ROOT CANAL SEALERS

In endodontic practice, the success of root canal therapy mainly

depend on achieving a compact fluid tight seal of the apical end of the root

canal, so as to prevent the ingress and accumulation of irritants causing

biological breakdown of attachment apparatus leading to failure. root canal

sealers along with solid core material plays a major role in achieving the

fluid tight seal.

The sealers are binding agents used to adapt the rigid gutta percha to

canal walls and to fill up the voids, accessory canals and irrigularities

within the canal. Several types of root canal sealers are used in endodontic

practice with each one having own merits and demerits.

Brief history:

1. In 1931 – The original zinc oxide eugenol cement was developed as a

root canal sealers by Rickert.

2. 1936, Grossman’s non-staining ZOE formula appeared as a sealer that

afforded more working time.

3. In 1952 Biocalex, a calcium oxide based sealer was introduced by

Bernord.

4. In 1955 – Scheufele introduced resin based Diaket as a sealer.

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5. In 1960 Wichterle and Lin introduced a plastic material Hydron.

6. In 1961, Tubliseal was introduced with a slight modification to Ricket’s

formula.

7. In 1965, Nyborg and Tullin gave a formula of Kloropercha.

8. In 1973, N2 a relatively recent formula by Sargnti was introduced for

root canal sealing purpose.

9. In 1976, Ailford recommended endodontic glass iononmer ketac-endo

as a root canal sealers.

Function of sealers

1) Binding agents – They form a band between filling and the dentinal

walls.

2) Antimicrobial Agents – It should have contain germicidal action.

3) As a filler – When used to fill the discrepancies between the bone and

the canal walls.

4) As a lubricant. It is for lubrication when used in conjunction with solid

care material like guttapercha.

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5) Radioopacity – is a property rather than a furcation which disclose the

presence of auxiliary canals, resparative areas, root fixtures and the

shape of the apical foramen.

Ideal Requirements

1. Should provide an excellent seal apically and laterally.

2. Should provide adequate adhesion when set.

3. Should be radioopaque.

4. Should be non-staining.

5. Should be diamentionally stable.

6. Should be easily mixed adequate working time and introduced into the

canal.

7. Should be easily removed if necessary.

8. Should be insoluble in tissue fluid.

9. Should have bacteriocidal or bacteriostatic action.

10. Should be non irritant to periapical tissue.

11. Should be absorbable when extruded into periapical regim.

12. Film thickness should be minim possible.

13. Should not be cytotoxic.

14. Should not be cariogenic.

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Classified

I. Based on their composition (Messing color Atlas)

a. Eugenol based.

i. Silver containing.

ii. Silver free.

b. Non eugenol based.

c. Medilated.

Silver containing are – e.g., Kerr Sealer, Procosol, (disadvantage

was staining of the teeth).

Silver free – We have E.g.:

- Procosol non staining.

- Grossman’s sealer.

- Tubliseal.

- Wach’s paste.

II. Non eugenol sealers

a. Diaket (resin based).

b. AH-26 (Resin based).

c. Khorperk and Eucaperch.

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d. Nogenol, Hydron endofil. GIC, Calcium phosphate, Cyanoacrylates and

polycarboxylates.

III. Medicated (These include group of sealers that have therapeutic

properties) E.g:

- N2 Endomethasone.

- SPAD.

- Idoform paste, Diaket, Riebler’s paste.

- CA(OH2) paste.

- Mynol cement.

According to Grossman

1. Zinc oxide cement

2. Calcium hydroxide cement.

3. Paraformal dehyde cement.

4. Pastes.

According to Cohen

Type I – Class I, Class II.

Type II – Class I, Class II, Class III.

Type III – Class I, Class II, Class III and Class IV.

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Type I

Class I – Metallic.

Class II – Polymeric

Type II

Class I - Powder and liquid non polymerizing.

Class II – Pastes and non polymerizing.

Class III – Polymer resin system

Type III

Class I - Powder and liquid non polymerizing.

