NARAYANA DENTAL COLLEGE AND HOSPITALDEPARTMENT OF CONSERVATIVE DENTISTRY

AND ENDODONTICS

Seminar On

Root canal sealers

Presented by : -

Dr.T.Lenin Babu

CONTENTS

INTRODUCTION

REQUIREMENTS OF ROOT CANAL SEALER

SELECTION OF ROOT CANAL SEALER

CLASSIFICATION

Eugenol Based Root Canal Sealer

Kerr’s Sealer (Rickett’s Formula)

Grossman’s Sealer

Wach’s paste Sealer

Tubliseal

Non-eugenol Root Canal Sealer

Chloropercha

Nogenol

Calcium Hydroxide

Calcibiotic root canal sealer

Seal Apex

Life

Apexit

Vitapex

Powders and Resins

Diaket

AH-26

AH-plus

Endofill

Glass Ionomer (Ketac-Endo)

Formaldehyde containing root canal sealer

Experimental root canal sealer

EFFICACY OF ROOT CANAL SEALER

TISSUE TOLERANCE OF ROOT CANAL SEALER

STUDIES RELATED TO ROOT CANAL SEALER

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INTRODUCTION

The sealer plays an important role in the obturation of root

canal. The Sealer fills all the space the gutta percha is unable to fill

because of gutta-percha’s physical limitations. The sealer acts as a

binding agent, to the dentin and to the core material, which usually

is gutta percha. The sealers are usually a mixture that hardens by

chemical reaction, such reaction normally includes the release of

toxic material, making the sealer less biocompatible.

Several sealer and cements, such as AH-26, AH-Plus, Ketac-

Endo and Diaket may be used as the sole filling material because

they have sufficient volume stability to maintain a seal. Under such

preventing excess is often difficult because the sealer is applied

with a lentulo spiral.

There are a variety of sealers from among which to choose

and the clinician must be careful to evaluate all characteristics of a

sealer before selecting.

Sealer helps to fill in irregularities and minor discrepancies

between the filling and canal walls, accessory canals and multiple

foramina. Sealer discloses the presence of ancillary canals,

resorptive areas, root fractures, shape of the apical foramen and

other structures due to its radio-opacity. A sealer is a good lubricant

and helps in the seating of primary cone into the canal. It is a good

germicidal or antibacterial.

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REQUIREMENTS FOR AN IDEAL ROOT CANAL SEALER:

It should be tacky when mixed to provide good adhesion

between it and the canal wall when set.

It should make a hermetic seal.

Sealers should have ample setting time, giving the clinician

sufficient time to make necessary adjustments to the filling

material.

The particles of powder should be very fine so they can mix

easily with the liquid.

It should not shrink upon setting

All the Sealers shrink slightly upon setting and gutta percha

also shrinks when returning from a warmed of plasticized

state.

It was found that zinc oxide eugenol sealers begin shrinking

within hours after mixing, but that AH-26 and Endo-fill first

expanded and showed no shrinkage for 30 days. The least

dimensional change at any time was observed for Endo-fill.

Significant dimensional change and continued volume loss can

occur in some endodontic sealers.

Sealers should not stain tooth structure.

The admonition that sealers and filling materials “should not

stain tooth structure”, Grossman’s requirement is evidently

being violated by a number of sealers.

Vander Burgt from Holland and her associates reported,

“Grossman’s cement, zinc-oxide eugenol, Endomethasone,

and N2 induced a moderate orange red stain to the crowns of

upper premolar teeth.

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She further found that “Diaket and Tubliseal caused a mild

pink discoloration whereas AH-26 gave a distinct color shift

towards gray.

On the other hand ‘Rieblers paste caused a severe dark red

stain. Diaket caused the least discoloration.

As far as the staining ability of other materials is concerned,

Vander Burgt found that Cavit produced “a light to moderate

yellowish /green stain that gutta percha caused a milk pinkish

tooth discoloration,” that AH-26 Silver free and Duo Percha

induced a distinct color shift towards gray” and that crowns

filled with IRM and Dycal became somewhat darker.

No discolorations were recorded for teeth filled with Durelon,

Fuji glass ionomer, Fletchers cement, or zinc phosphate

cement.

Sealers that contain silver as radio opacifier, such as Kerr’s

Root Canal sealers (Rickett’s Formula) or the original AH-26

are notorious as tooth strainers.

It should be bacteriostatic, or at least not encourage

bacterial growth.

Grossman tested 11 root canal cements and concluded that

they all exerted antimicrobial activity to a varying degree,”

those containing para-formaldehyde to a greater degree

initially. With time however, this latter activity diminished so

that after 7 to 10 days the formaldehyde cements were no

more bactericidal than other cements.

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More recently a British group studying the antibacterial

activity of four restorative materials reached much the same

conclusion regarding zinc oxide eugenol and glass ionomer

cement.

Another study founded that 10 sealers inhibited growth of

streptococcus sanguis and streptococcus mutans.

A Temple university study found that Grossman’s sealer had

the greatest overall antibacterial activity, but that AH-26 was

the most active against bacteroides endodontalis, an

anaerobe.

Sealers should be insoluble in tissue fluids.

Smith and McComb found a wide variance in sealer solubility

after 7 days in distilled water, ranging from 4% for Kerr’s pulp

canal sealer to much less than 1% for Diaket.

Peters found after two years that virtually all the sealer was

dissolved out of test teeth filled by lateral or vertical

compaction. Therefore most sealers are soluble to some

extent.

It should set slowly.

It should be tissue tolerant that is non-irritating to

periradicular tissue.

Para formaldehyde containing sealers appear to be the most

toxic and irritation to tissue. A case in point is reported from

Israel necrosis of the soft tissue and sequestration of crestal

alveolar bone from the leakage of para formaldehyde paste

from a gingival level perforation.

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It should be soluble in a common solvent if it is necessary to

remove the root canal filling.

It should not provoke an immune response in periradicular

tissue.

It should be neither mutagenic nor carcinogenic.

SELECTION OF SEALER

For use with gutta-percha, appropriate sealers should be

selected to aid in the filling of the canal. The operator should

determine the amount of lubrication needed, the length of working

time estimated, and the filling material to be used before deciding

which sealer or sealers would best perform the necessary function.

In lateral condensation methods use of sealer should be

minimal, since the compressible filling material will be able to fill

most irregularities. All the sealers have resorbable properties when

expressed into periapical tissue, although rarely has resorption of

the sealer within the canal been noted. Still, it is preferable to seal a

canal with the packed solid-core material, which is largely un-

resorbable, as compared to the sealer.

