1. Root canal filling
materials.
Root filling
techniques.
Lecturer: Levkiv Mariana
Department of Therapeutic
Dentistry
TSMU

2. Purpose of root canal filling
 To prevent bacteria and bacterial elements from
spreading from (or through) the canal system to
the periapical area,
 the fully instrumented root canal has to be
provided with a tight and long-lasting obturation.
 A root canal filling material should, therefore,
prevent infection/reinfection of treated root canals.
Together with an acceptable level of
biocompatibility (inert material) this will provide the
basis for promoting healing of the periodontal
tissues and for maintaining healthy periapical
conditions.

3. Instruments for root canal filling
 Lentulo spiral filler/rotary paste filler
 Function and features
 • Small flexible instrument used to place
materials into the canal
 • Fits into the conventional handpiece
 • Use with caution as it can be easily broken
 • Different sizes available

4. Finger spreader
Function, features and precaution
 • Used to condense gutta percha into the canal
during obturation
 • Finger instrument with a smooth, pointed,
tapered working end
 • Disposed of in the sharps’ container
Varieties
 Can be of the hand instrument type (lateral
condenser)

5. Endodontic plugger
Function
 Working end is flat to facilitate plugging or condensing
the gutta percha after the excess
 has been removed by melting off with a heated
instrument
Varieties
 • Different sizes of working ends are available
 •Available as hand or finger instruments

6.  Gutta percha points
Function and features
 •Non-soluble, non-irritant points that are condensed
into the pulp chamber during obturation
 • Standardised type: follows same ISO classification as
endodontic files
 • Non-standardised: have a greater taper than the
standard ISO type
Varieties
 • Can be packaged in single dose or bulk packages
 • Different sizes with different tapers available

7. OBTURATING MATERIALS
Sealers
 Regardless of the obturation technique
employed, sealers are an essential
component of the process. Sealers fill the
space between the canal wall and core
obturation material and may fill lateral and
accessory canals, isthmuses, and
irregularities in the root canal system.

8. The ideal properties of endodontic sealer are as
follows:
 1. It should be tacky when mixed to provide good adhesion between it
and the canal wall when set.
 2. It should produce a watertight seal
 3. It should be radiopaque so that it can be visualized o on X-ray.
 4. The particles of powder should be very fine so they can mix easily with
the liquid.
 5. It should not shrink on 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 nonirritating to periradicular tissue.
 11. It should be soluble in a common solvent in case removal of the root
canal filling becomes necessary.

9. The most popular sealers are grouped by type:
 Zinc oxide-eugenol formulations,
 Calcium hydroxide sealers,
 Glass- ionomers, and
 Resins.
Regardless of the sealer selected, all are toxic
until they set. For this reason, extrusion of
sealers into the periradicular tissues should be
avoided.

10.  Zinc oxide-eugenol and resin sealers have a
history of successful use over an extended period.
Zinc oxide-eugenol sealers have the advantage of
being resorbed if extruded into the periradicular
tissues .
 Calcium hydroxide sealers were recently
introduced for their potential therapeutic benefits. In
theory these sealers exhibit an antimicrobial effect
and have osteogenic potential. Unfortunately these
actions have not been demonstrated, and the
solubility required for release of calcium hydroxide
and sustained activity is a distinct disadvantage.
 Glass ionomers have been advocated for use in
sealing the radicular space because of their dentin
bonding properties. A disadvantage is their difficult
removal if retreatment is required.

11.  Sealers containing paraformaldehyde are
contraindicated in endodontic treatment.
Although the lead and mercury components
have been removed from the formulations
over time, the paraformaldehyde content has
remained constant and toxic. These sealers
are not approved by the U. S. Food and Drug
Administration.

12.  Controversy surrounds removal of the smear layer
before obturation. The smear layer is created on
the canal walls by manipulation of the files during
cleaning and shaping procedures. It is composed
of inorganic and organic components that may
contain bacteria and their by-products. In theory
remnants left on the canal wall may serve as
irritants or substrates for bacterial growth or
interfere with the development of a seal during
obturation. Although fluid movement may occur in
obturated canals, bacterial movement does not
appear to take place. Recent evidence suggests
that removal of the smear layer can enhance
penetration of the sealer into the dentinal tubules.