Class II – Pastes and non polymerizing.

Class III – Metal amalgam.

Class IV – Polymers.

According to Clark

- Absorbable.

- Non-absorbable.

According to Ingle:

- Cements

- Paste.

- Pontics.

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According to Harty:

1.Zinc oxide eugenol based

- Tubliseal

- Wach’s paste.

- Grossman.

2. Resin based.

- AH-26.

- Diaket.

- Hydron.

3. G.P. based

- Chloropercha.

- Eucapercha.

4. Dentin Adhesive materials

- GIC.

- Cyanoacrylate.

- CaO2

- PO2

- Composite material.

- Polycarboxylate.

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5. Medicated cements

- Paraformaldehyde – calcium hydroxide.

- Calcibiofic (CRCS).

- Sealapex.

- Bicalex.

Nicholus (alphabetical order).

Eugenol based

I(a) Silver containing cements.

1. Kerr root canal sealer (Ricket’s formula).

Composition:

Zinc oxide 41.2%.

Precipitated silver 25-30%

Resins 16-30%

Tynol iodide 11-12%

Liquid

Eugenol 70-80%

Canada balsam 20-22%

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One drop of liquid is added to one packet of powder and mixed with

heavy spatula. Because of presence of precipitated sealing the granular

appearance remain when the spatulation is completed.

This sealer completely sets and is inert within 15-30 minutes, thus

reducing inflammatory response.

Kerr RCS are mainly recommended for warm G.P. technique where

lateral canals are present.

Advantage:

1. Excellent lubricating properties.

2. Working time is 30 minutes when mixed in 1: 1 ratio.

3. Germicidal action.

4. Biocompatible.

5. Because of granular structure greater bulk thus file voids, space and

auxiliary canals.

6. Prostogladin inhibition (zinc eugenol)

Disadvantage – presence of silver makes it extremely staining.

2) Procosal – again it is a silver containing cement.

Powder Liquid

Zinc oxide 45%

PPt silver 17%

Hydrogenerated resin 36%

MgO 2%

Eugenol 90%

Canada balsam 10%

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- This cement in granular in nature and fills and void and auxiliary

canals.

- Extremely staining cement.

Silver Free Eugenol Containing RCS

1) Procosol

Powder Liquid

Zinc oxide 40%

Stayblite resin 27%

Bismuth subcarbonate 15%

Barium sulphate 15%

Eugenol 80%

Oil of almond 20%

Grossmans cement

Most advocated cement because of:

- Good sealing ability.

- Stratifies most requirements.

Powder Liquid

Zinc oxide 40%

Stayblite resin 30%

Bismuth subcarbonate 15%

Barium sulphate 15%

Sodium bicarbonate amyhyrous 1

Eugenol 5 parts

Manipulation

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Mixed as sterile scale with spatulas, 2 to 3 drops of liquid is used

and powder is added in increments and mixed to a smooth creamy

consistency.

Cement hardens at approximately 2 hours at 37°C but in root canal

it begins to set with 10-30 minutes (because of moisture present in the

dentin).

The desirable properties of Grossman cement are:

1. Its slow setting time.

2. Plasticity.

3. This property is due to pressure of sodium bicarbonate amyhydrous.

Also it has good sealing potential, volumetric change upon setting is

very small.

Disadvantage

- Coarse resin particles may lodge on the canal wall preventing the root

canal filling from setting at cement level.

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2) Tubliseal

It is a two paste system: 1) Bare, 2) Catalyst.

Base paste Catalyst

1. Zinc oxide 57-59%

2. Olco resin 18-21%

3. Bismuth thioxide 75%

4. Thymol Iodide 3.75%-5%

5. Oil and waxes 10%

6. Barium sulphate

Eugenol polymerized resin

- Setting time is mixing pad is 20 minutes.

- In root canal it is 5 minutes.