A good sealer should be biologically compatible and well

tolerated by the periapical tissues. All sealers are highly toxic when

freshly prepared; however their toxicity is greatly reduced after

setting takes place. A few days after cementation practically all root

canal sealers produce varying degrees of periapical inflammation

(usually temporary); this usually does not appear to prevent tissue

healing and repair.

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Although most cement sealers were highly irritating to

periapical tissues, the most severe alveolar and bone destruction

was caused by poor debridement and poor filling of the root canal

system. Minimal tissue reaction was found when the canal was not

over-filled. Over instrumentation and overfilling caused immediate

periapical inflammation, which tended to persist and to cause

epithelial proliferation and cyst formation. In teeth filled short of the

foramen, the reaction was temporary and complete repair

eventually took place.

ROOT CANAL SEALER CEMENTS

In most clinical situation, core materials are used with root

canal sealer cement. The bond between the sealer and the core

material is non-adhesive. The core and sealer root canal filling

techniques involve 2 inter phases – one between the core and the

sealer and the other between the sealer and dentin.

Root canal sealer cements are divided into:

1) Eugenol based cement

2) Non-Eugenol based cement

EUGENOL BASED SEALER CEMENTS

Many root canal cements are based on zinc oxide eugenol,

which is known to provide a good seal.

Many endodontic sealers are simply zinc oxide eugenol

cements that have been modified for endodontic use.

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The mixing vehicle for these materials is mostly eugenol. The

powder contains zinc oxide that is finely sifted to enhance the flow

of the cement.

Setting time is adjusted to allow for adequate working time.

One millimeter of zinc-oxide eugenol cement has a radio-

opacity corresponding to 4-5 mm of aluminum, which is slightly

lower than gutta-percha. These cements easily lend themselves to

the addition of chemicals and para-formaldehyde is often added for

antimicrobial and mummifying effects, germicides for antiseptic

action, rosin or Canada balsam for greater dentin adhesion, and

corticosteroids for suppression of inflammatory reaction.

Zinc oxide eugenol sets because of the combination of

chemical and physical reaction, yielding a hardened mass of zinc

oxide embedded in a matrix of a long sheath like crystals of zinc

eugenolate [C10 H11 O2]2 Zn. Excess eugenol is invariably present and

is absorbed by both zinc oxide and eugenolate. The presence of

water, particle size of the zinc oxide, the pH and the additives are all

important factors in the setting reaction.

Hardening of the mixture is due to zinc eugenolate formation;

unreacted eugenol remains trapped and tends to week and the

mass.

All zinc oxide eugenol cements have an extended time but set

faster in the tooth than the glass slab, due to increased body

temperature and humidity. If the eugenol used in Grossman’s

cement becomes oxidized and brown, the cement sets too rapidly

for ease of handling. If two much sodium borate has been added,

the setting time is overextended.

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The original zinc oxide-eugenol cement, developed by

Rickert’s, was the standard for the profession for years. It admirably

met the requirement set by Grossman for severe staining. The

silver, added for radiopacity, causes discoloration of the teeth, thus

creating an undesirable public image for endodontics. Removing all

cement from the crowns of teeth would prevent these unfortunate

incidents.

In 1958, Grossman recommended non-staining zinc oxide

eugenol cement as a substitute for Rickert’s formula. It has become

the standard by which other cements are measured because it

reasonably meets most of Grossman’s requirements for cement.

The most common zinc oxide eugenol cements are Rickert’s

sealer, Grossman’s sealer, Wach’s paste, Tubliseal.

KERR’S SEALER (Rickert’s formula)

Rickert’s formula was developed in 1931 as an alternative to

the chloropercha, eupercha sealers of the period. Gutta-percha

based sealers mentioned above lacked dimensional stability after

setting. Rickert’s formula was developed to eliminate this problem.

Powder contains

Zinc Oxide 41.2 parts

Precipitated silver 30.0 parts

White resin 16.0 parts

Thymol iodide 12.8 parts

Liquid

Oil of clove 78 parts

Canada balsam 22 parts

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Setting time

Half an hour

Advantages:

The powder in Kerr’s sealer acts as a good germicidal.

It has excellent lubricating and adhesive qualities.

It has the ability to increases the body of Kerr’s sealer.

Disadvantages:

Staining due to presence of silver. Any Surplus of the

cement in the crown of an anterior tooth should be removed

immediately after root fillings.

Prolonged spatulation during mixing is needed to break up

particles and reduce viscosity due to large particle size.

INDICATIONS

Warm vertical condensation of gutta percha when lateral

canals are anticipated. Since the silver present in the

powder is radio opaque, the lateral canal with the sealer is

the silver rather than the mass of sealer mix or any

softened gutta percha.

Weine has observed that lateral canals demonstrated with

Kerr’s sealer remained observable radiographically for

longer than do such canals with Wach’s paste.

Obturation with silver points

10

CONTRAINDICATIONS

Sealer not advised in anterior. If used, the pulp chamber

should be washed out with xylol after condensation of gutta percha

to ensure removal of sealer.

MANIPULATION

Supplied as pellets or bulk (powder) and the liquid in a

dropper bottle. One drop of liquid to one pellet of powder (1:1 ratio)

is taken and mixed with a heavy spatulation until relative

homogeneity is obtained. Because of the precipitated silver, some

granular appearance remains even when the spatula is completed.

GROSSMAN’S SEALER

Due to the relatively rapid setting time of Rickert’s sealer,

Grossman’s formula appeared an 1936, with the purpose of

developing a sealer that afforded more working time.

PROCOSOL RADIOPAQUE SILVER CEMENT

Composition

Powder contains

Zinc oxide USP - 45.0%

Silver (precipitated) - 17.0%

Hydrogenated resin - 36.0%

Magnesium oxide - 2.0%

Liquid contains

Eugenol - 90.0%

Canada Balsam - 10.0%

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However, the use of precipitated silver for radiopacity was

criticized. So a revised version of Grossman’s formula was marketed

for many years as

PROCOSOL NON STAINING ROOT CANAL CEMENT (Grossman

1958)

Powder contains

Zinc oxide (reagent) - 40.0%

Stabelite resin - 27.0%

Bismuth sub-carbonate - 15.0%

Barium sulfate - 15.0%

Liquid contains

Eugenol - 80.0%

Sweet oil of Almond - 20.0%

Grossman’s formula was again revised by the addition of

sodium borate to the powder component and by the elimination of

all in Ingredient except eugenol from the liquid component.

GROSSMAN’S SEALER (Grossman, 1974)

Power contains

Zinc Oxide - 42%

Stabelite resin - 27%

Bismuth sub carbonate - 15%

Barium sulfate - 15%

Sodium borate (anhydrous) - 1%

Liquid contains

Engenol - 100%

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Setting time:

2hrs at 37 C

In the root canal, setting time 10-30 minutes due to the

presence of moisture in the dents.