13.  Removal of the smear layer can be
accomplished after cleaning and shaping by
irrigation with 17% ethylenediaminetetraacetic
acid (EDTA) for 1 minute. Irrigation should be
followed with a final rinse of sodium
hypochlorite.

14. Acceptable methods of placing the sealer in
the canal include the following:
 • Placing the sealer on the master cone and
pumping the cone up and down in the canal
 • Placing the sealer on a file and spinning it
counter clockwise
 • Placing the sealer with a lentulo spiral
 • Using a syringe
 • Activating an ultrasonic instrument
The clinician should use care when placing
sealer in a canal with an open apex to avoid
extrusion.

15. Core Obturation Materials
 Historically, a variety of materials have been
employed to obturate the root canal, falling
into three broad categories:
 solids,
 semisolids, and
 Pastes(sealers)

16. Sealers
 A wide variety are available. The calcium hydroxide
materials (e.g. Sealapex) or the eugenol-based sealers
(e.g. Tubliseal) are perhaps the safest choice. Some
would advocate the routine use of non-setting calcium
hydroxide paste (Hypocal) as an inter-appointment
medicament.
 Calcium hydroxide This is considered separately,
because it has a wide range of applications in
endodontics due to its antibacterial properties and an
ability to promote the formation of a calcific barrier. The
former is thought to be due to a high pH and also to the
absorption of carbon dioxide, upon which the metabolic
activities of many root-canal pathogens depend. It is
also proteolytic.

17. Indications for the use of calcium hydroxide
include:
 • To promote apical closure in immature
teeth.
 • In the management of perforations.
 • In the treatment of resorption.
 • As a temporary dressing for canals where
filling has to be delayed. In the management
of recurrent infections during RCT.

18. Solid materials
 Silver cones met many of the criteria for
filling materials but suffered from several
deficiencies. The rigidity that made them easy
to introduce into the canal also made them
impossible to adapt to the inevitably irregular
canal preparation, encouraging leakage.
When leakage occurred and the points
contacted tissue fluids, they corroded, further
increasing leakage.

19. Semisolid material
 Gutta-percha, a semisolid material, is the most
widely used and accepted obturating material.
Gutta-percha is a natural product that consists of the
purified coagulated exudate of mazer wood trees
(Isonandra percha) from the Malay archipelago or
from South America.
 Typical composition of gutta-percha cones.

20.  Gutta-percha does not adhere to the canal
walls, regardless of the filling technique applied,
resulting in the potential for marked leakage.
Therefore, it is generally recommended that
gutta-percha (used cold or heated) is used
together with a sealer. For an optimal seal the
sealer layer should generally be as thin as
possible.

21. Root filling techniques
 Solid core techniques
• Single cone
– Simple
– Quick
– Good length control
– Round standard preparation required
• Lateral compaction
– Good length control
– Not one compact mass of gutta-percha
– Time-consuming technique
– Supposed risk of root fracture
 Softened core techniques
• Warm lateral compaction
– Moderate length control
– Time-consuming t chnique
– Heat may damage periodontium
• Warm vertical compaction
– Poor length control
– Sealer extrusion
– Heat may damage periodontium
• Injection-molded gutta-percha
– Quick technique
– Poor length control
– Heat may damage periodontium
• Thermomechanical compaction
– Quick technique
– Poor length control
– Heat may damage periodontium
– Instrument fracture risk
• Core carrier
– Quick technique
– Sealer extrusion
– Gutta-percha may be stripped off carrier in
curvature
– Difficult to remove for retreatment
– In combination with posts, inconvenient
technique
• Chloroform–resin
– Quick technique
– Potential health hazard effects on dental
personnel with long-term
use

22. Root canal filling technique.
Solid core technique
 Single cone
The single-cone technique consists of matching a
cone to the prepared canal. For this technique a
type of canal preparation is advocated so that the
size of the cone and the shape of the preparation
are closely matched. When a gutta-percha cone fits
the apical portion of the canal snugly, it is cemented
in place with a root canal sealer. Although the
technique is simple, it has several disadvantages
and cannot be considered as one that seals canals
completely. After preparation, root canals are
seldom round throughout their length, except
possibly for the apical 2 or 3 mm. Therefore, the
single-cone technique, at best, only seals this
portion.

