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Introduction Successful root canal therapy requires complete obturation of the root canal system and thus achieving a compact and hermetic seal at the apical end of the root canal. The current accepted method of obturation of prepared canals employs a solid or semisolid core such as gutta-percha and a root canal sealer gutta-percha has no adhesives qualities to dentin regardless of the obturation techniques used. Therefore root canal sealer with the solid core play a major role in achieving the hermetic seal by filling the accessory root canals, voids, spaces and irregularities and hence reducing the changes of failure of root canal treatment.

Definition : Sealer’s are binding agents used to fill up the gap between root canal and obturating material. It also fill up the irregularities, discrepancies, lateral canals and accessory canals.

Ideal Requirements A suitable root canal cement should be used for filling the dry canal in conjunction with gutta-percha as silver cone.

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The requirements of a good root canal sealer are as follows : 1. It should provide an excellent seal apically and laterally. 2. Should produce adequate adhesion when it sets between filling material and canal walls. 3. Should be radioopaque, so that it can be visualized in the radiograph. 4. Should be non staining. 5. Should be dimensionally stable i.e. should not shrink upon setting. 6. Should be easily mixed and introduced into the root canal. 7. Should be easily removed if necessary. 8. Should be insoluble in tissue fluids. 9. Should be bacteriostatic or atleast discourage bacterial growth. 10. Should be non-irritating to periapical tissues. 11. Should be slow setting to ensure sufficient working time. 12. Should be absorbable when extruded into periapical tissues. 13. Film thickness should be as minimum as possible. 14. It should not be mutagenic or carcinogenic.

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Functions of Sealers 1. Antimicrobial agent : Almost all sealer’s contain antibacterial agent and so a germicidal quality is exerted in the period of time immediately after its use. 2. Binding agent : Since the sealer’s are plastic or semiliquid state when placed in the canal and then harden to a solid consistency, they are able to form a bind between the filling material and the dentinal walls. 3. A filler : It is used to fill the discrepancies between the cone and the canal walls. 4. A lubricant : It is used for lubrication when used in conjunction with semisolid material. 5. Radiopacity : This is an important property since it may disclose the presence of auxiliary canals, resorptive areas, root %, shape of apical foramen.

I. Classification : A wide variety of sealers are available suggesting that the ideal has not yet been discovered. There are numerous classifications of root canal sealer’s : I.

Sealers may be broadly classified according to their composition (Messing).

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i.

Eugenol.

ii. Non-eugenol. iii. Medicated. Among these eugenol containing sealer’s are widely accepted. i. Eugenol

a. Silver containing

i. Kerr sealer (Ricket 1931)

b. Silver free cement

ii. Procosol radioopaque Ag cement (Grossman 1936)

1. Procosol non staining cement (Grossman 1958) 2. Grossman sealer (Grossman 1974) 3. Tubliseal (Kerr, 1961) 4. Wach’s paste (Wach 1925) ii. Non Eugenol These sealers do not contain eugenol and consists of wide variety of chemicals. Eg : - Diaket - AH-26 - Chloropercha + Eucapercha - Nogenol - Hydron - Endofil - Glass ionomer h

- Poly carboxylate i

- CaPO4 cements - Cyanoacrylate

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iii. Medicated These include the gp of root canal cements which have therapeutic properties. Eg: - Diaket – A - N2 - Endomethasone - SPAD - Iodoform paste - Riebler’s paste - Mynal cement - Ca(OH)2 paste (Lanes 1962) - Ca(OH)2 paste (Frank, 1962) (Biocolex) - Endofloss II According to Grossman - Zinc oxide resin cements. - Calcium hydroxide cements. - Paraformaldehyde cements. - Pastes. III According to Clarke - Absorbable - Non-absorbable IV According to Ingle - Cements

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- Pastes - Plastic V According to Harty Pastes and cements may be divided into 5 gps. 1. Zinc oxide eugenol based. 2. Resin cement. 3. Gutta-percha based. 4. Dentin adhesive materials. 5. Materials to which medicaments have been added. Eg: ZnO eugenol. 2. Resin based : Consists of apoxy resin base which sets upon mixing with activator. Eg : AH- 26, Diaket, Hydron. 3. Gutta-percha based : Pastes and cements based on G.P. consists of solution of gutta-percha in organic solvents will known products are : Chloropercha, Eucapercha. 4. Dentin adhesive materials : Adhesive cements have been tested in an attempt to improve the sealing quality of sealers. Eg: - Cyanoacrylate cements - Glass ionomer cements - Polycarboxylate cements - Calcium phosphate - Composite materials. 5. Materials to which medicaments have been added.

