Obturation

Copyright (c) By Dr. Khin Swe Aye
Department of Conservative Dentistry
University of Dental Medicine, Yangon

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ROOT CANAL
OBTURATION
Khin Swe Aye
B.D.S., Dip.D.Sc., M.D.Sc., Dr.D.Sc., F.I.C.C.D.E
Department of Conservative Dentistry
University of Dental Medicine (Ygn)

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CONTENTS
I. Introduction
II. Criteria for Obturation
III. Obturation Materials
IV. Potential Causes of Failure
V. Obturation Techniques
VI. Coronal Seal

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I. Introduction
What is root canal obturation?
It is three-dimensionally filling of the entire
root canal system with biologically acceptable
materials.
Usually, the canal system is obturated with a
core material and minimal amount of a sealer.

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Introduction

5. 5
Introduction
Why is root canal obturated?
Following through cleaning and shaping, the
root canal system is obturated to provide the
system airtight seal.

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8. 8
Introduction
Obturation prevents:
the ingress of micro-organisms into the root
canal system by coronal leakage,
the multiplication of microorganisms
remaining in the root canal system,

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percolation of tissue fluid into pulp space via
apical foramina/lateral canals or furcal
canals,
bacterial percolation into the pulp canal
space via interconnections with the gingival
sulcus or periodontal pockets.

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II. Criteria for Obturation
The root canal can be obturated when:
There is an absence of pain and
swelling
There is no tenderness to percussion
There is no patent sinus tract
The canal is dry
The canal is odour-free
The canal has been medicated for at
least one week

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Patient Symptoms
•If the patient presents with severe symptoms
and the diagnosis is symptomatic (acute) apical
periodontitis or abscess, obturation is
contraindicated
•Painful irreversible pulpitis is a different
situation
Because the inflamed pulp (which is the pain
source) is to be removed, obturation may be
completed at the same appointment

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Pulp and Periapical Status
Vital Pulp
•If time permits, the procedure may be
completed in a single visit
Necrotic Pulp
•Without significant symptoms, obturation may be
completed during the same appointment
•Benefits of treating these patients in two visits??
•Multiple appointments related to healing of apical
pathosis
(CaOH2 Intra canal dressing)

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Criteria for Obturation
Obturation should not be carried out
immediately in the following situations:
In teeth with apical periodontitis (radiological
or symptomatic)
Teeth with excessive exudate
Teeth with purulent discharge
Root canal retreatment
Complex treatment such as perforation repair

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III. Obturation Materials
1.Core Obturation Material
2.Pastes (Semisolids)
3.Sealers

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1. Core Material
i. Gutta-Percha
ii. Resin
iii. Silver Points

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Gutta percha has been used to fill root canals
for over a century, and remains the material of
choice
(Hills Stopping Points)
i. Gutta-percha
Shapes
two basic shapes:
the “standardized” and the “conventional”

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Composition
Gutta-percha 19 – 20%
Zinc Oxide 59 – 75% for stiffness
Metal sulfate1.5 – 17% for radiopacity
Waxes/Resins1 - 4% for handling properties
Coloring agent < 1% for visual contrast

18. 18 Gutta-Percha points in ISO sizes (2%, 6%)

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Gutta-percha
Gutta percha manufactured to correspond to
the Greater Taper files (Dentsply), in tapers
0.06, 0.08, 0.10, 0.12.

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Gutta-percha
Accessory gutta percha points in sizes A-D.

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Gutta-percha
The ISO points are manufactured in a wide
range of sizes correspond to the hand files.

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Advantages
•plasticity
•relatively easy to manage and manipulate
•easy to remove from the canal
•relatively biocompatible

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Sealability
•without sealer, Gutta-Percha will not seal
Disadvantages

•lack of adhesion to dentin

•a slight elasticity, which causes a rebound and
pulling away from the canal walls
•Warmed gutta-percha shrinks during cooling

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ii. Resin
•Synthetic polyester resin–based polymers
•Core material is polycaprolactone with fillers of
bioactive glass and other components

•Used with a dual cured Bis-GMA resin sealer
and self-etching primer
( Monoblock, Swartz, 2006)

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Resin-based obturation system contains primer,
sealer, and cones. The cones resemble gutta-percha

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iii. Silver Points
•Designed to correspond to the last file size
used in preparation
•Because of the complexity of RCS, it is
impossible to prepare canals to a uniformly
round shape
no longer recommended as an obturating
material

