anhydrous) – 1%

• Liquid:Eugenol – 100%

• Test to Check the consistencya. String out test: should string out at least an inch before breaking (when cement spatula is lifted from the mix).

b. Drop test: suspended mix should cling to the inverted spatula blade for 10-15 seconds before dropping.

• Properties:Good sealing potential because of small

volumetric change on setting.Resorbs gradually if extruded apically.Reversible inhibitory effect on nerve tissue.

• Disadvantages: It is a weak unstable material.Decomposed by water through a continuous loss of eugenol. Not a good choice for retrofillings.

Wach’s cement (1925 – 1955)

Powder: Zinc oxide 10g bismuth subnitrate -3.5 g bismuth subiodide -0.3 g magnesium oxide – 0.5g tri calcium phosphate-2 gLiquid: Canada balsam 20 ml oil of cloves- 6ml, eucalyptol 0.5 ml beechwood creosote -0.5 ml.

Indications: all lateral condensation methods, especially when chance of overfilling is present Adhesive , good for lateral compaction in small canals, softens gutta percha ,

Contraindication: when heavy lubrication is needed , as with short master cone.

Advantage: smooth consistency without a heavy body

Canada balsam makes the sealer tackyDisadvantage: odor of liquid

Properties: medium working time, less lubricating qualities Minimal periapical sensitivity Increasing the thickness of sealer lessens its

lubricating effect, thus when an overfilling appears possible , a maximal degree of thickness should be employed.

Useful in small curved canals of minimal caliber,Has light body , so does not deflect the small

master gutta percha cones used to fill these canals.

Its is very sticky , due to Canada balsam, so paste will remain on reamer until its spun off in the apical portion,

Nogenol

Base is zinc oxide , barium sulfate , vegetable oil

Accelerator is : hydrogenated rosin, methyl abietate, lauric acid, chlorothymol, salicyclic

acid Developed to overcome the irritating quality

of eugenolDid not set hard, but remained rubbery ,

water sorption was high.More biocompatible than ZOE cements.

CALCIUM HYDROXIDE-BASED SEALERS

1. Sealapex2. CRCS3. Apexit4. Calcium Phosphate-based Sealers

(Apetite Sealers)5. Bioseal6. Capseal I and II

Sealapex

• It is a zinc oxide-based calcium hydroxide root canal sealer containing polymeric resin.

• Available as a two-paste system.• Base:

Calcium hydroxide (25%)Zinc oxideButyl benzeneSulphonamide Zinc stearate

• Catalyst:Barium sulphateTitanium dioxideIsobutyl salicylateAerosil R 972.

• Available in Two forms:Sealapex regularSealapex EWT

• Properties:Has good therapeutic effectBiocompatibleExtruded material resorbs in four months.Osteogenic potential.

• Disadvantages:Takes a long time to set (3 weeks in 100% humidity)Absorbs more water and expands while settingHas poor cohesive strength

CRCS• It is the first sealer of the Ca(OH)2 group.• It is basically a Zinc oxide eugenol/Eucalyptol sealer to which

Ca(OH)2 has been added for its osteogenic effect.Powder:Calcium Hydroxide Zinc oxideBismuth dioxideBarium sulfate

Liquid:EugenolEucalyptol

• Properties:Takes 3 days to set fully in dry/humid environmentsHas good therpeutic effect Quite stable, shows very little water resorptionCauses chronic inflammation if extruded

periapicallyEasily disintegrates in the tissue (resorbs)

• Disadvantages:Has poor cohesive strength.

Apexit

• Available as a Two-Paste System: Base:Calcium hydroxide : 31.9%Zinc oxide : 5.5%Calcium oxide : 5.6%Silicon oxide : 8.1%Zinc stearate : 2.3%Hydrogenized colophony : 31.5%Tricalcium phosphate :4.1%Polydemethylsiloxane :2.5%

Activator:Trimethyl hexanedioldisalicylate : 25%Bismuth carbonate basic : 18.2%Bismuth oxide : 18.2%Silicon dioxide :15%1,3-Butanedioldisalicylate :11.4%Hydrogenized colophony :5.4%Tricalcium phosphate :5.%Zinc stearate :1.4%

• Properties:Seals better than sealapexGood biocompatibility.