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These may be divided into 2 groups 1. Those in which strong disinfectants and antiphlogistic have been added in order to suppress possible post operative pain. The supplemented disinfectant is paraformaldehyde + corticosteroid is used as antiphlogistic – (agents which counteract inflammables). 2. Those in which CaOH has been added with the purpose of inducing cementogenesis + dentinogenesis at the foramen, thus creating a permanent biological seal. Eg. - Parachloroform. - Calcium hydroxide. The most popular commercial calcium hydroxide containing cements are: - Calcibiotic Root Canal Sealer (CRCS) - Sealapex - Biocalex - Individual Sealers Kerr root canal sealer or (Rickert’s formula) -

Based on the cement described by Dixon and Ricket in 1931.

-

This was developed as an alternative to G.P. Sealers – (Chloropercha and Eucapercha sealers) as they lacked dimensional stability.

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Composition : Powder - Zinc oxide - Precipitated silver Oleo resins Thymol iodide

Liquid - Oil of cloves - Canada balsam

34-41.2% 25-30% 30-16% 11-12%

78-80% 20-22%

Advantages : 1. Excellent lubricating properties. 2. Allows working time of more than 30 min when mixed in 1:1 ratio. 3. Germicidal and biocompatibility. 4. Greater bulk than any sealer – thus ideal for condensation techniques to fill voids, auxillary canals + irregularities. 5. Prostaglandin inhibition property – ZnO and Eugenol combined to form zinc eugenolate – prostaglandin inhibitor. (Prostaglandins are mediators of inflammation and sensitize peripheral pain receptors to much or chemical stimulation). Disadvantages : -

Presence of silver makes the sealer extremely staining of they enter dentinal tubules.

-

Indication – Indicated for warm G.P. technique where lateral canals are present.

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Manipulation -

Powder contained in a pellet and liquid in a dropper bottle.

-

1 drop of liquid is added to one pellet of powder – until is obtained.

-

Precipitated silver gives a granular appearances.

-

Completely sets and its inert within 15-30 min, thus decreases inflammatory responses, compared to other cements that take 24-36 hrs to set.

-

Because of the relatively rapid setting of Rickert’s sealer, Grossmans formula appeared in 1936, with the purpose of enveloping a sealer that afforded more working time.

-

Both Rickert’s and Grossman’s formulas were criticized for including silver for radioopacity.

-

Grossmans, formula was subsequently revised in 1958 to exclude silver that is procosol non staining cement.

i. Procosol radiopaque – silver cement (Grossman – 1936) Powder Zn Oxide USP Ppted silver Hydrogenalid resin Magnesium oxide

Liquid Eugenol Canada balsan

45% 17% 36% 2%

ii. Procosol non staining cement (Grossman 1968)

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90% 10%


Powder Zno Staybelite resin Bismuth subcarbonate Barium sulphate

40% 27% 15% 16%

Liquid Eugenol Sweet oil of almond

80% 20%

Grossman Sealer Revised by Grossman in 1974, this is the most advocated sealer because it provides good seal. Composition : Powder Zinc oxide Staybelite resin Bismuth subcarbonate Barium sulfate Sodium borate anhydrous

Liquid Eugenol

40 parts 30 parts 15 parts 15 parts 1 part

5 parts

This sealer is widely used and satisfies most of the requirements for an ideal sealer. Properties : -

Plasticity and low setting time.

-

Good sealing potential and small volumetric change on setting.

-

Zinc eugenate in decomposed by water through continuous loss of eugenol – thus a weak unstable compound.