Factors influencing the setting time:

1) Quality of zinc oxide

2) pH of resin

3) Technique of mixing to its proper consistency.

4) Amount of humidity

5) Temperature and dryness of mixing slab and spatula

MANIPULATION

Sterile glass slab and spatula are taken. Not more than 3

drops of liquid should be used at a time, because excessive time

and effort would be required to spatulate a large amount. Small

increments of powder is added to liquid and mixed to a creamy

consistency.

Spatulation time – 1 minute/drop

The cement will not harden for 6-8 hrs if left on the glass slab.

The mixed batch of cement can therefore be used for several

hours. If it thickens, spatulation will break up any crystals formed

and will restore the mix to proper consistency. In the canal, because

of moisture in the dentinal tubules, it begins to set in half an hour.

TEST FOR PROPER CONSISTENCY

DROP TEST

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The mass of cement is gathered onto the spatula, held

edgewise, the cement should not drop off the spatula’s edge for 10-

12 sec. A root canal instrument can be used for this test. After a

no:25 file is rotated in the gathered mass of cement, it is withdrawn

and held in a vertical position. A correctly mixed cement should

remain with very little movement in the blade of the instrument (5-

10 sec). If a tear drop forms, the mix is too thin and more powder

should be added.

SPRING TEST

After touching the mass of cement with its flat surface, the

spatula is raised slowly from the glass slab. The cement should

string out atleast one inch without breaking.

ADVANTAGES

The use of Grossman’s sealer reduced leakage nearly 50%

when they compared lateral condensation and compaction methods

with or without the use of sealer. Plasticity and slow setting time

due to the presence of sodium anhydrate. Grossman’s sealer has a

good sealing potential. There is small volumetric change upon

setting. The sealer has the ability to be absorbed in case of apical

extrusion of the sealer during canal obturation.

Grossman’s sealer is soluble in chloroform, carbon

tetrachloride, xylol and ether. The sealer is easily removed from the

glass slab and spatula with alcohol or solvent.

It present a minimal level of irritation and high level of

antimicrobial activity.

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DISADVANTAGES

Zinc eugenolate can be decomposed by water through a

continuous loss of eugenol making zinc oxide eugenol a weak,

unstable material.

Toxicity studies have shown that a small amount when

extruded may first cause an inflammatory reaction, nevertheless it

is well tolerated by the periapical tissues. When a periapical lesion is

present, a transient toxic effect of the medicament is permissible

because healing continuous longer than toxicity. Often the excess

is removed from the periapical tissues by phagocytosis.

WACH’S PASTE

Wach’s paste, a variant of zinc oxide eugenol formula was

originally formulated in 1925, but did not receive widespread

adoption until its publication and reintroduction in 1955. It first

became popular in Chicago Beachwood creosate is added as a

medical component. It is highly desirable sealer for use with gutta-

percha.

COMPOSITION

It is dispensable as powder and liquid.

The powder contains

Zinc Oxide - 61.0 – 61.4%

Calcium phosphate tribasic - 12.0 – 12.2%

Bismuth sub-nitrate - 21.0 – 21.4%

Bismuth sub-iodide - 1.9 – 2%

Magnesium oxide - 3.1 – 4.0%

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Liquid contains:

Canada balsam - 74 .0 – 76.9%

Oil of cloves - 22.0 – 23.1%

Eucalyptol - 2.0%

Beechwood creosate - 2.0%

INDICATIONS

Wach’s paste is indicated in all lateral condensation methods

especially when chance of overfilling is present

CONTRAINDICATIONS

Wach’s paste is contraindicated when heavy lubrication is

needed as with short master cone.

ADVANTAGES

Wach’s paste has a smooth consistency without a heavy body,

it is useful in small curved canals of minimal calibre as this light

body does not deflect the small gutta percha used to fill these

canals.

The sealer is very sticky due to the presence of Canada

balsam. Hence the paste will remain on the reamer during

placement until it is spun off in the apical portion of the preparation

and does not completely rub off on the canal walls during insertion.

Hence sealer loaded on the tip stays in position.

It is a good germicidal Relatively low tissue irritant .

The sealer is biocompatible to the periapical tissue. It has a

good setting time.

DISADVANTAGES

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Wach’s paste has medium working time and has less

lubricating quality.

MANIPULATION

The sealer is supplied as powder and liquid separately. One

drop of liquid is used with an appropriate amount of powder. No

measuring device is included with the powder, so sample batches

should be mixed to enable the mixer to tell what amount gives

desirable results.

Mixed to a creamy smooth consistency and should string out

atleast one inch when spatula is raised from the glass slab.

Larger canals generally require a slightly thicker mix and also

if there is any chance of overfilling.

TUBLISEAL

This sealer was introduced by Kerr manufacturing company in

1961, as an alternative to Rickert’s formula. Tubliseal is a two paste

system as opposed to the powder liquid system of other zinc oxide

types.

Base paste contains

Zinc Oxide - 57.4 - 59.0%

Oleo resins - 18.5 - 21.25%

Bismuth Inoxide - 7.5%

Thymol Iodine - 3.5% - 5%

Oils and Waxes - 10.0 - 10.1%

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The catalyst contains

Eugenol

Polymerised resin

Annidalin

Some base paste also contains barium sulfate as radio

opacifier, mineral oil cornstarch and lecithin.

The catalyst paste may contain polypale resin, eugenol and

thymol iodide.

MANIPULATION

Tubliseal sealer is contained in two collapsible tubes

containing a base and accelerator which when mixed together to

about half an inch (which is sufficient in most cases) forms a creamy

mix.

ADVANTAGES

The sealer does not stain the tooth structures. It is extremely

lubricating has a high rate of flow giving a thinner film.

It allows maximal condensation in packing.

Since the sealer is white in colour it provides a good contrast

to the flapped tissue during surgical procedures.

DISADVANTAGES

Since the Tubliseal sealer has a very low viscosity it makes

extrusion through the apical foramen more likely and recommends a

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short spatulation time and leaving the cement for a short period

before use.

The Tubliseal sealer is very irritating to the periapical tissue,

causing considerable periapical sensitivity when used in teeth where

the pulp was vital and the periapical tissue normal before

treatment. But this can also be turned into an advantage, when it is

used in teeth where a large radiolucency is present, since the sealer

may act as a stimulant to the periapical area.

The working time of the sealer is less than 30 minutes and

even shorter in the presence of moisture.

In multi-rooted teeth for which a longer working time is

necessary plans should be made to use more than one mix.