Calcium Phosphate-bases Sealers ( Apatite Sealers)

• Apatite Root Sealer Type I:Powder

Alpha-tricalcium phosphateHydroxyapatite

LiquidPolyacrylic acidWater

• Apatite Root Sealer Type II:Powder

Alpha-Tricalcium phosphateHydroxyapatiteIodoform

LiquidPolyacrylic acidWater

• Properties:Has some amount of inflammation due to the presence of polyacrylic acid and is more severe with ARS II.

Capseal I and II

• Is biocompatiblePowder

Tetracalcium phosphate (basic)Dicalcium dihydrate (acidic)Portland cementZirconium oxide Others

LiquidSodium phosphate solution (pH 7.4)

• Capseal II – White Portland Cement

FORMALDEHDYE-CONTAINING SEALERS:

1. N22. Endomethasone3. SPAD4. Riebler’s paste

N2 (Sargenti 1973)

PowderZinc oxide - 69%Lead tetroxide-12%Paraformaldehyde 6.5%Bismuth subcarbonate 5%Bismuth subnitrate 2%Titanium dioxide 2%Barium sulphate 2%Hydrocortisone 1.2%Prednisolone 0.21%Phenylmercuric borate 0.09%

• LiquidEugenolIntroduced by Sargenti and Ritcher in 1954.American counterpart RC2B.

Contains lead and mercury which are major systemic poisons

Loses volume when exposed to fluid due to presence of paraformaldehyde

Coagulation necrosis in 3 days time, which can’t undergo repair due to formaldehyde impregnation

Irreversibly affects nerve endings in tissue area, thereby masking inflammation process

Paraformaldehyde is included to obtain release of formaldehyde gas for antiseptic and fixative action

Corticosteriods for suppressing inflammatory reaction

lead as an oxide, which by increasing the opacity gives the illusion of the materials compactness, and contribute to the extreme hardness and slow solubility of the final set.

• In recent formulae, lead oxide and organic mercury are missing because of toxicity.

Endomethasone

• Formulation very similar to N2• Pink antiseptic powder mixed with eugenol.PowderDi –iodothymol 25 gTrioxymethylene (paraformaldehyde) -2.2gHydrocortisone acetate – 1 gDexamethasone 0.01gExcipient 71.79 g

Liquid• Eugenol

SPAD

• it’s a resorcinol –formaldehyde resin • supplied as powder and two liquids Powder:• Zinc oxide – 72.9%• Barium sulphate -13%• Titanium dioxide – 6.3%• Paraformaldehyde – 4.7%• Hydrocortisone acetate- 2%• Calcium hydroxide – 0.94%• Phenyl mercuric borate 0.16%

Liquid (clear)• Formaldehyde 87%• Glycerin 13%Liquid LD (red)• Glycerin 55%• Resorcinol 25%• Hydrochloric acid 20%

• Equal parts of the two liquids mixed with powder.• Essential reaction to form resin is between

resorcinol and formaldehyde

An acidic pH is needed for this reaction, this is provided by HCl.

Large amount of zinc oxide is to control the pH and so prolong the setting time

inclusion of HCl is not harmful ,pH at the time of mixing was 5.2 and rose to 6.2 after 2 hrs , due to the neutralizing effects of Zinc oxide

setting time of SPAD is 24 hrs, during this period there is free unreacted formaldehyde,.

solubility of SPAD is 4 % after 24 hrs.

Tissue response:Pulpal necrosis, periapical inflammations

and necrosis, Toxicologic studies:Systemic absorption of lead and

paraformaldehydeHeavy metal ions- disseminated throughout

the body Irrevisible damage to nerve endings -

paraformaldehyde

• Used as a sealer or to completely obturate the canal.

• Recommended for pulpotomies in deciduous teeth.

• Biocompatible• Radiopaque.