Wach’s Sealer (1955)

Composition:

Powder Liquid

Zinc oxide 19gm

Tricalcium phosphate 2gms

Bismuth subcarbonate 3.5gms

Barium sulphate 0.3 gms

Heavy MgO 0.5gms

Eugenol 6 ml

Canada balsam 20 ml

- Medium or good working time.

- Minimum lubricating quality.

- Periapical irritation is minimal.

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- Possess germicidal action.

- Stages in position because of tactiness at the tip because of Canada

Balsam.

Disadvantage – Storage odour of the liquid.

To summarize:

1. Basically ZOE based one easy to manipulate.

2. Ample working time.

3. Adhesion is good because of limited dimensional changes.

4. Germicidal.

5. Radiopaque.

6. Minimal staining except for silver containing cements like Kerr and

Procosol.

The probable disadvantages are:

- Irritant to periapex and not easily absorbed from apical tissue.

Now for the setting reaction in brief:

Zinc oxide eugenol sets because of a combination of physical and

chemical reaction yielding to a hardened mass of zinc oxide embedded in a

matrix of long sheath like crystals of zinc eugenolate.

The presence of moisture, particle size, pH and additives are

important factors affecting the setting reaction.

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Tissue culture studies showed ZOE formulations to be cytotoxic.

The inflammation in the periapical region has shown to persist for

years until excess eugenol or ZOE cement absorbed or phagocytored by

macrographs.

II. Non eugenol sealers

1. Kloroperka Sealer : (P/L system)

Powder Liquid

Canada balsam 19%

Rosin 11.8%G.P. 19.6%

Zinc oxide 49%

Chloroform

The powder is mixed with liquid chloroform, after insertion the

chloroform evaporates having voids, it has been shown to be associated

with greater degree of leakage than any other sealers.

Because chloroform is a Kran Carcinogen.

Eucupercha was used

G.P. is dissolved in eucalyptol, which can be used either as sealer in

combination with G.P. cone or as cone filling materials. However it

exhibits, considerable shrinkage after setting.

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AH-26

It is a epoxy resin based sealer recommended by Shroeder in 1954.

Powder Liquid

Bismuth oxide 60%

Hexamethylene tetramine 25%

Silver powder 10%

Titanium oxide 5%

Bisphenol diglycidyl ether

The formation has been modified by eliminating silver powder to

prevent discolouration.

It has a very slow setting time.

36-48 hours at body temperature.

5-7 days at room temperature.

Advantages

- Is that good sealing ability.

- Possess antibacterial action.

- Low toxicity.

- Well tolerated by periapical tissue.

Disadvantages

- It contracts slightly while setting.

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- Parasthesia may access following the use AH-26, but recovery may

occur with 1-2 years.

- It inhibits leucocyte migration.

Diaket

It is a polyvinyl resin reinforced zinc oxide sealer chelates is formed

to zinc oxide and a small amount of pontic dissolved in liquid B-

diaketome.

Manipulation

- 2 drops of liquid is mixed with the scoop of powder and mixed to a

thick consistency.

- Changing the powder, liquid ration affects the hardness of the final set

and radioopacity.

Advantages:

- Also diaket is superior to other sealer in tensile strength and resistance

to permeability.

Disadvantages

- Setting time – 6-8 minutes on room temperature and even more rapid in

the root canal.

- Mild inflammatory reaction when diaket is overfilled. Diaket is known

(or its resistance to absorption).

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Diaket A

Chemically diaket A is similar to diaket and also contain the

disinfection “Hexachlorophene”. Diaket is one of the few medicated

cement which does not contain paraformaldehyde.

Hydron

It is a rapid setting hydrophillic, plastic material used as a root canal

sealer without the use of core or other words. Hydron is a polymer and

hydroxyethyl methacrylate (HEMA).

It is available as an injectable root canal filling material.

Working time is 6 to 8 minutes.

The syringe method makes it difficult to control the placement of

practice gel accurately. It is concluded to be biocompatible material that

conform to the shape of the canal also when in comes in contact with

moisture, the gel absorbs water and swells.

