In this lecture I explain the basic concept of root canal filling or what called obturation. The lectures discuss different techniques used in that matter in step-by-step fashion and explanatory pictures. It is directed to the level of undergraduate mind.

1. Objectives of Obturation
When to Obturate?
Smear Layer
Obturation Materials
Gutta-Percha Obturation
Cold Lateral Compaction Technique
Solving some problems in Lateral Compaction
Heat-softened gutta-percha techniques
Warm Vertical Compaction
Rotating condenser technique
Precoated carrier
Injection delivery systems
Solvent-softened gutta-percha
Sealers
OBJECTIVES OF OBTURATION
1. To prevent microorganisms which remain in the
root canal after preparation from proliferating and
passing into periapical area
2. To seal the pulp chamber and root canal system
from outer oral environment
3. To prevent passage of periapical exudate and mi-
croorganism to the canals system
4. To prevent gingival microorganism from passing
into the root canals via lateral canals.
WHEN TO OBTURATE?
The decision of single visit or multi-visit endodontic
treatment is controversial. However, Teeth with no sign
of apical periodontitis can be treated in single visit.
While it is preferred to treated symptomatic teeth with
apical periodontitis in several visits, with placement of
intracanal medicament such as calcium hydroxide.
Tooth can be obturated when:
• There is no pain or swelling
• No sign of sinus, fistula or abscess
• The canal is dry and free from necrotic tissue or
pus.
SMEAR LAYER
It consist of organic and inorganic components, that
found on the root canal walls after instrumentation.
The current research emphasis on removal of smear
layer using 17% EDTA or other chelating agents.
OBTURATION MATERIALS
The ideal properties of an obturating material are:
• Biocompatible
• Dimensionally stable
• Capable of sealing the canal laterally and apically
Obturation of root canal
Osama Asadi, B.D.S, Published for Iraqi Dental Academy Blog
In modern endodontics, cleaning and preparing root canal system is more important than filling it, which is
also important. Obturation of root canal serves two purposes: first, to prevent microorganism from entering
root canal second to isolate the remaining microorganism in root canal system from outer tissue fluids and
nutrients sealing of the tooth, with base and restoration, is equally important.
LECTURE OUTLINE
CHAPTER
1
Figure 1. an images shows treated dentinal wall after application of
chelating agent. Notice the opened dentinal tubules that are ready to
.be filled with sealer

2. • Unaffected by tissue fluids and insoluble
• Bacteriostatic
• Radiopaque
• Easily removed from the canal if necessary.
• Do not stain the tooth
The available obturation materials are:
• Gutta-percha
• MTA
• Hydrophilic polymer
• Resilon
Outdated materials are:
• Silver points
• Paste Fillers (Paraformaldehyde, resorcinol, etc..)
Gutta-percha is the most commonly used one, and its
procedures will be described here.
GUTTA-PERCHA OBTURATION
Gutta-percha is a natural rubber obtained from topical
trees of the sapotaceae family.
Gutta-percha points consists of:
• Gutta-percha 20%
• Zinc oxide 59%
• Various waxes, coloring agents, antioxidants, and
metal salts to provide radiopacity
Properties of gutta-percha points:
• Inert (biological inactive)
• Dimensionally stable
• Non-allergenic
• antibacterial
• Radiopaque
• compactable
• Softened by heat
• Softened by organic solvents
• Removable when needed
Methods of filling root canal with gutta-percha can
be classified into three groups:
1. Cold gutta-percha
2. Heat-softened gutta-percha
3. Solvent-softened gutta-percha
COLD LATERAL COMPACTION TECHNIQUE
This technique is taught and practiced throughout the
world. It is the technique of choice for many clinicians.
And it is fast and easy technique. After canal prepara-
tion, master cone that matching the size of master api-
cal file is used to fill the canal. Then accessory points
are compacted laterally using finger or hand spreader.
Procedure in detail:
• Irrigate the canal and dry
• Select a master cone that is the same size as the
master apical file
• Set a mark on master cone to the working length
• Dip master cone into the sealer and coat the canal
wall using up and down motion
• Now insert the master cone to the full working
length. It should have a tug back (resistance on
withdrawal. If not, cut 1 mm from the tip and rein-
sert, or choose larger gutta-percha point)
• Select a finger spreader that reach to the full work-
ing length to the apical stop
• Place spreader alongside the master point and
compact using firm apical pressure only.
• Leave the spreader in place for 3 seconds (to
create deformation in the gutta-percha)
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3. • Select accessory points and dip them into the sealer
and insert them alongside master cone.
• Use spreader to compact accessory points laterally.
• Repeat this procedure by adding more accessory
points until the canal can not take any more points.
• Cut excess gutta-percha using heated plugger.
• Place Resin-modified glass ionomer cement and
apply final restoration
• Take a periapical radiograph for follow-up
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Figure 2. Lateral compaction under the microscope.
Notice the laterally compacted cone