Riebler’s paste

• Resin type of sealer containing formaldehyde.PowderZinc oxideFormaldehydeBarium sulfatePhenol

Liquid:FormaldehydeSulfuric acidAmmonia Glycerin

Glass-Ionomer Sealers

1. Ketac-Endo

Ketac-Endo

• Pitt Ford recommended the use of GIC.Properties:• Film thickness – 22 micro meter• Exhibits adequate working and setting time• Less technique sensitive• No shrinkage upon setting• Radiopaque• Chemically adheres to the dentin (makes the root

resistant to fracture).

• Provides a stable apical seal• Polyacrylic acid may chelate with zinc oxide of

gutta-percha cones by forming a bridge (zinc polyacrylate)

• Good biocompatibility in bones and tissues.

Disadvantages:• Extruded sealer is highly resistant to

resorption by tissue fluids and becomes an implant in the periapical tissues

• Minimal antimicrobial activity• Difficult to remove during re-treatment.

RESIN-BASED SEALERS

1. Ketac-based Resin sealers:• Diaket

2. Epoxy-based Resin sealers:• AH-26• AH-Plus• AH-Plus jet Root canal sealer

3. Methacrylate-based Sealers:• Endo-Rez• Fibrefill Root Canal Sealer• Epiphany Root Canal Sealer

Ketac-based Resin Sealers

• Diaket:Introduced by Schmidt in 1951Powder:Zinc oxideBismuth phosphateLiquid:Dihydroxy dichlorophenylmethanePropionylacetophenoneTriethanolamineCaproic acidCopolymers of vinyl acetate, vinyl chloride, vinyl

isobutylether

Polyketone compound with vinyl polymers that mixed with zinc oxide and bismuth phosphate forms a adhesive sealer

Sets quickly in root canalVolume stability is goodSolubility is low Powder liquid ratio : 1:2Gross overfilling caused modification of apical

cementum and alveolar boneHas a tendency to be encapasulated by

fibrous capsuleAdheres well to dentin

Epoxy-based Resin Sealers

• AH-26:-Schroeder , 1957Was initially used in Europe to completely fill

the canal but now used extensively as a sealer.

Powder:Silver powder – 10%Bismuth oxide 60%Hexamethylene tetramine -25%Titanium oxide – 5%

Liquid:Bisphenoldiglyicdyl ether -100%Packaging: Powder and liquidMixing: mixed to a creamy consistencyProperties:Good flowSeals well to dentin wallsSufficient working timeToxicity in the first 24 hrs due to release of

formaldehyde

Strong adhesive & contracts on hardeningSchroder – well tolerated by tissues. Tends

to disintegrate into fine granules which are phagocytosed

Hardens slowly at body temperature in 36 to 48 hrs

Its not sensitive to moisture, will set under water.

Will not set if hydrogen peroxide is present

Sets slowly in 24 to 36 hrsMixed cement should be warmed on

glass slab over alcohol flame to make it less viscous

Sold world wide as therma sealDisadvantages:Allergenic /mutagenic potentialpossible formaldehyde release silver containing

AH-Plus

• Available as a paste-paste form• Epoxide paste:

DiepoxideCalcium tungstateZirconium oxideAerosilPigment

• Amine Paste1-Adamantane amineN,N’-dibenzyl-5-oxa-nonandiamine-1,9

TCD-diamineCalcium tungstateZirconium oxideAerosilSilicon oil

Added new amines to maintain the natural color of tooth

Working time of 4 hrs , setting time of 8 hrs, half the film thickness, and half the solubility of regular AH26.

Non mutagenic , no release of formaldehyde, radiopaque, can be used with all techniques

AH-Plus Jet Root Canal Sealer

• Greater efficiency with no mixing required• It is preloaded, double-barrel syringe, which

provides controlled homogenous mixing of both pastes directly on the mixing pad or by using its adjustable intraoral tip for precision placement.

• A superior seal is achieved with excellent radiopacity and low shrinkage.