Endofill

Injectable silicon resin sealer which can be used in conjugation with

core material or as a sole filling material to be injected in to canal space

with pressure syringe.

It consists of silicon monomer and a silicon based catalyst plus

bismuth subnitrate as a radipacifier. The catalyst is tetra ethyl ortho silicate

polydimethyl.

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The mixed silicon has low working viscosity with good adaptation

to tooth structure and good protraction of accessory canals, it cures to pink

rubbery solid resembling G.P.

Silicone material in general exhibit low toxicity and are that to

tissue.

Glass Ionomer cement

Ketac-Endo

- The use of GIC for endodontic use was recommended in early 1970,s

by Putford.

- GIC is the reaction produce of an unleachable glass powder and

polyacrylic acid in organic solutions. On setting they form hard poly

salt gel which adhere to enamel and dentin. GIC is saturated and injured

into the root canal.

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Advantages

1. Good physical properties.

2. Good bonding to dentin.

3. Good flow properties.

4. Few voids.

5. Less cytotoxic

Disadvantages:

It cannot be removed in the even of re-treatment. However recent

studies shown that GIC can effectively removed by chloroform solvent

followed by 1 minute ultrasonic instrumentation.

Polycarboxylate cement:

Consists of modified zinc-oxide powder and an aqueous solution of

polyacrylic acid. The cement has chelating action bonding to both enamel

and dentin. Because of its adhesive property and antibacterial action of this

cement has be tested as root canal sealer. However apical seal is found to

be inferior to other materials. It exhibits an inflammatory response when

extruded into periapical tissue.

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Cyanoacrylic Cements:

These are composite type polymers that can be polymerized to hard

products by the use of basic inorganic material that also serves as filled.

They have been reported to be bio-compatible but not in much use.

Medicated cement:

The medicated sealers consists of paraformaldehyde, iodoform,

calcium hydroxide or other powerful antiseptics. They fail to provide a

compact root canal filling, but prolonged therapeutic effect.

Riebler’s paste : Paraformaldehyde based.

Powder / Liquid formulations:

Powder :

Zinc oxide.

Formaldehyde

Barium sulphate.

Phenol.

Liquid:

Formaldehyde

Sulphuric acid.

Ammonia

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Glycerine.

Mynol cement: Iodoform based

Powder:

Zinc oxide

Iodoform

Rosin

Bismuth Subnitrate

Liquid

Eugenol

Cresol

Thymol

These materials are used without core materials and are introduced

into root canal by lentulospiral or some type of infection device.

Paraformaldehyde containing paste exhibits severe inflammatory reaction

and tissue necrosis. Hence it is used as a sealer is restricted.

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Paraformaldehyde

N2 : Was introduced by Sargenti and Ritcher in 1961. Two type of N2

sealers were available initially i.e.:

N2, Normally for root filling and

N2, Apical as antiseptic medication.

Recently N universal a cement containing the feature of both N2

normal and N2 apical has been developed for endodontic use.

Composition:

Powder:

Zinc oxide

Lead tetraoxide

Paraformaldehyde

Bismuth subcarbonate

Titanium dioxide

Bismuth subnitrate

Phenyl mercuric borate

68.51 gms

12 gms

4.70 gms-Antiseptic

2.60gms – Opacifier

8.40gms- Adhesion

3.70gms – Opacifier

0.05 gms - Antiseptic

Liquid:

Eugenol

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Oleum Roae

Olum Lavandulae

Corticosteroids are now added separately as hydrocortisone powder.

Severe irritation is its major drawback of N2. Increased blood lead level

absorbed after N2 insertion.

Endometasone : Powder / Liquid

Powder:

Zinc oxide

Bismuth subnitrate

Dexamethasone

Thymol iodide

Paraformaldehyde

100gms

100gms

0.019gms

25 gms

2.20gms

Liquid

Eugenol

The powder is pink coloured and mixed with eugenol to thick

consistency. It exhibits severe irritation and masks the inflammatory

reaction. Therefore sometimes gives rise to pain after 6 to 8 hours of

insertion.