4. SOLVING SOME PROBLEMS IN LATERAL
COMPACTION
Gutta-percha cone reach the working
length but it is loose
Sometimes there are some gutta-percha cones that are
malsized. It is a manufacturing error. So try another
.gutta-percha of the same size
• If that did not worked, then Cut 1 mm from the
tip of the cone with sharp instrument and reinsert
again. This increase the tip diameter.
• Or select a one size larger gutta-percha cone.
Gutta-percha cone passes beyond
working length
This either results from improper apical stop, or gut-
ta-percha cone is small. If apical stop is not prepared
well enough, then you either can re-prepare the canal
with larger instruments until apical stop is created, or
remove 1 mm from the tip of the canal until the cone
fits the canal.
Gutta-percha does not reach the
working length
It is the most common situation. It can occur due to
several reasons:
• The gutta-percha cone is larger than expected, due
to manufacturing errors. In this case select a cone of
the same diameter and try
• Or the canal was not prepared well enough. Use
master apical file and prepare the canal until the file
is loose.
• Blockage of the canal. This can results from insuf-
ficient irrigation of the canal with copious sodium
hypochlorite. Blocked canals are difficult to clean.
Recapitulation with small files and passive ultra-
sonic irrigation might help.
HEAT-SOFTENED GUTTA-PERCHA TECH?
NIQUES
When heat softened gutta-percha compacted into the
canal, it can flow in the lateral canals, fins and ramifica-
tions. This result in superior obturation quality.
Heat-softened GP techniques are divided into two
subgroups:
• Intracanal heating techniques: it involves heating
gutta-percha inside root canal
1. Warm Vertical Compaction (Touch N’ heat, System
B)
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2. Rotating Condenser (Gutta-Condenser)
• Extracanal heating techniques: it involves heat-
ing gutta-percha outside the root canal
1. Precoated carriers (Thermafil)
2. Thermoplastic delivery systems (Obtura III)
WARM VERTICAL COMPACTION
Also known as schilder’s technique, and continuous
wave of compaction technique (with some modifica-
tions). This technique is considered the gold standard
for endodontic obturation. It is particularly useful in
situations such as internal resorption, C-shaped canals,
and those with fins and webs.
In summary, a non-standradized gutta-percha cone is
fitted into the canal. Using a selected plugger (that fits
to the working length minus 5-7 mm) heat is applied
to the gutta-percha, cooled, and then compacted api-
cally. Then the rest of the canal either filled with the
same technique or filled with back-filling (injectable
gutta-percha technique).
Procedure in detail
• Fit a gutta-percha cone and mark it at the working
length
• System-B will be used to heat gutta-percha cone in-
side the canal
• Select one of the system-B pluggers that fits in the
canal 5-7 mm short of the working length. Set a
rubber stop at this level.
•

5. 5
• Also select a conventional plugger to fit to the same
distance
• Dry the canal with paper points
• Apply thin layer of sealer to the apical part of the
cone, then insert it inside and coat the wall with
sealer by up and down movement.
• Insert gutta-percha cone to the full working length.
• Set temperature in System-B to 200 Celsius and cut
the coronal part of the gutta-percha cone.
• The tip of the plugger is placed in the center of the
gutta-percha cone, heat is applied, and the plugger
is carefully pushed down the canal to the selected
depth. This should take 3 seconds.
• Then heat is then turned off and the plugger is re-
mained in place for a further 10 seconds.