Additionally great care should be exercised to ensure that all

canals are as dry as possible prior to sealer insertion and extra

wiping with paper points provide additional insurance against

moisture.

INDICATIONS

Tubliseal sealer is used in instance when shorter setting time

is required (eg) where a root filling is to be followed immediately by

apicectomy.

This sealer is used in cases where master cone becomes

difficult to reach last millimeter of the preparation, due to its

lubricating property.

CONTRAINDICATIONS

Tubliseal sealer is contraindicated if overfill is probable with

normal periapical issue.

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This sealer should not be used in multi-rooted tooth where

longer working time is necessary.

NON-EUGENOL SEALER CEMENTS

The Two sealer cements that do not contain eugenol are

1) Chlorepercha

2) Nogenol

CHLOROPERCHA

This is a type of sealer that has been in use for many years. It

was introduced in 1939 in Norway. Chloropercha (Myco) is a direct

descendent, relatively unaltered, of material in use for nearly a

century.

Chlorepercha is obtained by mixing gutta percha with

chloroform. This will allow a gutta percha root filling to fit better in

the canal. It is important to recognize however, that chlorepercha

has no adhesive property.

Various forms of chloropercha have a radio-density (1 mm

thick) corresponding to only 1.2 to 2.7 mm of aluminum, which is

much less than 1mm of gutta percha at 6.4mm of aluminium. These

sealers appear vague on radiograph.

One variant of chloropercha technique is to use a mixture of

5% to 8% of resins in chloroform. A rosin chloroform wash of the

root canal leaves a very adhesive residue. This residue in

combination with dipping of the gutta-percha cone in resin

chloroform provides the sealer in this technique. This is a difficult

technique because there is no sealer to fill areas where there are

voids between the gutta percha cones.

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Chloroform technique for obturation requires that the operator

has good basic skills with various obturation technique, because the

technique is very sensitive to proper manipulation.

When the chloroform technique is correctly used the

shrinkage is not greater than when the gutta percha is plasticized

by heat.

The use of chloroform has been sharply curtailed in recent

years because of its projected toxicity. Thus when used for softening

of gutta percha during revision of old root fillings, the chloroform

should be dispensed through a syringe and hypodermic needle. For

other uses the exposure time, amount used and chloroform surface

exposed should all be kept to a minimum.

The general problem with most chloropercha products is their

shrinkage during the evaporation or disappearance of the

chloroform. Some brands such as chloropercha N- contain filler

particles (eg zinc oxide) to reduce the shrinkage. Zinc oxide also

increases radio opacity.

COMPOSITION

KLOROPERCHA N – (NYGARD – OSTBY 1939)

Powder contains

Canada Balsam - 19.6 %

Rosin - 11.8 %

Gutta percha - 19.6 %

Zinc oxide - 49.0 %

Liquid contains

Chloroform - 100 %

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DISADVANTAGES OF CHLOROPERCHA

Chloro percha is carcinogenic

Chloro percha products undergo shrinkage of during the

evaporation of chloroform.

It acts as an irritant to the periapical tissues.

Chloro percha has been shown to be associated with a

greater degree of leakage than other materials.

INDICATIONS OF CHLOROPERCHA

Chloro percha produces excellent result in the filling of

unusual curvatures or where the apical part of root canal is

inaccessible and also in cases of perforation and ledge formation.

It is used in case of canals, which divide in the apical part of

the root into two major branches, these can be forced beyond the

level of division into the unfilled canal if filling of one severely

restricts the access to the other.

CHLOROPERCHA (MYCO)

Gutta percha - 9 %

Chloroform - 91.0 %

NOGENOL

This was developed to overcome the irritating quality of

eugenol. The product is an outgrowth of a non-eugenol periodontal

pack.

COMPOSITION

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Base

Zinc oxide with barium sulfate as a raiopacifer along with

vegetable oil.

Catalyst

The setting of the sealer is accelerated by hydrogenated rosin,

methyl abeitate, lauric acid, chlorothymol and salicylic acid

ADVANTAGES

Nogenol is a less irritating sealer

The sealer expands on setting and may improve its sealing

efficacy with time.

CALCIUM HYDROXIDE SEALERS

Calcium hydroxide has can advantage over zinc oxide eugenol

because of its ability to preserve the vitality of pulp stump. Several

calcium hydroxide based sealers have been brought to the market.

Examples of such sealers are sealapex (Kerr) Calciobiotic Root canal

Sealer (CRCS) and Apexit (Vivadent).

These sealers are promoted as having therapeutic effect

because of the calcium hydroxide content. However no such

convincing results from scientific trials have been shown. To be

therapeutically effective calcium hydroxide must be dissociated into

Ca++ and OH. Therefore to be effective, an endodontic sealer

based on calcium hydroxide must dissolve and the solid

consequently lose content, Thus one major concern is that the

calcium hydroxide content may dissolve, leaving obturation voids.

This would ruin the function of the sealer, because it would

disintegrate in the tissue. These sealers also have poor cohesive

strength. There is no objective Proof that the calcium hydroxide

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sealer provides only advantage for root canal obturations or has any

of the desirable biologic effects of calcium hydroxide paste.

In a study of diffusion of hydroxyl ions into surrounding dentin

after root filling with seal apex and Apexit no traces were found in

teeth with Apexit Some hydroxyl ions could be detected in the

dentin close to the root filling with sealapex.

In a similar study of calcium and hydroxyl ions release from

Sealapex and CRCS, negligible release was noted from CRCS.

Sealapex released more ions but disintegrated in the process.

Studies in vivo of sealapex and CRCS have demonstrated that

Sealapex and CRCS easily disintegrate in the tissue. They both

cause chronic inflammations considering the alternatives, calcium

containing sealers are not a practical choice of materials.

CALCIBIOTIC ROOT CANAL SEALERS (CRCS)

It is essentially a zinc oxide eugenol/eucalyptol sealer to which

calcium hydroxide has been added for its so-called osteogenic

effect.

It represents the first of the calcium hydroxide based sealers.

Contains 14% by weight of calcium hydroxide. It takes 3 days to set

fully either in dry or humid environment This means that it is quiet

stable and improves its sealant qualities but brings into question its

ability to actually stimulate cementum or bone formation. It calcium

hydroxide is not released from the cement, it cannot exert an

osteogenic effect and thus its intended role is negated.