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Spad :

This material is advertised as a one visit non-irritant, radiopaque

filler and sealer. It is a resorbinol formaldehyde resin supplied as a powder

and 2 liquid.

Powder :

Zinc oxide 72.9gms

Barium sulphate

Titanium dioxide

Paraformaldehyde

Hydrocortizone acetate

Calcium hydroxide

Phenyl mercuric borate

Liquid L : (Clear liquid)

Formaldehyde 87.00 gms

Glygerin 13.00gms

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Liquid LD : (Red colour)

Glycerine 55gms

Resorcinol 25 gms

Hydrochloric acid 20 gms

Equal parts of the 2 liquids are mixed with powder. The essential

reaction to form the resin is between the resorcinol and the formaldehyde.

To take place this reaction and pH is essential which is provided by Hcl.

The role of zinc oxide is to control the pH and to prolong the setting time.

The setting time of SPAD is 24 hours, during which small quantities of

formaldehyde gas is released.

Indications:

1. Pulpotomies in both deciduous and permanent teeth.

2. For the treatment of acute endodontic infections.

3. Teeth with periapical infections.

When SPAD is used in the treatment of periapical infection, a small

amount is intentionally introduced beyond the apex with the belief that the

sterilizing effect helps healing.

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Calcium Hydroxide has been used in endodontics as a root canal

filling material, in intracanal medicament or as a sealant in conjugation

with solid core materials. Pure Ca(OH)2 can be used or can be mixed with

saline solution, methylecellulose or anesthetic solution. However pH of all

these mixtures has found to be between 12.5 to 14.5.

The use of Ca(OH)2 paste, as a root canal filling material is based

on the assumption that, there is formation of hard structure or tissue at the

apical foramen. Ca(OH)2 neutralizes the acids produced by bacteria and

thereby decreasing the osteoclastic activity. The activity of Ca(OH)2

stimulates the induction of alkaline phosphate thus forming the hard tissue.

Ca(OH)2 sealers may contain soley of Ca(OH)2 or it is combined

with zinc oxide. E.g., Sealapex, Apexit, CRCS. Procalex. Life Sealer 26.

Sealapex:

Is a product of Kerr manufacturing company has been described as

non eugenol Ca(OH)2 polymer resin root canal sealer.

Composition : It is a 2 paste formulation.

Base paste:

Zno with Ca(OH)2

Butyl Benzine.

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Sulfonamide

Zinc Stearite and sumicron silica.

Catalyst

Barium sulphate

Titanium dioxide

Isobutyl salysilate

Acrocil R 972

Two pastes are dispensed equally on mixing pad and mixed to a

smooth, uniform consistency. It never sets on dry atmosphere which makes

the presence of moisture essential for setting of sealapex. In 100% it takes

3 weeks to reach a final set. Sealapex expands while setting. It is

biocompatible and shows good osteogenic potential.

CRCS (Calcibiotic Root Canal Sealers):

It is the first sealer of the Ca(OH)2 group. It is basically a zinc oxide

eugenol eucolyptol sealer to which Ca(OH)2 has been added for its

osteogenic effect.

Composition : Powder / Liquid system).

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Powder :

Zinc oxide

Hydrogenated Rosin.

Barium sulphate

Calcium hydroxide

Bismuth subcarbonate

Liquid L :

Eugenol

Eucalyptol

CRCS is mixed like any other powder-liquid sealers. It sets both in

dry as well as wet conditions. It shows very negligible water sorption,

hence more stable, when compared to sealapex and other resin based

sealers.

Biocalex : Is another Ca(OH)2 based sealer consists of :

Powder:

Calcium hydroxide

Zinc oxide

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Liquid :

Glycol

Water

Powder and liquid when mixed to form a paste acts as both

intracanal medicament and as a sealer. After placement in the prepared

cavity, it expands to more than 6 times is original volume, penetrating into

all parts of root canal system.

