DR. N. UDAYA BHASKER
Requirements for an Ideal Root Canal-Filling Material
According to Grossman, an ideal root canal-filling material should:
Easy manipulation with ample working time
Have dimensional stability
Be able to seal the canal laterally and apically
Not irritate periapical tissues
Be impervious to moisture and nonporous
Be unaffected by tissue fluids and insoluble in tissue fluids: not corrode or
Not discolor the tooth structure
Be sterile or easily and quickly sterilizable
Be easily removed from the canal, if necessary.
Materials used for Obturation
Core obturating materials
ii. Resin based
iii. Glass ionomer based
iv. Ca(OH)2 based
Gutta percha [Regular/ β phase]
Thermoplasticised [α phase]
ii. Carrier based
Gutta-percha polymer is a trans-1,4-polyisoprene, obtained from the coagulation of
latex produced by trees of the Sapotaceae family
It exists in two crystalline forms (alpha and beta) with differing properties. Another
unstable form (γ) exists, which is amorphous in nature.
In beta phase the material is a solid mass that is compactable, when heated the
material changes to alpha phase that is pliable and tacky and can be made to flow
Composition of commercial gutta-percha
Waxes or resins
(barium or strontium)
The advantages of gutta-percha as a filling material are
1. It is compactible and adapts excellently to the irregularities and contour of the
canal by the lateral and vertical condensation method.
2. It can be softened and made plastic by heat or by organic solvents (eucalyptol,
chloroform, xylol, turpentine).
3. It is inert.
4. It has dimensional stability; when unaltered by organic solvents, it will not shrink.
5. It is tissue tolerant (nonallergenic).
6. It will not discolor the tooth structure.
7. It is radiopaque.
8. It can be easily removed from the canal when necessary.
9. Recent studies have demonstrated that, in vitro, gutta-percha has activity
against several different bacterial species (Staphylococcus aureus, Streptococcus
mutans, S. pyogenes). They have also hypothesized that the active antibacterial
element of gutta-percha cones is probably zinc oxide.
9. It is also readily sterilizable, since immersion in 5.25% sodium hypochlorite for
as little as 60 seconds suffices to eliminate even the most resistant spores
The disadvantages of gutta-percha as a filling material are as follows:
1. It lacks rigidity. The smallest, standardized gutta-percha cones are relatively more
difficult to use unless canals are enlarged above size no. 25.
2. It lacks adhesive quality. Gutta-percha docs not adhere to the canal walls;
consequently, sealer is required. The necessary use of a cementing agent introduces
the risk of using tissue-irritating sealers.
Gutta percha does not bond to any sealers
It can be easily displaced by pressure
5. Gutta percha is almost wholly dependent on a coronal seal to prevent the apical
migration of bacteria if it's challenged by coronal leakage.
CURRENT FORMS OF GUTTA-PERCHA AVAILABLE
Solid core Gutta-percha points
Thermo mechanical compactible
Thermo plasticized Gutta-percha
- Solid core system
Gutta percha is supplied as:
used to check the vitality of teeth
used as a temporary filling
used for obturation
tracing of sinuses
Syringe material :
Obtura II is a heated-gun system, whereby guttapercha sticks are placed within a chamber in the
gun, and a plunger is used to express the heated,
flowing gutta percha through replaceable injection
tips. The flow of the gutta percha is controlled
through the temperature of the unit - the higher
the temperature, the easier the flow. By design,
the system is considered a "high heat" system
Ultrafil uses a pre-dosed cannula system. Cannulas containing various types of
gutta percha are placed in a heating unit. When needed they are loaded into a
gun (similar to a periodontal ligament injection unit), which expresses gutta
percha from the cannula. The system is characterized as a "low-heat" unit, since
the temperature needed to plasticize the gutta percha is much lower than the
Obtura II system
Coating on metal or plastic cores :
It consists of a plastic core coated with alpha phase gutta-percha and a
heating device that controls the temperature.
The carrier is set to the
predetermined length using the millimeter calibration markings on the carrier
shaft. After heating it, the clinician has approximately 10 seconds to retrieve and
insert it into the canal, without rotating or twisting it. The gutta-percha is allowed
2 to 4 minutes to cool before resecting the carrier.
An advantage to this technique is the movement of gutta-percha into lateral and
accessory canals; however, extrusion of material beyond the apical extent of the
preparation is a disadvantage.