-

Setting time hardens 2 hours at 37°C.

Disadvantage : Resin is of coarse particle size, and may lodge on the walls of the canal and prevent the root canal filling from seating at correct level.

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Manipulation -

Root canal cement is mixed on sterile glass slab with spatula slab can be sterilized by alcohol scrub and dried.

-

Two or 3 drops of liquid is used and slowly small increments of cement powder is added to the liquid and spatulated to a smooth creamy consistency.

Proper consistency of mix can be tested by 2 methods 1. Drops test. 2. String out test. -

In drop test, the mass of the cement is gathered on to the spatula and held edgewise, the cement should not drop off the spatular edge in less than 1012 seconds. A no.25 reamer as file is rotated in the mass of cement, it is withdrawn and held in a vertical position. A correctly mixed cement should remain with very little movement on the blade of the instruments for 5-10 seconds.

-

In string out test, the mass of the cement is touched with flat surface of the spatula and is raised up slowly from the glass slab. The cement should string out for at least one inch without breaking. Grossman cement is commercially available as procosol non staining

sealer, Roth 801 and Endoseal. Wach’s Sealer (1955) Composition :

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Powder Zinc oxide Tricalcium phosphate Bismuth subnitrate Bismuth sulbiodide Heavy magnesiumoxide

Liquid Canada balsam Oil of cloves

10g 2g 3.5g 0.3g 0.5g

20ml 6 ml

Indications : -

Small curved canals of minimal calibre.

-

In all lateral condensation methods.

-

Contraindicated when heavy lubrications is needed as with short master cone.

Properties : 1. Medium working time. 2. Minimum lubricating quality. 3. Minimal periapical irritation. 4. Sticky, due to the presence of Canada balsam. 5. Increasing the thickness of the sealer lessens its lubricating effect, so this sealer is indicated when there is a possibility of over extension beyond the confines of the root canal. Advantages : 1. It is germicidal. 2. Less periapical irritation. 3. It has light body, thus does not defect small G.P. cones. Disadvantages Odour of liquid Tubliseal (1961)

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Slight modifications have been made in Rickets formula to eliminate the staining property. Marketed as a 2 paste system, base and catalyst. Composition : Base ZnO Bismuth trioxide Thymol iodide Oil + waxes Barium sulphate

57-59% 18.5-21.25% 3.75-5% 10-10%

Catalyst Eugenol Polymerised resin Annidalin

Setting time – 20 min on glass slab. 5 min in the root canal. Advantages : -

Easy to mix

-

Extremely lubricated

-

Does not stain tooth structure

-

It expands after setting.

Disadvantages : -

Irritant to periapical tissues.

-

Working time is less than 30 min, and even shorter in presence of moisture.

Indications : -

When apical surgery is to be performed immediately after filling.

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-

Because of greater lubricatory property, it’s a good choice for use when at becomes deny for a master cone to reach last mm of preparation.

Setting reaction of ZnO eugenol cement Zinc oxide and eugenol sets because of a combination of physical and chemical reactions, yielding a hardened mass of ZnO embedded in a matrix of sheath like crystals of Zn Eugenolate. The percentage of water, particle size of ZnO, the pH and additives are all important factors in setting reactions. Practically all ZoE sealers cements are CYTOTOXIC and irritate on inflammatory response in connective tissue. Tissue culture studies : When applied directly to connective tissue it is cytotoxic. Both the eugenol and ZnO are released from the mixture in to the surrounding tissues. Human studies : -

In humans periapical inflammation has been shown to persist for years after the completion of endodontic therapy.

-

The inflammation is intensified when the material extrudes in the periapical tissues.

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-

Zn from Zinc oxide eugenol cement diffuses into the dentin for at least 0.1mm such dentin may become more resistant to acid dissolution.