Iodoform pastes :

Is a resorbable paste used alone or in combination with other core

materials. It consists of:

1. 60 parts of iodoform.

2. 40 parts of solution of Parachlorophenol

3. 49% Camphor (antiseptic solution).

4. 6% menthol (antiseptic solution).

Iodoform paste is intentionally placed beyond the apex to stimulate

the inflammatory reaction, the end result of which is repair. It also

accelerates the bone formation. The paste in periapical region is removed

by phagocytic action and slowly disappears with time.

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The disadvantage of iodoform paste is that it induces severe

inflammatory reaction and with time discoloration, the tooth if not

removed from the pulp chambers. The introduction of iodoform paste into

the root canal may lead to rise in the iodine level in blood, hence

contraindicated in patients who are sensitivity to iodine.

Newer sealers:

1. Endofloss.

2. Appetite Root canal sealer.

3. Root canal sealers containing Tetra-calcium – Dicalcium phosphate

and 1% chondrotin sulphate.

Endofloss:

Endofloss is a sealer consisting of powder liquid formulation.

Powder:

Zinc oxide.

Iodoform

Calcium hydroxide.

Barium sulphate.

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Liquid:

Eugenol

Parachlorophenol

It is a zinc oxide based medicated cement. Mixing is similar to that

of procosol (zinc oxide sealer). Setting time is approximately 30-45

minutes. Relatively biocompatible. It also a absorbable sealer.

It induces severe inflammatory reaction in 48 hours and gradually

reduced after 3 months. Cytotoxicity was observed along with coagulation

necrosis which is attributed in the presence of iodoform parachlorophenol.

Appetite root canal sealer

One of the recently introduced sealers.

Powder and Liquid Combination

Powder:

-tricalcium phosphate.

Hydroxyl apatite

Iodoform

Bismuth subcarbonate

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Liquid:

Polyacrylic acid.

Distilled water.

3 types – Type I, Type II and Type III

1) Type I : AR used for vital pulpectomy. Type II –30% iodoform used

in infected canals that has radiopacity, bactericide and bone invigoration effects.

Type III – in between cases which contains a 5% of iodoform. It can be also used in the

treatment of accident perforation, as a retrograde filling material.

Advantages Disadvantages

1. Biocompatible Sets quickly, hence multiple mix essential.

2. Osteogenic potential Low radiopacity

3. Low tissue toxicity Low wetting ability.

Newly Developed Calcium Phosphate type Sealers are:

a. Tetracalcium phospate (TeCP)

b. Dicalcium Phosphate Dihydrate (DCPD).

c. A modified McIIvain’s and Buffer solution (TDM).

d. TDM-S-Buffer solution + 2.5% Chondroitin sulphate.

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Composition : Powder and liquid systems

TDM-S TDM

Powder

Tetracalcium phosphate

Dibasic Calcium phosphate

Liquid

Citric acid

Dibasic sodium phosphate

Chondroitin sulphate.

Distilled water

Tetracalicum phosphate

Diabasic calcium phosphate

Citric acid

Diabasic sodium phosphate

Chondroitin sulphate

Distilled water

Studies have shown excellent biocompatibility.

No periapical inflammatory reaction seen.

Chondrotin and other ingredients said to promote wound healing.

Application of a Root canal sealer

RCS may be placed in the canals either by lentulospirals or by

Reamers and files. Lentulospiral is made up of fine wire spiraled into the

shape of a reverse spiral. It can be used by finger or attached to hand piece.

When spiral turned clockwise it carries cement apically. It should not be

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used in narrow canal for the reason that if binds result in breakage. It tend

to push cement outside the canal when used with handpiece and may set

too rapidly as a result of its whipping action.

Whatever may be the means of application it should be coated

uniformly along the canal walls (Coating the mater cone and accessory

cones with sealers is recommended as it reduces the voids and irregularities

within the canals.

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