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CRCS is supplied as powder and liquid component

Powder contains

Calcium Hydroxide

Zinc Oxide

Bismuth dioxide

Balsom Sulfate

Liquid contains

Eugenol

Eucalyptol

SEAL APEX

It is also a calcium hydroxide containing sealer delivered as

paste to paste in collapsible tubes

COMPOSITION

Base Contains

Zinc Oxide 6.5 %

Calcium hydroxide 25.0 %

Butyl benzene

Sulfonamide

Zinc stearate

Catalyst contains

Barium sulfate 18.6 %

Titanium dioxide 51 %

Proprietary resin

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Isobutyl salicylate

Aerocil R 972.

In 100% humidity, seal apex takes 3 weeks to set. In a dry

atmosphere it never sets. It expands on setting. A negligible amount

of dissolution occurred when extruded from the periapex. The

dissolution was probably due to water sorption Thus eventually

breaking the apical seal. The fluid sorption characteristics may be

due to its porosity that allows marked ingress of water. It is

biologically active sealer intended to promote periapical healing.

Holland reported the ability of sealapex, to induce apical

closure by cementum in histological studies.

LIFE

It is a calcium hydroxide liner and pulp capping material

similar in formulation to Sealapex, has also been suggested as a

sealer.

APEXIT

From Liechtenstein comes an experimental calcium hydroxide

sealer called Apexit. Australians found that it sealed better than

Imbiseal.

COMPOSITION

Base

Calcium hydroxide 31.9 %

Zinc oxide 5.5 %

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Calcium Oxide 5.6 %

Silicon dioxide 8.1 %

Zinc stearate 2.3 %

Hydrogenised colophony 31.5 %

Tricalcium phosphate 4.1 %

Poly dimethyl siloxane 2.5 %

ACTIVATOR

Trimethyl hexanedioldisalicylate 25.0 %

Bismuth carbonate basic 18.2 %

Bismuth oxide 18.2 %

Silicon dioxide 15.0 %

1,3 Butanediol di Salicylates 11.4 %

Hydrogenised colophony 5.4 %

Tricalcium phosphate 5.0 %

Zinc stearate 1.4 %

VITAPEX

This sealer is introduced by Japanese. Its components appear

to be iodoform and silicone oil. One week following deposits in rats,

Vitapex containing calcium ions labeled calcium hydroxide, was

found throughout the skeletal system. This attests to the dissolution

and uptake of this material. No evidence is given about the sealing

or osteogenic capabilities of Vitapex.

POWDERS AND RESINS

Other sealers that enjoy favour worldwide are based more on

resin chemistry than essential oil catalysts. Now sealers are mostly

polymers. The more common brands are Diaket, Endofill, AH-26, AH-

Plus.

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DIAKET

Diaket, an early one, first reported in 1951, is a resin

reinforced chelate formed between zinc oxide and a small amount

of plastic dissolved in the liquid, di-ketone. A very tacky material,

it contracts slightly while setting, which is subsequently negated by

uptake of water. Its setting efficacy is good.

Powder:

Zinc oxide 98.0%

Bismuth phosphate 2.0%

Liquid:

2,2-Dihydroxy 5.5’

dichlorodiphenylmethane

Proplonylacetaphenone

Triethanolamine

Caproic acid

Copolymer of vinyl acetate,

Vinyl chloride, and vinyl

Isobutyl ether

AH-26 ROOT CANAL SEALER

AH-26 is an epoxy resin that initially was developed to serve

as a single filler material. Because of its good handling

characteristics it has been exclusively used as a sealer. It is glue,

and its base is bisphenol A-epoxy. The catalyst is hexamethylene

tetra mine. It also contains 60% bismuth oxide for radiographic

contrast. One millimeter of AH-26 has a radiopacity corresponding

to 6.66 mm of aluminum, thus it is very similar to gutta percha.

It has a good flow, seals well to dentin walls and allows for

sufficient working time. As AH-26 sets, traces of formaldehyde are

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temporarily released which initially makes it antibacterial AH-26 is

temporarily toxic while the setting takes place, but the toxicity is

one of the lowest of all endodontic sealers after 24 hrs. This is due

to the release of very small amount of formaldehyde, as a result of

chemical setting process.

This amount of brief release formaldehyde however is

thousands of times lower than the long-term release from

conventional formaldehyde containing sealers, such as N.

AH-26 is not sensitive to moisture, and will even set under

water. It will not set, however if hydrogen peroxide is present. It sets

slowly in 24 to 36 hours. The Swiss manufacturer of AH-26

recommend that mixed AH-26, be warmed on a glass slab over an

alcohol flame, which renders it less viscous. AH-26 is also sold world

wide as thermaseal.

COMPOSITION

Powder

Silver Powder 10%

Bismuth oxide 60%

Hexamethylenetatramine 25%

Titanium oxide 5%

Liquid

Bisphenoldiglycidyl ether 100%

AH-PLUS ROOT CANAL SEALER

A new formulation of AH-26 is now available called AH plus.

This is a paste and paste mixing system that assures a better

29

mixture. It has an increasing radiopacity, shorter setting time, lower

stability and a better flow compared with AH-26.

The material sets quickly in the root canal at body

temperature but remains soft longer at room temperature. It is

highly toxic in vitro and causes extensive tissue necrosis. This

irritation is long lasting

COMPOSITION

Epoxy paste (A)

Epoxy resin

Calcium tungstate

Zirconium oxide

Aerosil

Iron oxide

Amine paste (B)

Adamantane amine

N,N – Di benzyl –5- oxanonanediamine

Calcium tungstate

Zirconium oxide

Aerosil

Silicon oil

Two additional root canal sealers have been marketed: one a

silicone rubber like material called Lee Endofill and the other glass-

ionomer cement called ketac-Endo.

ENDOFILL

Endofill, when set has a rubbery consistency. Initially the

manufacturer recommended that it be injected into the canal as the

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sole sealer. Overzealous dentists, not following the instructions,

ejected the material out through the apex and court cases ensued.

This is remarkable in that Endofill is virtually nontoxic the least

irritating sealer on the market. When used properly as a sealer with

gutta percha it is quite similar to other sealers.

COMPOSITION

The base of Endo-Fill is heavily loaded with bismuth sub

nitrate as radio opacifier. Hence it is densely radiopaque. The active

ingredients are hydroxyl terminated dimethyl poly-siloxane,

undecylenic acid, benzyl alcohol and hydrophobic amorphous silica

(10 to 30 milli microns particle size).

The catalysts are ethyl ortho silicate, poly dimethyl siloxane

and catalyst intermediate.

ADVANTAGES

It is easy to prepare,

It has a adjustable working time, low viscosity and rubbery

in consistency. It is easy to remove as Gutta Percha.

DISADVANTAGES

The endofill cannot be used in the presence of hydrogen

peroxide and the canal must be absolutely dry.

It also shrinks upon setting, but has an affinity for flowing into

tubuli.