Advantages of ZnO eugenol cement : 1. Ease of manipulation 2. Adhesion to the dentinal walls. 3. Radio-opaque with some germicidal properties. 4. Minimal staining. 5. Ample working time. Disadvantages : 1. Irritant to periapex. 2. Not easily absorbed from apical tissue. Kloroperka N-O sealer This formula was suggested by Nyborg and Tullin in 1965. Composition : Powder Canada balsam Resin Gutta-percha Zinc oxide

19.6% 11.8% 19.6% 49%

Liquid Chloroform

The powder is mixed with liquid chloroform, after insertion chloroform evaporates leaving voids. It has been shown to be associated with a greater degree of leakage than other materials.

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Chlorpercha This is a mixture of gutta-percha and chloroform. The technique is improper because of the excessive shrinkage of the filling after evaporation of the chloroform. Indications : -

This technique is useful in perforations and unusually curved canals or canals with wedge formations.

-

It is used in conjunction with well fitted primary cone. Chlorpercha can fill accessory canals and root canals space.

Modified chlorpercha methods : 1. Johnson – Callahan 2. Nygaard – Ostby Johnson Callahan Method : The canal is repeatedly floaded with 95% alcohol and then dried with absorbent patients. It is then floaded with Callahan resin chlorform solution for 2-3 min. A suitable gutta-percha cone is inserted and compressed laterally and apically with a stering matrix of the plugger until the gutta-percha is dissolved completely in the chloroform solution in the root canal. As chloroform evaporates, it shrinks and apical seal is lost.

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Nygaard – Ostby The canal walls are coated with klorperka, the primary cone dipped in sealer is inserted apically. Pushing partially dissolved tip of the cone to its apical seal. FDA (Food and Drug Administrations) has banned the use of chloroform, since it has carcinogenic potential. AH - 26 This is an epoxy resin recommended by Shroeder in 1954 Powder Bismuth oxide Hexameltylene tetramine Silver powder Titanium oxide

60% 25% 10% 5%

Liquid Bisphenol Diaglycidyl ether

The formulation has been altered recently with the removal of silver as one of the constituent to prevent tooth discoloration. Properties : 1. It has good adhesive property. 2. Antibacterial. 3. It contacts slightly while hardening. 4. Low toxicity and well tolerated by periapical tissue. -

It has a exceptionally slow setting cement, setting time is 36-48 hrs at body temperature and 5-7 days at room temperature.

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-

Parasthesia may occur foll the use of AH-26, but partial recovery occurs within 1-2 years.

Tissue culture studies Tests an several cell lines including human epithelial cells, human blood, monocytes and lymphocytes (Nakamura et al 1986) revealed that the material was moderately to severe toxic. Human studies : -

This material was well tolerated by periapical tissues.

-

Excess material in the periodontal ligament tends to become encapsulated.

-

Mandibular parasthesia may occur following the overfilling.

Effectiveness of Sealer : -

It is an effective sealing agent.

-

AH-26 releases formaldehyde, release of formaldehyde increases by 2 fold after 12 hours and 200 times after 98 hrs once the sealer is set the formaldehyde level decreases .

Diaket :

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-

Diaket is a polyvinyl resin, a reinforced chelate formed between zinc oxide and diketane . it was introduced in Europe by Schuffle in 1952.

-

Diaket consists of a fine, pure white powder and a viscous, honey coloured liquid.

-

Diaket hardens rapidly, setting in about 6-8 min on the glass slab.

-

Diaket is known for its resistance to absorption. Stewart found that diaket is superior to other sealers in tensile strength.

-

Diaket produced inflammatory reaction when the canal was overfilled, “mortification” of apical cementum and alveolar bone occurred. Cement is frequently used to cement endosseous implant.

-

Diaket A – Chemically this sealer is similar to diaket but it also contains the disinfectant hexachlorphene. Diaket is one of the few medicated cements which does not contain paraformaldehyde.

Hydron : (Injectable cements) -

Hydron is a rapid setting hydrophilic, plastic material used as a root canal sealer without the use of a cone. This was introduced by Wichterle and Lion (1960).

-

Hydron is a polymer of hydroxy ethyl methacrylate.

-

It is available as air injectable root canal filling material.

-

It is considered to be biocompatible material that conform to the shape of the root canal because of its plasticity, when the material comes in contact with moisture, the gel absorbs water and swells. 19


-

The working time for hydron is 6-8 minutes.