23.  Cold lateral condensation This is a commonly
taught method of obturation and is the gold standard
by which others are judged.
The technique involves placement
of a master point chosen to fit
the apical section of the canal.
Obturation of the remainder is
achieved by condensation of
smaller accessory points. The
steps involved are:

24.  1. Select a GP master point to correspond with the master apical file
instrument. This should fit the apical region snugly at the working
length so that on removal a degree of resistance or 'tug-back' is felt. If
there is no tug-back select a larger point or cut 1 mm at a time off the
tip of the point until a good fit is obtained. The point should be notched
at the correct working length to guide its placement to the apical
constriction.
 2 . Take a radiograph to confirm that the point is in correct position if
you are in any doubt.
 3. Coat walls of canal with sealer using a small file.
 4. Insert the master point, covered in cement.
 5 . Condense the GP laterally with a finger spreader to provide space
into which accessory points can be inserted until the canal is full.
 6. Excess GP is cut off with a hot instrument and the remainder
packed vertically into the canal with a cold plugger.

25. Sketch showing a cross-sectional cut through a
root canal filled with a master cone and multiple
accessory cones

26.  Warm lateral condensation As above, but
uses a warm spreader after the initial cold
lateral condensation. Finger spreaders can be
heated in a flame or a special electronically
heated device (Touch of heat) can be used.

27. Vertical condensation
 In this technique the GP is warmed using a
heated instrument and then packed vertically.
A good apical stop is necessary to prevent
apical extrusion of the filling, but with practice
a very dense root filling can result. Time
consuming.

28.  Diagram of the warm vertical condensation technique.
 A, After a heated spreader
is used to remove the coronal
segment of the master cone,
a cold plugger is used to apply
vertical pressure to the softened
master cone.
 B, Obturation of the coronal
portion of the canal is
accomplished by adding a gutta
-percha segment.
 C, A heated spreader is used to
soften the material.
 D, A cold plugger is then used
to apply pressure to the
softened gutta-percha.

29.  Thermomechanical compaction This involves a reverse
turning (e.g. McSpadden compactor or GP condenser)
instrument which, like a reverse Hedstroem file, softens
the GP, forcing it ahead of, and lateral to the compactor
shaft. This is a very effective technique, particularly if
used in conjunction with lateral condensation in the apical
region, but requires much practice to perfect.
 Thermoplasticized injectable GP (e.g. Obtura, Ultrafil)
These commercial machines extrude heated GP (70-
160°C) into the canal. It is difficult to control the apical
extent of the root filling, and some contraction of the GP
occurs on cooling. Useful for irregular canal defects, e.g.
following internal root resorption.

31.  Coated carriers (e.g. Thermafil) These are cores
of metal or plastic coated with GP. They are
heated in an oven and then simply pushed into
the root canal to the correct length. The core is
then severed with a bur. A dense filling results, but
again apical control is poor and extrusions
common. They are expensive and difficult to
remove.
 Once the filling is in place the tooth will need to
be permanently restored, provided the follow-up
radiograph is satisfactory. Fillings that appear
inadequate radiographically may be reviewed
regularly, or replaced, depending upon the clinical
circumstances.

32. THE CORONAL SEAL
 Regardless of the technique used to obturate the canals,
coronal microleakage can occur through seemingly well-
obturated canals within a short time, potentially causing
infection of the periapical area. A method to protect
the canals in case of failure of the coronal restoration is to cover the
floor of the pulp chamber with a lining of glass ionomer cement after
the excess gutta-percha and sealer have been cleaned from the canal.
Glass ionomers have the intrinsic ability to bond to the dentin, so they
do not require a pretreatment step. The resin-modified glass ionomer
cement is simply flowed approximately 1 mm thick over the floor of the
pulp chamber and polymerized with a curing light for 30 seconds.
Investigators found that this procedure resulted in none of the
experimental canals showing leakage

33. Thank you for your attention