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GLASS IONOMER CEMENT (Ketac-Endo)

Recently glass ionomer cements have been introduced as

endodontic sealers (Ketac-Endo). Glass ionomer cements are known

to cause less tissue irritation. It has a low toxicity in vitro. Little

biological data are available relative to its use as an endodontic

sealer, so safety and efficacy of glass ionomer cements have not

been established. There are questions about the quality of the seal

with Ketac Endo because of observed dentin and sealer adhesive

failures.

Saito suggested using Fiji Type I luting cement to fill the entire

canal.

Pittford in England recommended endodontic glassionomer as

early as 1976. However he found that setting time was too rapid.

Stewart was combining Ketac-Bond and Ketac-Fill before these glass

ionomers were specifically formulated for endodontics.

At Temple University, eight different formulation of Ketac

cement was researched for ease of manipulation, radiopacity,

adoption of dentin sealer interphase and flow. They chose the sealer

with best physical properties. A method of triturating and injecting

the cement into the canal was also developed.

In a follow-up Study, Temple group evaluated efficacy of

Ketac- Endo as a sealer, and at the end of 6 months reported that

success and failure rates were comparable.

Their greatest concern was the problem of removal in the

event of retreatment since there is no known solvent for glass

ionomers.

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A Toronto/Israel group reported that Ketac- Endo sealer can be

effectively removed by hand instruments and chloroform solvent

followed by one minute with an ultrasonic No. 25 file.

FORMALDEHYDE CONTAINING SEALERS

A large group of endodontic sealers and cements have

substantial additives of Para formaldehyde. Some of the more

common are Endomethasone, Kri paste, Reblers paste and N2.

Although not much different in content as far as toxicity is

concerned, N2 has been the material most commonly focused on

when discussing the phenomenon. This material is also known as

RC-2B or the “Sargenti technique”. Throughout the years it has

been heavily commercialized. It is difficult to understand the anyone

can subscribe to the idea that treating the apical pulp wound with a

strong tissue coagulating toxic material may enhance healing.

N2 is basically a zinc oxide eugenol sealer. Its composition has

been varied extensively through out the years. The significant

content of lead oxide and smaller amount of organic mercury, that

formerly were major toxic components of N2 are often missing in

recent formulas. However this material still contains large amount of

formaldehyde. It seals well in combination with a core. Because it

contains 6% to 8% Para formaldehyde, it loses substantial volume

when exposed to fluid. It also absorbs more than 2% of fluid during

the 1st week.

N2 is very toxic in experiments in vitro and in animal

experiments. The tissue reaction normally observed is a coagulation

necrosis within a very short time, reaching its maximum in less than

3 days. The coagulated tissue is altered to such an extent that it

cannot undergo any repair for months because it is formaldehyde

impregnated.

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With time the formaldehyde is washed out of the necrotic

tissue, allowing either bacteria to be established in the necrosis or,

if blood supply is adequate, repair to take place. In clinical

applications this untoward tissue reactions can be seen as localized

inflammatory reactions in the periapical tissues.

EXPERIMENTAL SEALERS

1) BISGMA UNFILLED RESIN

At Tufts University, experiments are underway to employ a

BISGMA unfilled resin as a sealer. At present, precipitated silver is

being used as a radiopacifier. However tantalum is planned for the

future. The material might be marketed as Seal Dent – Endo or

Micro seal.

An unpublished leakage study should show over 75% of the

specimen with zero leakage. The new material was found to be

biocompatible but is impossible to remove.

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2) PIT AND FISSURE SEALANTS

Low viscosity resins such as pit and fissure sealants have

been tried as sealers but would not seem suitable as root canal

filling materials.

Close adaptation depends upon smear layer removal, which

was difficult to achieve in the apical third of canal.

3) ISOPROPYL CYANOACRYLATE

At Loma Linda University, isopropyl cyanoacrylate was found

to be more adequate in sealing canals than other commercial

sealers. However further research was discontinued due to lack of

acceptance by U.S. FDA.

4) BARRIER:

A polyamide varnish – Barrier has also been tried as a sealer

but was not found as effective as zinc oxide eugenol.

5) DENTIN BONDING AGENTS:

At the university of Minnesota, the efficacy of 4 different

dentin bonding agents used as root canal sealers was tested.

No leakage was measurable in 75% of the canals sealed with

Scotch bond, 70% sealed with Restodont, 50% sealed with Dental

Adhesive and 30% sealed with GLUMA.

One might even visualize rebirth of the silver point combined

with one of the adhesives as Amalgam bond that adheres to dentin

as well as metals.

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Obstacles faced by bonding agents before they become

endodontic sealers

Preparation of dentin to remove the smear layer is difficult in

the apical third even with NaOcl or citric acid is used with

ultrasonic debridement.

Radiopacity – Radiopaquing metal salts must be added to the

adhesive which will upset the delicate chemical balance that

leads to polymerization.

All bonding agents are very technique sensitive and many do

not polymerize in the presence of moisture of

Hydrogenperoxide.

Placement – The question of a delivery system that will best

ensure a total porosity free placement is a problem.

Removal in the event of failure – These resins polymerize very

hard.

RESINIFYING THERAPY

This was suggested by Chinese has a method of Canal

obturation. They do not carefully debride the canal but rather

remove the pulp or gross necrotic debris with a broach and then

insert a resinfying agent, which is made up of formaldehyde,

aerosol, alcohol, resorcin and NaoH. It sets 5-15 mts in vitro. The

Chinese Claim that the residual pulpal tissues and infected

substances in the canal will become resinified and harmless after

polymerization. They claim a success rate of 84.9% and show rather

healing inspite of the formidable phenolaldehyde antibacterial

formula.

6) CALCIUM PHOSPHATE SEALERS:

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Two dry powders one acidic and one basic are mixed with

water, and injected into the root canal. It sets as hard as enamel

within five minutes.

Tetra calcium phosphate is the basic constituent and the

acidic component is either dicalcium phosphate di-hydrate or

anhydrous dicalcium phosphate. Water is merely a vehicle for

dissolution of the reactants. Setting time may be extended by

adding glycerin to the mixture. Usually mild phosphoric acid solution

speeds up the dissolution of the reactants. Even aliquots of blood

from a surgical site may be substituted for water.

The final set cement consists of nearly all crystalline material

and porosity is a direct ratio to the amount of solvent used. It is as

radiopaque as bone. It is nearly insoluble in water and is insoluble in

saliva and blood. It is readily soluble in strong acids, which may be

considered in the event it must be removed.