Methacrylate-based Sealers

Endo-Rez:• Is based on urethane dimethacrylate• Hydropohilic, chemical set material• Supplied in a TwoSpense mixing and delivery syringe.• Composition:

Zinc oxide Barium sulphate Resins

PigmentsIn a matrix of urethane

dimethacrylate resin

Properties:• Has radiopacity similar to gutta-percha cones• Can be used along with dentin bonding agents• Excellent sealing properties• Good adaptation to the root canal walls in the

presence of moisture• Effective penetration of material into the

dentinal tubules

• Remains soft and plastic for a long period of time.

• Improves performance even in the presence of moisture.

Disadvantages:• Has good coronal and middle third sealing

ability but poor apical third sealing• Has a shelf life on only 18 months.

Fibrefill Root Canal Sealer• Composition resembles that of dentin-bonding agents.Composition:• Mixture of resins• Treated barium borosilicate glasses• Barium sulphate• Silica• Calcium hydroxide• Calcium phosphates• Stabilizers• Pigments • Benzoyl peroxideUsed in combination with a self-cured primer.

Epiphany Root Canal Sealer

• Is a dual-curing, hydrophilic resin sealer• Used with Resilon core materials• Dispensed from a double barrel, automix

syringeease of useaccurate mixing

• 17% EDTA is used to remove the smear layer followed by rinsing with either 2% chlorhexidine/saline (NaOCl is not used as it disrupts the dentin bond)

• Composition: Resin Core materialResin matrix

Mixture of BisGMAEthoxylated BisGMAUDMAHydrophilic dysfunctional

methacrylates

• Fillers (70% by weight)Calcium hydroxideBarium sulphateBarium glass Silica

• Composition: Epiphany PrimerSulphonic acid-terminated functional monomer HEMA

WaterPolymerization

initiator

Properties of Resilon:• Bonds to both the epiphany primer and resilon

obturating material• Can be light cured for an immediate coronal seal• Self-cures apically in 25 minutes• Shrinks on polymerization (2-3%)• Highly radiopaque• Easy to remove• Non-mutagenic and non-cytotoxic

• Biocompatible• Less irritating than epoxy resin or ZOE sealers• Resilon and epiphany improves the fracture

resistance of the roots ( through the formation of a monobloc ).

Hydron Greenberg –pressure syringe to extrude

cement into a canalKrakow and Berk popularized the ideaHydron:Goldman introduced Rapid setting hydrophilic plastic material

used as a root canal sealer without the use of a core.

Grossman defined it as a polymer of hydroxyl-ethyl methacrylate

Biocompatible material that conforms to the shape of the root canal because of its plasticity.

Canal must be dry , it sets in the root canal in 10 min

Requires a special syringe and a needle

Precaution: it is injected as an unset material and the polymers that hasten its set can cause tissue toxicity resulting in inflammation with macrophage activity.

Can cause paraesthesia

Silicon-based Root canal sealers

1. Lee Endofill2. Roekoseal3. Gutta flow

Lee Endofill

• Injectable silicon resin which is pale pink in colour.

• Sets to a rubbery solid • Can be used either as a sealer (with gutta-

percha) or to completely fill the canal (paste filler) using a precision syringe.

Base:• Hydroxyl terminated dimethyl polysiloxane• Undecylenic acid• Benzyl alcohol• Hydrophobic amorphous silica• Bismuth subnitrateCatalyst:• Tetraethyl orthosilicate• Polydimethyl siloxane

Properties:• Ease of preparation• Setting time can be adjusted from 10-60 min.• Has a low viscosity prior to setting• Allows good adaptation• Biocompatible• Easy to remove Disadvantages:• Cannot be used in the presence of hydrogen peroxide or sodium

hypochlorite• Canal must be absolutely dry• Shrinks on setting.

Roekoseal

• Is a polydimethyl siloxane-based root canal sealer

• Extremely low film thickness of only 5 micrometer

• Excellent flow properties flows into the smallest dentinal tubules

• Does not shrink excellent seal against bacteria

• Eugenol-free

Composition:• Polydimethyl siloxane• Silicon oil• Paraffin-based oil• Hexachloroplatinic acid (catalyst)• Zirconium dioxide (radiopaque material)

Gutta flow

• With gutta flow, an attempt has been made to incorporate the filling qualities of gutta-percha in the sealer.

• Gutta-perc ha is milled to a low grain size and is mixed into the components of the silicon sealer.