SimpliFill uses a flexible, stainless-steel shaft to hold a 5 mm long cone of gutta
percha called the Apical GP Plug. Once the 5 mm Apical GP Plug is firmly
condensed in the apical third of the canal with sealer, the SimpliFill handle is
turned counter clockwise, allowing the carrier to be removed. Leaving only the
Apical GP Plug (no carrier) allows for easy retreatment, should it become
Thermomechanical Compaction of Gutta-percha:
A totally new concept of heat softening and compacting gutta-percha
was introduced by McSpadden in 1979. Initially called the
McSpadden Compactor, the device resembled a reverse Hedstroem
file, or a reverse screw design. It fit into a latch-type handpiece and
was spun in the canal at speeds between 8,000 and 20,000 rpm. At
these speeds, the heat generated by friction softened the gutta-percha
and the design of the blades forced the material apically.
Microseal Condenser : is used in conjunction with heat-softened, alpha
phase-like gutta-percha as well as regular gutta-percha points.
To obturate a canal, the clinician is advised to place the primary gutta-percha
point, followed by the appropriate size Condenser, which has been coated with
the heat-softened gutta-percha. The Condenser is spun in the canal with a
controlled speed handpiece at 1,000 to 4,000 rpm to form a firmer core. This
“flings” the gutta-percha laterally and vertically
Titanium carriers coated with alpha-phase gutta-percha comes in four sizes
and operates in regular slow-speed handpiece.
Friction plasticizes gutta-percha.
Titanium core may be severed and left or removed while still spinning
Gutta Percha Sealers:
GP sealers are prepared by dissolving gutta-percha in solvents like chloroform,
eucalyptol, xylol etc., as well as in rosin and balsam –
Kloropercha : contains balsam, rosin, and zinc oxide in addition to gutta-percha and
Medicated Gutta Percha:
The iodoform, tetracycline and iodoform/tetracycline combination are bound
within the gutta percha points. They act as a reservoir of antimicrobial that is capable
of diffusing onto the surface of the gutta percha thereby inhibiting the colonization of
bacteria on the gutta percha points and within the root canal system. Tetracycline is
capable of coalescing within the dentinal tubules to inhibit long term microbial
growth. These medicated gutta percha points are site specific, surface acting
antimicrobial gutta percha points.
Calcium hydroxide containing Gutta percha:
Gutta percha with high content of Calcium hydroxide (40-60%)
Chlorohexidine Diacetate containing gutta percha :
GP matrix embedded with 5% chlorohexidine diacetate
Used primarily as Intracanal Medicaments.
Silver points :
Introduced by Jasper In 1941,
silver cones were the most widely used solid-core
metallic filling material, although points of gold,
iridioplatinum, and tantalum are also available
Can be used in narrow and curved canals
Silver has more rigidity than gutta-percha and hence
can be pushed into tightly fitting canals and around
curves where it is difficult to force gutta-percha.
Silver points/cones have a circular cross section unlike the canals which may
be oval hence a poor lateral seal
Show high levels of corrosion especially due to the dissolution of the sealers.
Retreivability is difficult
Paste-type filling materials
Include zinc oxide-eugenol cements with various additives, epoxy resins (AH-26),
acrylic, polyethylene, and polyvinyl resins (Diaket), calcium hydroxide
IDEAL REQUIREMENTS OF A ROOT CANAL SEALER
1. It should be tacky when mixed to provide good adhesion between it and the
canal wall when set.
2. It should make a hermetic [sic] seal.
3. It should be radiopaque so that it can be visualized in the radiograph.
4. The particles of powder should be very fine so that they can mix easily with the
5. It should not shrink upon setting.
6. It should not stain tooth structure.
7. It should be bacteriostatic or at least not encourage bacterial growth.
8. It should set slowly.
9. It should be insoluble in tissue fluids.
10. It should be tissue tolerant, that is, non-irritating to periradicular tissue.
11. It should be soluble in a common solvent if it is necessary to remove the root
12. It should not provoke an immune response in periradicular tissue.
13. It should be neither mutagenic nor carcinogenic.
The root canal sealer acts as
a binding agent to cement the well-fitted primary cone into a canal [ much as
zinc phosphate cement binds a well-fitted inlay into a cavity preparation]
a filler for the discrepancies between the cone and the canal walls, and
a lubricant to facilitate the seating of the primary cone into the canal.