-

Its radiopacity is very low, this complicates the radiographic observation of an overfill.

-

Several investigators have indicated that overfilling with hydron causes long term periapical inflammation so tissue tolerance of hydron is controversial.

KETAC-ENDO (Glass Ionomer Cement) -

Glass ionomers have also been developed for endodontics one of these is presently marketed as Ketac Endo.

-

Glass ionomer cements are reaction product of an ion leachable glass powder and a polyamins in aqueous solution.

-

An setting they form a hard polysalt gel which adhere tightly to enamel and dentine, because of their adhesive qualities, they can potentially be used as root canal sealers.

-

It can be triturated and injected in the root canal.

Advantages : 1. It has best physical qualities. 2. Best bonding to dentin. 3. Few voids. 4. Low surface tension.

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Disadvantages : -

It cannot be removed from the root canal is the case of retreatment.

Nogenol : Nogenol was developed to overcome the irritating quality of eugenol, it has been advocated as a less irritating sealer. It was found that after 24 hrs all sealers showed considerable inflammation. At 96 hrs nogenol was considerably less irritating than other sealers. -

Nogenol expands on setting and improves its sealing efficacy with time.

-

Base – ZnO with barium sulfate as radioopacifies. Accelerated by resin methyl abitable, lubric and salicyclic acid.

Poly carboxylate cements : It consists of modified zinc oxide powder and as aqueous solution of polyacrylic acid. The cement has chelating action, bonding to both enamel and dentin. Because of its adhesive and antibacterial properties, the cement has been tested as a root canal sealer. Apical seal is found to be inferior to other sealers. Advantages :

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1. It bonds well to dentin. 2. Antibacterial property. 3. Compounds like fluoride and calcium hydroxide can be added. Disavantages : 1. Special plastic plugger is required for insertion since it has great adhesiveness to steel instruments. Cyanoacrylate cements : Cyanoacrylate cements are composite type polymers that can be polymerized to hard products by the use of basic inorganic material that also serves as filter. They have been reported to be biocompatible. Calcium phosphate : Brown (1983) showed that calcium phosphate cement penetrated and occluded the radicular dentinal tubules and enhanced hydroxyapatite formation. Wefel (1984) found that it effectively plugged the apical foramen and penetrated the dentinal tubules up to 10mm. The biocompatibility of this cement in endodontic therapy has not yet been established. III. Medicated Cements : Example:

Riebler’s paste Mynal cement Iodoform paste Endomethasone

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N2 Calcium hydroxide paste Diaket A Riebler’s paste Powder Zn oxide Formaldehyde Barium sulfate Phenol

Liquid Formaldehyde Sulfuric acid Ammonia Glycerine

Mynol cement : Powder Zn oxide Iodoform Resin Bismuth

Liquid Eugenol Creosol Thymol

subnitrates These materials are usually used without cone materials, hence they are introduced into the root canal by means of either a lentulospiral or some type of injection device. N2 : N2 was introduced by Sargenti and Ritcher (1961), N2 refers to the so called second nerve (pulp is referred to as Ist nerve) For some years 2 different types of N2 sealers were available : a. N2-Normal – Used for root filling. b. N2-Apical – Used for antiseptic medication of canal.

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Recently N2-‘Universal’ a cement containing the features of both N2Normal and N2-Apical has been introduced. The formula has been cultured by removing hydrocortizone, prednisolone and barium sulfate. Composition of N2-Universal

Radioopacifiers Adhesion Antiseptic

Powder Zinc oxide Lead tetroxide Paraformaldehyde Bismuth subcarbonate Bismuth subnitrate Titanium dioxide Phenyl mercuric borate

68.51g 12g 4.7 2.60g 3.7g 8.4g 0.09 g

Liquid Eugenol CleumRosea Cleum Lavandular

Toxicity : Degree of irritation is severe when overfilling with N2 is forced into the maxillary sinus or mandibular canal persisting paraesthesia was observed. Blood lead level is increased after the insertion of root filling. Effectiveness of sealers : Apical seal with N2 is better when compared to procosol, nogenol, tubliseal and diaket.