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2. Pastes (Semisolid)
Major Disadvantages:
•lack of length control
•shrinkage
•toxicity of ingredients
•Voids
•no longer recommended

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Types
i. Zinc Oxide and Eugenol
• pure (no additives)
• with various additives (N2 or RC2B)
ii. Plastics
• a resin-based sealer
(AH26 and Diaket)
Techniques of Placement
•Injection
•Lentulo spiral

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3. Sealers
Root canal sealer is used to obliterate the
irregularities and voids between the root
canal filling material and the canal wall
A sealer improves the seal of the root canal
filling and should be antibacterial

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Types of Sealer
i. Zinc oxide and eugenol based sealer
(Grossman’s Formulation)
ii. Calcium hydroxide
(Sealapex - Kerr)
iii. Epoxy Resin
iv. Glass ionomer
v. Ceramic-Based Sealers

54. 54 ZOE based sealer

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Glass Ionomer
Advantages:
•Bonding to dentin seems to provide an
adequate apical and coronal seal
•Biocompatible
However, its hardness and insolubility make
retreatment and post space preparation more
difficult

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Glass ionomer–coated gutta-percha points
(A) are used in conjunction with a glass ionomer sealer (B)
to attempt to create a monoblock within the canal system

70. 70 Epoxy Resin sealer

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Epoxy Resin sealer

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Epoxy Resin Sealer

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•GuttaFlow is a cold fl
owable injection system
that combines a
silicone-based matrix
with fi nely ground
gutta-percha
• It is used in conjunction
with a master
guttapercha
point without the need
for compaction

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IV.Potential Causes of Failure
1.Apical Seal
2.Coronal Seal
3.Restoration
4.Lateral Seal
5.Overextension (Overfill)
a. Obturating Materials
b. Lack of Apical Seal Secondary to Overextension
6.Obturation Short of Apical Constriction (Underfill)
7.Vertical Root Fracture

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Vertical root fractures can occur with excessive
compaction forces

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V. Obturation Techniques
1. Cold lateral condensation
2. Warm lateral condensation
3. Warm vertical condensation
4. Thermocompaction (ultrasonic and mechanical)
5. Injection of thermoplasticized GP
6. Solvent-Softened Custom Cone
(E.g., Chloropercha)
7. Carrier-based GP
8. Sectional Obturation

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1. Cold Lateral Condensation
(1). Cone Fitting
A standardized g.p point of the same size as
the master apical file (final apical file) is
selected (Master Cone)
The point is then inserted into the canal, and
should exhibit 'tug-back' at a point 0.5-1.0 mm
short of the working length

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Cold Lateral Condensation
(2). Lateral Condensation
Dry the canal with paper points
Mix the sealer and coat the canal walls evenly
with hand file or lentulo spiral
Dip the master cone in the sealer and insert
into the canal
Insert finger spreader between the GP and the
canal wall
Push the spreader and rotate it back and forth
45 degree

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Cold Lateral Condensation
(3). Accessory g.p points placement
Withdraw the spreader
Choose the accessory point and insert into the
vacated space
Repeat this procedure until the canal is filled.
Remove the excess GP at the canal orifice with
heated instrument
Condense the top of GP vertically with a cold
plugger

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2. Warm Lateral Condensation
It is a variant of traditional lateral condensation

A heated instrument is introduced into a tooth
already obturated by lateral condensation to
soften the gutta-percha mass and enhance
adaptation to the internal anatomy of the canal

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An Endotec instrument used for warm
lateral condensation

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Warm Lateral Condensation
This technique is useful to increase the
adaptation and density of teeth obturated with
lateral condensation
It is especially indicated for teeth with internal
resorptive defects and C-shaped canals

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Warm Lateral Condensation
A case of internal resorption

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3. Warm Vertical Condensation
In 1967, Schilder advocated

as an alternative technique to cold lateral
condensation or silver points
The principal advantage;
its ability to adapt the warmed and softened g.p
to irregularities and accessory and lateral
canals within the r c system

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Schilder pluggers used for warm vertical condensation
(size 8 to size 12 with half sizes)

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The Touch-N-Heat is used in warm gutta-percha
techniques

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Warm Vertical Condensation
There are (3) phases;
(1). Cone fit
(2). Down pack
(3). Back fill