Endodontic sealers can be broadly classified into :
Zinc oxide Eugenol based
Calcium hydroxide based
Glass ionomer based
oil of clove
It is germicidal, has excellent lubricating and adhesive qualities, and sets in about half
Because of its silver content, Rickert's sealer may cause discoloration of tooth
Grossman's Formulation [Roth’s Sealer]:
In 1958 Grossman recommended a nonstaining ZOE cement as a substitute for
Zinc oxide, reagent
Sodium borate, anhydrous
Considered standard by which other cements are measured because it reasonably meets
most of Grossman’s requirements for cement
All ZOE cements have an extended working time but set faster in the tooth
than on the slab because of increased body temperature and humidity
Zinc oxide eugenol has the disadvantage, however, of being decomposed by
water through a continuous loss of the eugenol. This makes ZOE a weak,
unstable material and precludes its use in bulk, such as for retrofillings placed
apically through a surgical approach
Other Zinc oxide Eugenol based sealers :
Kerr Pulp sealer:
The Rickerts sealer was reintroduced in 1951 as kerr pulp sealer. It has the same
composition as Rickert’s
Disadvantage : staining of the tooth
Pulp Canal Sealer EWT [Extended working time ]
This sealer is packaged in two collapsible tubes containing a base and an
accelerator, which when mixed together in equal amounts form a creamy mix
Advantages: Non-staining, quick and easy to mix, good radiopacity
Disadvantages: reduced working time in the presence of moisture, expands
Zinc oxide Non-eugenol based sealer [NOGENOL]
Developed to overcome the irritating quality of Eugenol
Formaldehyde containing sealers:
These sealers constantly release antimicrobial formalin.
introduced by Sargenti in 1954 . Also called Sargenti’s Paste
Phenyl mercuric borate
Good antibacterial effect
Irreversible damage to the nerve tissue
Causes coagulation necrosis of the tissues
Other Formaldehyde containing sealers are:
1. RC2B [ American counterpart of N2 sealer]
4. Riebler’s paste
Resin based sealers:
Introduced by Schmidt
A resin-reinforced chelate formed between zinc oxide and diketone, is known
for its high resistance to absorption.
Advantages: good adhesion, sets quickly in the root canal, low solubility and
good volume stability, superior tensile strength
Disadvantages: highly toxic, non resorbable and forms fibrous encapsulation if
Introduced by Schroeder 1957
It is an epoxy resin based sealer
Bisphenol diglycidyl ether
As AH-26 sets, traces of formaldehyde are temporarily released, which
initially makes it antibacterial.
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
Has strong adhesive properties
Disadvantages: slight contraction while setting,
delayed setting, staining
Available as two paste system
Advantages over AH-26
new amines added to maintain the natural color of the tooth
half the film thickness
shorter setting time of 8 hrs,
Epiphany Root canal Sealer
Is a dual cure , hydrophilic resin sealer
Used with Resilon core materials
Dispensed from a double barrelled, automix syringe
Originally it was used along with Epiphany Self-Etch Primer
Now available as Epiphany Self-Etch Sealer [eliminates the priming step]
The system consists of three parts:
1. Resilon – a thermoplastic synthetic polymer-based (polyester) root canal filling
material, as the major component;
2. Epiphany sealer – a resin-based composite that forms a bond to the dentin wall
and the core material under chemical reactions and halogen curing light; and
3. Primer - which prepares the canal wall to get in contact with Resilon and the
Calcium hydroxide based sealers:
The two most important reasons for using calcium hydroxide as a root-filling
stimulation of the periapical tissues in order to maintain health or promotehealing and
for its antimicrobial effects
CRCS (Calciobiotic Root Canal Sealer)
Is essentially a ZOE/eucalyptol sealer to which calcium hydroxide hasbeen added for
its called osteogenic effect.
CRCS takes 3 days to set fully in either dry or humid environments.
It also shows very little water sorption.
This means it is quite stable, which improves its sealant qualities, but brings into
question its ability to actually stimulate cementum and/or bone formation. If the
calcium hydroxide is not released from the cement, it cannot exert an osteogenic
effect, and thus its intended role is negated
It is a zinc oxide based calcium hydroxide sealer containing polymeric resin
Available as two paste system
Extruded material resorbs in 4 months
Good therapeutic effect
Long setting time
Absorbs water while setting and expands
Poor cohesive strength
Available as a two paste system
Better seal than that provided by sealapex
Glass ionomer based sealers:
Chemical bonding with the root dentine, hence strengthens the root
Less technique sensitive
Extruded sealer is highly resistant to resorption [ delayed resorption]
Retrievability is difficult
Heat sources during obturation with gutta percha:
Touch N Heat
Elements Obturation Unit
The SybronEndo Elements Obturation Unit (EOU) is a thermoplastic gutta
percha/RealSeal injector with backfill, down-pack, cautery and hot-pulp testing