Endomethasone : The formation of this sealer is very similar to N2 composite. Powder Zn oxide Bismuth subnitrate

100g 100g

Liquid Eugenol

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Dexamethasone Hydrocortisone Thymol iodide Paraformaldehyde

0.019g 1.6g 25.0g 2.20g

A pink antiseptic powder is mixed with eugenol sometimes endomethasone root canal sealers give rise to pain or discomfort after 6-8 weeks of insertion. This occurs because corticosteroids marks any inflame reaction until it is removed from the area. SPAD : This material is advertised as a one visit non irritant radioopaque filler and sealer. It is a resorcinal formaldehyde resin supplied as a powder + liquid. Powder ZnO Barium sulfate Titanium dioxide Paraformaldehyde Hydrocortizone acetate Calcium hydroxide Phenyl mercuric borate -

72.9g 13.0g 6.30g 4.70 2.00g 0.44g 0.16g

Liquid (Clear) Formaldehyde Glycerine

57.0g 13.0g

Liquid (Red) Glycerine Resorcinal Hydrocloric acid

55g 25g 20g

Equal parts of the 2 liquids are mixed with the powder. The essential reaction to form the resin is between the resorcina and the formaldehyde.

-

Setting time of SPAD is 24 hrs.

Indications : 1. Pulpotomies in both deciduous and permanent teeth. 2. For treatment of acute endo infection. 3. Teeth with periapical areas. Calcium hydroxide cement :

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-

Calcium hydroxide has been used in endodontics as a root canal filling material, or as a sealant in conjunction with solid core materials.

-

Pure CaOH powder can be used or it can be mixed with normal saline solution. PH- 12.3-12.5.

-

The use of CaOH paste is based on the assumption – there is formation of hard structure or tissue at the apical foramen.

i.

The alkanity of CaOH stimulates the induction of mineralized tissue. Sealapex : (Kerr) It has been described as non eugenol calcium hydroxide polymeric resin

root canal sealer. It is delivered as paste to paste in collapsible tubes. Composition : Base – ZnO with Ca(OH)2, butyl benzene, sulfonamide and zinc stearate. Catalyst – Barium sulfate, titanium dioxide as radioopacifiers with proprietary resin, isobutyl salicylate and a crocil R 972. -

In 100% humidity, it takes 3 weeks to reach a final set. It means sets in dry atmosphere.

-

In expands while setting, healing is more advanced.

CRCS (Hygienic) 1982 :

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CRCS, termed the calcibiotic root canal sealer was the first of the calcium hydroxide based sealer. Composition : Powder Zinc oxide Hydrogenated rosin Barium sulfate Calcium hydroxide Bismuth subcarbonate -

Liquid Eugenol Eucalyptol

CRCS is a zinc oxide eugenol eucalyptol sealer to which CaOH has been added for its osteogenic effect.

-

The difference between the 2 sealers is that CRCS consists of a powder liquid combination, where as sealapex is in the form of 2 paste preparation.

-

CRCS takes 3 days to set fully either dry or humid environment.

Biocalex : Biocalex originally developed and introduced by Bernard (1952). Powder Heavy calcium oxide Zinc oxide

Liquid Glycal Water

-

Powder and liquid are mixed to form a paste.

-

Progressively expands to more than 6 times its original volume.

-

So it is not necessary to prepare the root canal prior to root canal filling.

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-

Calcium oxide and water react within the tooth to form the calcium hydroxide which ionizes to release OH ions.

-

These OH ions decomposes necrotic pulpal tissue to form water and carbondioxide.

IODOFORM Paste : -

Iodoform alone or in combination with other substances has been used as a sealer with core materials.

-

It was described by WALKHOFF (1928) -

60 parts iodoform

-

40 parts solution – 45% parachlorophenol – Camphor

Antiseptic medication

– 6% Menthal Commercially the preparation is known as Kri-1 paste. Iodoform paste stimulates the periapical tissues and excess accelerates bone formation. Disadvantages : 1. Periapical irritation during construction of post crown. 2. Discolouration. Toxicity of Parachloraphenol :

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-

Percent aqueous parachloraphenol solution evakes a very mild connective tissue inflammatory response.