Composition:• Polydimethyl siloxane• Silicon oil• Zirconium oxide• Gutta-percha

NEW SEALERS

Bis –GMA( difficult to remove)Isopropyl cyanoacrylatePolyamide varnish Dentin bonding agents –good sealers because

of their ability to halt microleakage

Problems with dentin bonding agents:preparation of dentin to remove

smear layerradiopacity , metal salts need to be

added, which can affect polymerization

placement to ensure total, porosity free placement

removal in the event of failure

MIXING OF SEALER

Root canal cement is mixed on a sterile glass slab with a sterile spatula.

Slab is sterilized by an alcohol scrub and is dried and the spatula is passed through an open flame two or three times. Small increments of powder are added to the liquid while one spatulates it to a smooth creamy mix. Spatulation time depends on the number of drops of liquid used, a min per drop

Completed mix can be tested for proper consistency by raising the flat blade of the spatula up form the mixed mass. The cement should “string out” for at least an inch before breaking.

Another test is the suspended mix should cling to the inverted spatula blade for 10 to 15 sec before dropping from the spatula

PLACEMENT OF A SEALER

Reamer : is twirled counterclockwise, pumped and wiped against the walls

Absorbent paper points or gutta percha : pumping

Lentulo spiral: in a handpiece Disadv: locking in canal, “whipping up”

of cement in canal causing it to set prematurely

Ultrasonic file without use of a coolant

SEALER EFFICACYHovland and Dumsha “Although all root canal sealers leak to

some extent –there is probably a critical level of leakage that is unacceptable for healing and therefore result in endodontic failure. This leakage may occur at the interface of the dentine and sealer , at the interface of the solid core and sealer, through the sealer itself ,of by dissolution of the sealer”

All sealers leak. Some leak more than others mostly through dissolution.

The greater the sealer/periradicular tissue , the faster dissolution takes place

TISSUE TOLERANCE

Zinc oxide and Eugenol:All ZOE sealers dissolve in fluid

releasing eugenol which is irritating.Zinc oxide is also toxic due to the

effect of zinc ions.CRCS was the least cytotoxic

followed by AH26 ,Paraformaldehyde most toxicKetac Endo most biocompatible.

In vivo tissue tolerance examination:Erausquin and Muruzabal – found

that ZOE was highly irritating to the periradicular tissues and caused necrosis of bone and cementum.

Least irritating was Diaket and AH-26 .

Diaket becomes encapsulatedAH-26 was resorbed

• R. Gerosa et al conducted a study to assess the cytotoxicity of pure eugenol, by diluting it to various concentrations in alcohol. They concluded that pure eugenol is toxic for human gingival fibroblasts, and eugenol in an alcohol, solution at concentrations of <1.9 micrometer is non-cytotoxic.

• According to Brett I. Cohen PhD., Mark K. Pgnillo who conducted an invitro study to determine the cytotoxicity of two root canal sealers (AH 26 & AH Plus), both were considered cytotoxic.

• An invitro study to evaluate the relative cyto compatibiity of three endodontic materials: calcium hydroxide, a calcium oxide based compound and zinc oxide eugenol based compound was concluded by Martine Guigand, DDS, Pascal Pellen – Mussi, DDS. The results showed that, after 168 hrs all of the fibroblasts in contact with zinc oxide based compounds were dead. Fibroblasts in contact with calcium oxide based sealers, showed cell proliferation of 115% and those in contact with calcium hydroxide had a cell proliferation of 108%.

• A comparative study of tissue toxicity of 4 endodontic sealers – zinc oxide eugenol, Tubliseal, Sealapex and Endofloss by Meen Mittal et al and concluded that no inflammatory response was seen after 3 months, after injecting the sealers subcutaneously into rats.

CONCLUSION

REFERENCES

Pathways of the pulp , Cohen , (4th ,5th, 6th, 7th , 8th edition)

Endodontics , Ingle (4th ,5th edition)Endodontic therapy , Weine(5th and

6th edition)Endodontics in clinical practice ,

Harty(3rd &4th Edition)Journal references