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Warm Vertical Condensation
Before r c filling,
Check
The completed
preparation should be
tapered
Keeping the apical
preparation as small as
practical prevents extrusion
of filling material

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Warm Vertical Condensation
Do
The System B tip is pre-
measured
It should fit passively
5-7 mm from the
working length
A rubber stop is used
to mark the length
against a reference point

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System B Unit
The System B heat
source is an electric
device that supplies
heat to a plugger on
demand

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System B plugger has been marked with a
rubber stop
Touching the spring on the handle causes the tip
to heat up instantly

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Warm Vertical Condensation
(1). Cone Fit
A tapered cone is selected
that corresponds to the
completed preparation
If the tip of the g.p point is
too small then it can be
trimmed with scissors
'Tug-back‘ should be felt
when the fit is correct

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If the tip of the g.p point is too small it
should be trimmed to correspond to the
master apical file

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Warm Vertical Condensation
A light coating of sealer
is placed on the walls of
the canal, using a hand
file, and onto the g.p
point

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Warm Vertical Condensation
(2). The down pack
The cone is cut off level with
the pulp floor using the
system B tip
Light pressure is applied with
a cold plugger
The activated System B tip is
plunged apically into the
g.p until the stopper is 2-3
mm short of the reference
point

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Warm Vertical Condensation
The wave of compaction
is continued without heat
until the rubber stop is at
the reference point
Apical pressure is applied
for 10 seconds as the
g.p cools

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Warm Vertical Condensation
A short burst of heat is
applied and the System
B tip is removed
A cold plugger is used to
compact the apical
segment of g.p

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Warm Vertical Condensation
(3). The Backfill
The coronal portion of the
canal is empty

It can be obturated using
small segments of heated
g.p

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Warm Vertical Condensation
When using the Obtura II
system, the tip should be
inserted gently into the
apical mass of g.p
before injecting
Light apical pressure
should be maintained as
the g.p is injected into the
root canal

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Obtura II System

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Warm Vertical Condensation
Alternatively, small
segments of a g.p
point can be placed in
the canal, heated with
the System B tip and
compacted using cold
Machtou pluggers

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Machtou pluggers are used to compact
the gutta percha following heating

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Warm Vertical Condensation
Each segment is compacted
vertically as it cools

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Warm Vertical Condensation
The canal is filled to
the level of the pulp
floor

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Disadvantages
Difficult to master and time consuming
Difficult to use in curved canals where the
straight, rigid pluggers are unable to
penetrate to the necessary depth
Enormous pressures are created in the apical
portion of the root, producing more fractures
than lateral condensation

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Disadvantages
To allow the rigid carriers to contact the gutta-
percha within 4 or 5 mm of the apex, the
canals must be prepared larger and more
tapered than in the lateral condensation
technique, requiring the removal of additional
dentin, which weakens the root

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C, A room
temperature
plugger is used to
compact the heated
gutta-percha
Warm vertical compaction of guttapercha
employs heat and various condensers
A, Nonstandard
cones are selected
and fit short of the
prepared length
because they more
closely replicate
the prepared canal
B, Heated pluggers
or spreaders are
used to apply heat
to the master cone
and remove the
excess coronal
material

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F, The heated
segment is
compacted
D, Apical
compaction is
complete
E, A gutta-percha
segment is placed
in the canal, and
heat is applied

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I, Completed
obturation
G, The process
is repeated for the
coronal portion of the
canal by placing and
heating a segment of
gutta-percha
H, A plugger is again
used to compact the
heated material

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4. Thermocompaction
(ultrasonic and mechanical)
This technique is also known as
“Continuous Wave Obturation.”
It is a modification of warm vertical compaction
introduced by Buchanan
This technique requires a smooth tapering
funnel, an apical constriction, and appropriate
master cone adaptation

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Thermocompaction (ultrasonic and
mechanical)
Applying a constant source of heat to a
prefitted g.p cone softens the g.p so the
clinician can apply hydraulic pressure in one
continuous motion
As the plugger moves apically, the cone
adaptation is more precise and the hydraulic
pressure increases, forcing the g.p into canal
irregularities and accessory canals

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Thermocompaction (ultrasonic and
mechanical)
The master cone is coated with sealer and
used to coat the canal walls
The System B heat source is set to 200° C
and placed in touch mode
Ensure that the heat is never activated for
more that 4 seconds
Pressure is maintained on the apical g.p
while the heat source is shut off for 5 to 10
seconds