SEALER EFFICACY

Hovland and Dumsha probably summarized it best:

“Although all root canal sealers leak to some extent—there is

probably a critical level of leakage that is unacceptable for healing

and therefore results in endodontic failure;

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This leakage may occur at the interface of the denture and

sealer, at the interface of the solid core and sealer and through the

sealer itself or by dissolution of the sealer.

Hence in choosing a sealer, factors other than adhesion must

be considered – setting time, case of manipulation, antimicrobial

effect, particle size, radiopacity, proclivity to staining dissolvability,

chemical contaminant (H2O2, NaOcl) cytotoxicity, cementogenesis

and osteogenesis.

RESUME OF ADHESION:

All presently available sealers leak; they are not impermeable.

But some leak more than others mostly through dissolution. The

greater the sealer/peri radicular interface (i.e.) apical perforations

blunderbuss open apices, the faster dissolution takes place.

Zinc Oxide, Ca (OH2) Type sealers:

In a 2-year solubility study, Peters found that zinc oxide

eugenol sealer was completely dissolved away.

One might think that first lining the canal with varnishes such

as Barrier or Copalite might improve the seal, but neither does.

More recent studies relating to zinc oxide base sealers and

others have found essentially the same: zinc oxide eugenol and Ca

(OH2) solubility.

In spite of their deficiencies, zinc oxide eugenol cements and

their variations continue to be most popular root canal sealers

worldwide. But they are just that, sealers and any attempt to

depend on them wholly or in great part, materially reduces long-

38

term success. That is the principal reason why silver points failed

too little solid core and too much cement in an avoid canal.

If the apical orifice can be blocked principally by solid core

material, success is immeasurably improved over long term, if not

for lifetime.

On the other hand in every study in which obturation without

sealers is attempted, the leakage results are enormously greater

sealers and necessary.

PLASTICS AND RESIN TYPE SEALERS

It seems reasonable to assume that plastics, resins and glues

should be more adhesive to dentin and less resorbable than the

mineral oxide cements. But they have not proved dramatically so: In

one study AH-26 was found comparable to zinc oxide eugenol

sealer.

In another study AH-26 and Diaket were found satisfactory as

sealers along with all the zinc oxide eugenol products. Another

study found Diaket less effective than Tubliseal but better than N2.

Lee Endofill was a efficacious as Grossman’s Sealer.

In a very recent Australian study, however AH-26 was found to

have better sealing capabilities than three other cements, (i.e.)

Apexit, Sealapex and Tubliseal.

As far as the new glass ionomer cement Ketac-Endo is

concerned Ray and Seltzer found it superior to Grossman’s Sealer,

but others found it difficult to remove in retreatment.

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The early leakage reports on the adhesives used

experimentally as root canal sealers are most encouraging. A 1987

report when adhesives were in their infancy, placed Scotch bond

first, with “no leakage measurable in 75% of the canals” and

GILUMA last with 30% showing no leakage.

Adhesives today are in their third and fourth generation far

superior to the initial resins. Also, there are adhesives such as C&B

Metabond or All Bond that actually polymerize best in most

environments.

EXPERIMENTAL CALCIUM PHOSPHATE SEALERS (CPS):

Studies emanating from the ADA Paffenberger center find

calcium phosphate cements very praise worthy, for their sealing

properties, as well as tissue compatibility. In one study they proved

better sealants than a zinc oxide eugenol gutta percha filling.

In another study they found the apatite injectable material

“demonstrated a uniform and tight adaptation to the dentinal

surfaces of the chambers and root canal walls”.

TISSUE TOLERANCE OF ROOT CANAL SEALERS, CEMENTS

AND PASTES.

All the materials used to seal root canals – gutta percha,

silver, the sealers, cements, pastes; plastics irritate periradicular

tissue if followed to escape from root canal. And if placed against a

pulp stump as in partial pulpectomy, they irritate the pulp tissue as

well.

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At present four approaches are being used to evaluate

scientifically the toxic effects of endodontic materials.

1) Cytotoxic evaluation

2) Subcutaneous implants

3) Intraosseous implants

4) Invivo peri radicular reactions.

CYTOTOXIC EVALUATION

Cytotoxic studies are done by measuring leucocytes migration

in a Boyden Chamber by measuring the effect suspect materials or

their extracts have on fibroblasts in culture, or using radioactively

labeled tissue culture calls or tissue- culture agar overlay or a

fibroblast mono layer on a Millipore filter disk. The results are quiet

similar.

According to the studies, almost all of today’s sealers are toxic

to when first mixed, while they are setting over hours, days or

weeks and some continue to age noxious elements for years. This is

of course caused by dissolution of the cement thus releasing the

irritants. For eg. Eugenol is not only cytotoxic but also neurotoxic.

More recently, it has been reported that, the cyto- toxicity of zinc

oxide eugenol may be based on the possible toxic effect of zinc ions.

In testing the toxicity of gutta percha only the pure raw gutta

percha was nontoxic while the gutta percha with zinc oxide showed

toxicity due to release of zinc ions.

As far as cytotoxicity studies are concerned one would have to

rank the pure zinc oxide eugenol sealer as worst- Grossman’s and

Rickert’s followed by Wach’s and Tubuliseal, Sealapex CRS and

finally Nogenol.

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The least toxic of the resins, in fact the least toxic of all the

sealers is Lee EndoFill, followed by AH-26, Diaket.

SUBCUTANEOUS IMPLANTS

Subcutaneous implants of root canal sealers, to test their toxic

effects are done either by needle injection under the skin of animals

or by incision and actual insertion of the product, either alone or in

Teflon tubes or cups. Freshly mixed material may be implanted

allowing it to set in situ or completely set material may be inserted

to judge long term effects.

Tissue implantation ranking of endodontic sealers would again

have to list Lee EndoFill as the least toxic followed by Nogenol, AH-

26, Sealapex, and Tubliseal, CRCS along with Zinc Oxide Eugenol

sealers, would rank higher in Toxicity and formaldehyde cements

rank as unacceptable.

OSSEOUS IMPLANTS

The sealers implanted directly into bone evoke less

inflammatory response than the same cements evoke in soft tissue.

From Marseille comes a report of two zinc oxide eugenol

sealers implanted into rabbit’s mandible. At four weeks both sealer

implants showed “slight to moderate reactions –no bone formation,

or bone resorption.

At 12 weeks there was slight to very slight reactions – bone

formation in direct contact with sealers and bone ingrowth into the

implant tubes.

42

Part of the implanted sealer was absorbed; macrophages were

loaded with the sealer.

In Argentina, Zmener tested glass ionomer cements in dog

tibias and stated that at 90 days “the inflammatory picture had

resolved with progressive new bone formation.

Again, the Para formaldehyde containing cements came off

second best.