-

Camphorated parachloraphenol is a highly toxic preparation capable of causing tissue necrosis.

Endofloss : Powder ZnO CaOH Iodoform Barium sulfate

Liquid Eugenol Paramonochlorophenol

Application of a sealer : -

Root canal cement may be placed in the canal either by lentulospiral or reamer.

-

When the spiral is termed clockwise by either the fingers on the handpiece, it carrier cement apically.

Reamer : -

To carry the cement apically in the canal a counter clockwise turn is given to the reamer.

-

One size smaller than the last instrument used for enlargement is selected.

-

A small amount of cement is then gathered on the balde of the instrument and caused up the canal and is rotated counter clockwise as it is withdrawn.

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-

Spinning the sealer in to the canal, then is slow gentle pumping action, combined with a lateral rotatory motion of the instrument

is used

thoroughly to the canal wall.

RECENT DEVELOPMENT As a biological root canal sealing agents, bone powder, dentin slices, calcium hydroxide or its products have been attempted so far. -

Bone powder and dentin slices were difficult to purchase and the amount to the obtained, immunological reactions occurred when applied in living body, the CaOH was resorbed by living body without setting.

-

Recently inorganic agents which have compatibility with biological tissues, the BIOCERAMICS, have been developed focused mainly on apatite type agent calcium phosphate especially hydroxyapatite. Recently several root canal sealers composed of hydroxyapatite and

related tricalcium phosphate (TCP) have been promoted. -

Appear to be more biocompatible.

-

Effective in healing mechanical perforation of pulp chamber floor.

-

Pulp capping.

-

Enhancement of bone fill after periapical surgical procedure.

Tricalcium based Sankin Apatite root canal sealer 1. Sankin – Apatite Type I (Vital pulpectomy) -

Powder – 80% 2

– tricalcium phosphate.

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Liquid

-

20% hydroxyapatite

-

25% polyacrylic acid

-

75% water

2. Sankin Apatite Type II (Infected root canals) Powder 56% 2 tricalcium phosphate 14% hydroxyapatite 30% iodoform

Liquid 25% polyacrylic acid 75% water

3. Sankin Apatite Type III (Partially vital) Powder 80% 2 tricalcium phosphate Hydroxyapatite 5% iodoform 1% bismuth subcarbonate -

Liquid 25% polyacrylic acid 75% water

Studies revealed that Type II and Type III were more biocompatible probably due to the presence of iodoform.

-

Recently – Dentsply / Detrey developed a new formulation of AH-26, AHplus which according to manufactures displays better technical and clinical characteristics.

-

Dentsply / Maillerfer – also introduced an epoxy resin sealer, named TOPSEAL with the same formulation as AH-Plus.

AH-Plus Epoxide paste Epoxy resin Calcium tungstate Ziracanium oxide aerosil Iron oxide

Amine paste Adamanthans amine N,N Didenyl – 5 – oxananone diamond T-C-D diamonds Zircanium oxide

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Aerosol Silicone oil Studies by Geromichalor et al have shown that 24 and 48 hrs results showed that AH-26 had for greater cytotoxic effect compared to AH-Plus and topseal.

Conclusion Root canal sealers along with the solid core play a major role in achieving the hermetic seal by filling the accessory canals, voids, spaces and irregularities. Many studies were conducted which concluded that the sealer was essential for effective obturation. Yoynes and Hembree showed that a canal filled with a combination of gutta-percha and sealer achieved more successful seal that either gutta-percha or sealer alone. Each one of the sealer has its own merits and demerits. Zincoxide eugenol is the most commonly used sealer, this was the standard sealer in many studies for comparing with other sealers.

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Many of the other sealers like glass ionomer, AH-26, life, diaket, hydron etc have tested for their sealing efficiency but none of them have showed cent percent results. Current research on inorganic agents, which have the compatibility with biological tissue, the bioceramics i.e. hydroxyapatite sealers have been encouraging results.

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