6. • With fast motion, turn on the heat and withdraw the
plugger. A piece of gutta-percha will come along
with the plugger, and the apical piece remain in the
canal.
• The apical piece is compacted using conventional
hand plugger.
• The remaining part of the canal is either filled in the
same method until the canal is full, or back-filled
using other system such as injectable gutta-percha
technique:
• The a layer of RMGIC is placed and tooth is re-
stored.
ROTATING CONDENSER TECHNIQUE
In this technique an engine-driven compactor is placed
into the canal and rotated at 12000 rpm, which gener-
ate heat that plasticize and soften the gutta-percha. A
rotating stainless steel instrument is used to generate
this heat and compact gutta-percha laterally and apical-
ly. Although original devices are no longer made, other
similar devices such as Gutta-Condenser, Thermal Lat-
eral Condenser are available. Most of these devices are
made from Ni-Ti and rotated at 8000 rpm.
The technique in summary: a gutta-percha cone is fitted
into the canal and the the condenser is insert into the
canal alongside master gutta-percha cone and rotated
at 800 rpm. The generated heat will plasticize the gut-
ta-percha and compact it laterally and apically.
Concern has been found regarding the possibility of
apical extrusion of the plasticized gutta-percha and
modifications to the original technique has been sug-
gested. The modification involve lateral compaction of
gutta-percha master cone and a few accessory points,
which will seal the apical part of the canal, then the
condenser is introduced and rotated to fill the rest of
the canal. Additional cones are added to the canal and
plasticized if needed.
PRECOATED CARRIERS
In this technique a carrier made of plastic that is coat-
ed with gutta-percha is introduced into a softening ma-
chine and then it inserted into the canal. Most common
device is Thermafil.
It should be noted that this technique require canal
preparation with files of at least 0.04 taper. Canals pre-
pared with hand files of taper 0.02 will not work.
Procedure
• Dry the canal
• Use carrier verifier of estimated size and insert it to
the full working length and a radiograph is taken to
confirm the position.
Figure 3. Gutta-Condenser bur, which resemble inverted
Hedstorm file. It should be engine-driven at 8000 rpm
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7. • Coat the canal with sealer
• Coated carrier of the same size as verifier is insert-
ed in the conditioning oven for appropriate time
• The heated carrier is then inserted into the canal
shorter of the working length by 0.5 mm.
• After gutta-percha has been cooled, the carrier is
cut and condensed vertically. Additional gutta-per-
cha can be added if needed.
One modifications of this technique is to use cold
compaction for the apical part of the canal and then
using a coated carrier for the rest of the canal.
INJECTION DELIVERY SYSTEMS
In this technique the gutta-percha is heated in a spe-
cial device (gutta-percha gun) and delivered into the
canal as creamy softened gutta-percha. This tech-
nique require a very definitive apical stop, and the
possibility of apical extrusion is very high.
Some modification of this technique called sectional
injection technique, in which a piece of gutta-percha
is melted to a plugger of suitable size and then in-
troduced into the apical portion of the canal. Then
gutta-percha can be injected for the rest of the canal.
Injection delivery systems are very popular for
back-filling the middle and coronal portion following
warm vertical compaction or lateral compaction.
Commercially available injection delivery systems is
Obtura series.
Figure 4. Coated carrier and verifier along
each other
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8. SOLVENT-SOFTENED GUTTA-PERCHA
One technique is to fill the root canal with solution of
rosin in chloroform, and the master cone is seated into
the canal. Chloroform soften the surface of master cone
and made it swell, and the rosin act as a glue to make the
mass stick to the canal walls. Also some ready products
are available such as Kloroperka, and Chloro-percha.
Another technique is called chloroform dip technique.
In this technique, the apical 2-5 mm of the master cone
is dipped in chloroform for a few second and then with-
drawn. The cone is left to dry. Chloroform soften the
outer layer of master cone, and when seated into the
canal it take its shape.
SEALERS
Sealers are used to fill the space between obturation
mass and prepared dentinal wall.
Objective of using a sealer are:
• Cementing obturation material to the canal
• Filling the spaces between obturation material and
the canal
• Act as lubricant
• Act as antibacterial agent
Ideal properties of sealer are:
• Not irritating to periapical tissue
• Insoluble in tissue fluids
• Dimensionally stable
• Good sealing ability
• radiopaque
• bacteriostatic
• Good adhesion properties
• Ease of manipulation
• Non-staining to dentin
• Easily removed when necessary
Sealers that are available in use today:
• Zinc oxide-eugenol sealers
• Calcium hydroxide sealers
• Resin sealers
• Glass ionomer sealers
• Silicone-based sealers
Zinc oxide-eugenol sealers
• Most commonly used sealers
• Available products: Tubli-Seal, Roth Sealer, Pulp
Canal Sealer.
• Also modified products with extended working
time are also available
• They are porous and susceptible to dissolution in
presence of tissue fluids
• They are cytotoxic if extended beyond the apex,
and causes cellular response, although it is clinical-
ly insignificant.
Calcium hydroxide sealers
• Their sealing ability is similar to zinc oxide-euge-
nol sealers
• May be soluble in tissue fluids
• Available products are: Sealapex, Apexit Plus,
Acroseal
Resin-based Sealers
• Less popular than zinc oxide-eugenol sealer
• AH Plus product has good sealing ability, less cyto-
toxicity and low solubility
• EndoREZ product is recommended for use with
EndoREZ points, to increase bonding of obturation
mass to dentin
• Other available products are: Hybrid Root SEAL,
MetaSEAL
Glass Ionomer Sealers
• It has sealing ability similar to traditional sealers
• Activ GP product is used with Activ GP points
Silicone-based Sealers
• RoekoSeal product manufacturer claim this seal-
er expand slightly on setting, and is highly radi-
opaque, and has good sealing ability. However, no
difference were noted between this sealer and AH
Plus
• GuttaFlow product is also expandable slightly on
setting, and has less cytotoxicity than some other
sealers
REFERENCES
1. Harty’s Endodontics in Clinical Practice - Churchill
Livingstone; 6 edition (May 18, 2010)
2. Endodontology, Michael A. Baumann
3. Pocket Atlas of Endodontics
4. A Clinical Guide to Endodontics, P. Carrotte, Brit-
ish Dental Journal.