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5. Injection of Thermoplasticized
Gutta-Percha
Instead of introducing g.p into the root canal
and applying heat to cause it to flow, the
material can be heated outside the tooth and
injected in a thermoplasticized state
Obtura II system is used in this technique

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Obtura II System

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Injection of Thermoplasticized
Gutta-Percha
Obtura system consists of a handheld gun
that contains a chamber surrounded by a
heating element into which pellets of gutta-
percha are loaded and heated
Silver needles are attached to deliver the
thermoplasticized material to the canal

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Injection of Thermoplasticized
Gutta-Percha
Prepares the canal in the same manner as for
lateral condensation
Because the needles are small and the
thermoplasticized material flows readily, do
not create too much flare in the preparation
The apical terminus must remain as small as
possible to prevent extrusion

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Note filling into the
resorptive space and
extrusion of the GP

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6. Solvent-Softened Custom Cone
Technique (E.g., Chloropercha)
It is a Custom-fitting Gutta Percha Cone
Occasionally the apical size of the prepared
root canal may be larger than a standardized
cone
In this case a customized gutta percha cone
will need to be formed
The chloroform dip technique is useful in this
situation

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Solvent-Softened Custom Cone
Technique (E.g., Chloropercha)
The tip is dipped in chloroform

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After the softened cone has
been tamped into the canal and
removed, it should show an
impression of the apical region

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7. Carrier-Based Gutta-Percha
Originally the gutta-percha carrier systems
(Thermafil, Dentsply, Tulsa Dental, Tulsa,
OK) were manufactured with a metal core to
which the manufacturer applied a coating of
gutta-percha
Later advances in the carrier systems include
the development of a plastic core coated
with alpha-phase gutta-percha and a
heating device that heats the carrier and
controls the temperature

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Carrier-Based Gutta-Percha
The Thermafil
oven with a
Thermafil
obturator

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Carrier-Based Gutta-Percha
A Thermafil obturator and appropriate
size verifier

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Carrier-Based Gutta-Percha
A size 50/.12 GT nickel-titanium file and
the corresponding GT obturator

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Carrier-Based Gutta-Percha
The carrier-based technique requires the use
of a sealer, and the removal of the smear
layer is recommended
Grossman formulation sealers or resin
sealers consistent with AH26 are acceptable
Tubliseal and Wach's Paste are not
recommended

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Carrier-Based Gutta-Percha
Clinical Procedure
Dry the canal and place a light coat of sealer
Set the rubber stop on the carrier shaft
Disinfect the carrier with 5.25% sodium
hypochlorite for 1 minute and rinsed in 70%
alcohol

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Carrier-Based Gutta-Percha
Place the carrier in the heating device
Heat the carrier to the appropriate temperature
(The operator has approximately 10 seconds to
retrieve the carrier and insert it into the canal.)
After waiting 2 to 4 minutes for the material to
set, section the carrier several millimeters
above the canal orifice

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Carrier-Based Gutta-Percha
If retreatment is required the plastic carrier
has a groove along its length to provide an
access point for placement of a file
Rotary .04 and .06 nickel-titanium files may
facilitate complete removal of the obturation
materials
When necessary, chloroform and hand files
can be used to remove the gutta-percha
surrounding the carrier

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Carrier-Based Gutta-Percha
The plastic carriers are composed of two
materials
Sizes up to 40 are manufactured from a liquid
crystal plastic
Sizes 40 to 90 are composed of polysulfone
polymer
Both have similar physical characteristics,
with the polysulfone carriers being
susceptible to dissolution in chloroform

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8. Sectional Obturation
•A recent innovation is a technique that uses special
devices and involves a two-phased sectional
approach
•A small apical segment of gutta-percha is placed
(“downpacked”) and followed by a backfilling of gutta-
percha
•This technique seems relatively fast and may prove
useful but requires more investigation

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-Carriers with apical plugs of
gutta-percha attached
- Once inserted into a canal
prepared using specially
designed rotary files, the carrier is
rotated in a counterclockwise
direction to separate the gutta-
percha from the carrier
-The canal is then backfi lled
using lateral or warm
compaction
- Carriers are also available with
resin plug

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VI. 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
Don’t forget to place a good and
reliable restoration after the
obturation

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