There is not enough evidence to rank cements implanted into

bone. However, one must be impressed with the mild to stimulating

reactions that are reported in bone.

IN-VIVO TISSUE TOLERANCE EVALUATION

Most ideal method of testing drug, a substance or a technique

is in vivo in a human subject. But this is often dangerous, costly,

unethical, and so animals are substituted. The closer ones to

Humans are the monkeys.

Erausquin and Muruzabal, working in Buenous Aires performed

the seminal in-vivo research on tissue tolerance to sealers, and

concluded that all commercial root canal sealers are toxic causing

extensive to moderate tissue damage as soon as they escape

through the foramen.

In comparing the various sealers, Erausquin and Muruzabal

found that straight zinc oxide eugenol cement was highly irritating

to the periradicular tissues and caused necrosis of the bone and

cementum. Inflammation persists, for 2 weeks or more. Finally, the

zinc oxide eugenol becomes encapsulated. U.S. National Bureau of

Standards also agreed to this.

43

Erausquin and Muruzabal studied all zinc oxide eugenol based

cements, and concluded that, “All the cements, if the canal was

overfilled showed a tendency to be resorbed by phagocytes.

Grossman’s sealers and N2 both provoked severe

inflammatory reactions and Rickert’s sealer caused moderate

infiltration. Poor debridement and poor filling of the canals however

caused the most severe destruction of the alveolar bone. The least

reaction was found when the canal was not overfilled.

Seltzer and colleagues, after their studies concluded that,

when root canals were filled short of foramen, the reacts tended to

subside within 3 months and complete repair eventually took place.

In contrast, the teeth with overfilled root canals exhibited persistent

chronic inflammatory responses. There was also a greater tendency

towards epithelial proliferation and cyst formation in the overfilled

canals.

Diaket and AH-26, when overfilled showed only mild

inflammation. Diaket, became encapsulated while AH-26 was

resorted.

More recently, Norwegians tested AH-26 against

Endomethasone, Kloropercha and zinc oxide eugenol. At 6 months

they concluded that the periradicular reaction to the endodontic

procedures and to the materials was limited.

On the other hand, the connecticut group found a long term

(2 to 3 yrs) differences ranking AH-26 as mild irritant, ZOE as

moderate and Kloropercha as severe.

44

One must conclude that periradicular tissue reaction to all the

cements will first be inflammatory, but as the cements reach their

final set, cellular repair takes place unless the cement continues to

break down, releasing one or more of its toxic components.

To brief, the reactions shown by various cements in- vivo.

ZINC OXIDE EUGENOL

Inflammation was intensified when the material was extruded

into the periapical tissues. X-ray microanalysis of the dentin

indicated that the zinc from zinc oxide eugenol cement

diffuses into the dentin depending on time and distance.

These kinds of dentin become more resistant to acid

dissolution.

For many years precipitated silver powder was added to zinc

oxide eugenol because of its bacteriostatic properly. Silver

particles penetrate the dentin all the way to the border of and

sometimes into the cementum. The tubules become intensely

stained. Hazard inherent to the use of eugenol is the potential

for sensitization.

The rate of release of eugenol declined with time due to

progressive hydrolysis of the cement surface. The original

release correlated with an initial depression of macrophage

activity.

AH-26

It is well tolerated by periapical tissues. Excess material in the

periapex tunnel to become encapsulated. A few cases

reported paresthesia and neurotoxcity by partially inhibiting

nerve conduction. The inhibition is partially reversible.

45

Normal cell growth and cell manipulation were observed.

Other studies showed moderate to toxicity. It was found to

inhibit leukocyte migration.

DIAKET

Well tolerated by apical and periapical tissues, overfilling

caused no inflammatory reactions and were encapsulated by

fibrous connective tissue.

GIC

Freshly prepared material was found to be toxic to fibroblasts,

macrophages, monocytes and lymphocytes. But the toxicity

tends to decrease after setting.

POLYCARBOXYLATE

Materials produced an inflammatory response when it is

extruded into periapical tissues.

CALCIUM PHOSPHATE

The sealer penetrated and occluded the radicular dentinal

tubules and enhanced hydroxy apatite formation. This

penetrated the dentinal tubules upto 10m.

PARAFORMALDEHYDE TOXICITY

As initially compounded, N2 was a zinc-oxide eugenol cement

congaing 6.5% para formaldehyde as well as some lead and

mercury salts. Concern over lead and mercury transport via the

blood stream to vital organs forced the American producers of the

N2 look alike, RC-2B to drop the heavy metals. But in no way would

they reduce the toxic para formaldehyde from the formula. A myriad

of damaging research paper-in vitro, in vivo, clinical – denouncing

these products, have been published in the last 20 years from all

46

over the world. Pittford found for example, that N2 and

Endomethasone caused a universal ankylosis and root resorption of

dog’s teeth filled, but not overfilled with these toxic products.

A study was conducted but Indiana University using para

formaldehyde and it was concluded that the treated pulps were in

no better shape than the untreated inflammed controls.

NERVE DAMAGE FROM PARA FORMALDEHYDE

If N2 or RC-2B is forced into maxillary sinus or the mandibular

canal, it results in persisting paresthesia. In 1988, Brodin reported

that sealers containing formaldehyde were irreversible unless

surgical treatment was performed.

The tragedy of overfilling into the mandibular canal, especially

with such toxic materials, related to a misconception of the size of

the pulp. Dentists spin more and more material into the canal, far

more than it to takes to fill the space. Fanibunda points out that the

average pulp space of a maxillary central incisor is the size of drop

of water. This entire pulp space, crown and root. The root canal is

only a small portion of this volume.

N2 is now seldom used – probably because of the numerous

reports of its adverse effects and the fact that is not recommended

by dental schools.

47

STUDIES RELATED TO ROOT CANAL SEALERS

1) R. Gerosa, MD. DDS, M. Puttini MD, DDS and G. Caralleri MD,

DDS, Phd, 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 m is non-cytotoxic.

2) 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.

3) An invitro study to evaluate the relative cyto compatibility 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 168hrs 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%.

4) The effect of newly developed root canal sealers on rat dental

pulp cells was assessed by Kokichi Matsumoto and others. It was

concluded that the new sealers were the least toxic in vitro,

compared with five conventional, sealers – AH26, Diaket, Canals,

Tubli Seal and Sealapox.

5) A Comparative study of tissue toxicity of 4 endodontic sealers –

zinc oxide eugenol, Tubliseal, Seal apex and Endoflas F.S. by

Meenu Mittal et al and concluded that no inflammatory response

was seen after 3 months, after injecting the sealers

subcutaneously into rats.

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