Obturation of Root Canal - Brief Presentation

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. Obturation
of Root Canals

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2. Overview

g 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:

# To prevent microorganism from entering root canal
m 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

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3. Objectives of Obturation

# To prevent microorganisms which remain in the root canal
after preparation from proliferating and passing into

periapical area

m To seal the pulp chamber and root canal system from outer
oral environment

= To prevent passage of periapical exudate and microorganism
to the canals system

# To prevent gingival microorganism from passing into the
root canals via Lateral canals

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4. When to Obturate?

= The decision of single visit or multi-visit endodontic treatment
is controversial.

m 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
a No sign of sinus, fistula or abscess
= The canal is dry and free from necrotic tissue or pus

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5. Smear Layer

g 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

An image shows treated dentinal wall after application of
chelating agent. Notice the opened dentinal tubules that are
ready to be filled with sealer.

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6. Obturation Materials

The ideal properties of an obturating material are:

m Biocompatible

= Dimensionally stable

m Capable of sealing the canal laterally and apically
m Unaffected by tissue fluids and insoluble

m Bacteriostatic

m Radiopaque

m Easily removed from the canal if necessary.

= Do not stain the tooth

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7. Obturation Materials

The available obturation materials are:

= Gutta-percha

m MTA

= Hydrophilic polymer
= Resilon

Outdated materials are:
= Silver points

x Paste Fillers (Paraformaldehyde, resorcinol, etc.)

m Gutta-percha is the most commonly used one, and its
procedures will be described here.

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8. Gutta-Percha Obturation

m Gutta-percha is a natural rubber obtained from topical trees
of the sapotaceae family.

Gutta-percha points consists of:

m Gutta-percha 20%
m Zinc oxide 59%

u Various waxes, coloring agents, antioxidants, and metal
salts to provide radiopacity

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9. Gutta-Percha Obturation

Properties of gutta-percha points:

# Inert (biological inactive)

= Dimensionally stable

m Non-allergenic

m antibacterial

m Radiopaque

m compactable

u Softened by heat

m Softened by organic solvents

m Removable when needed

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10. Gutta-Percha Obturation

Methods of filling root canal with gutta-percha can be
classified into three groups:

= Cold gutta-percha
m Heat-softened gutta-percha
# Solvent-softened gutta-percha

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11. Cold Lateral Compaction Technique

= This technique is taught and practiced throughout the world.

m It is the technique of choice for many clinicians.

m It is fast and easy technique.

= Procedure in summary: After canal preparation, master cone
that matching the size of master apical file is used to fill the
canal. Then accessory points are compacted laterally using
finger or hand spreader.

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12. Cold Lateral Compaction Technique

Procedure in detail:

a Irrigate the canal and dry

m Select a master cone that is the same size as the master
apical file

m 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 1mm from the tip and reinsert, or choose Larger gutta-
percha point)

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13. Cold Lateral Compaction Technique

Continued:

# Select a finger spreader that reach to the full working
length to the apical stop

m Place spreader alongside the master point and compact
using firm apical pressure only.

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14. Cold Lateral Compaction Technique

Continued:

m Leave the spreader in place for 3 seconds (to create
deformation in the gutta-percha)

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15. Cold Lateral Compaction Technique

Continued:

= Select accessory points and dip them into the sealer and
insert them alongside master cone.

m Use spreader to compact accessory points laterally.

m Repeat this procedure by adding more accessory points
until the canal can not take any more points.

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17. Cold Lateral Compaction Technique

Continued:

m Cut excess gutta-percha using heated plugger.

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18. Cold Lateral Compaction Technique

Continued:

m Place Resin-modified glass ionomer cement and apply final
restoration

m Take a periapical radiograph for follow-up

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19. Cold Lateral Compaction Technique

The drawbacks of cold Lateral compaction technique are:

# Lateral canals are not filled with obturation material

It is difficult to impossible to do lateral compaction in
curved canals

g It can not be done in canal with wide apex, or canals that
lack an apical stop

The requirements of successful Lateral compaction are:
m Tapered canal preparation with an apical stop
u A well-fitting master gutta-percha cone
sa Spreader with appropriate size and shape
m Accessory points which match the dimensions of the
spreader
= An appropriate sealer

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20. Cold Lateral Compaction Technique

Lateral
compaction under [7
the microscope. —

Notice then
laterally
compacted cones.

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22. Accessory point
Masterpoint
Cement

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23. Solving some problems in Lateral Compaction

Gutta-percha cone reach the working Length but it is Loose:

m Sometimes there are some gutta-percha cones that are
malsized. It is a manufacturing error. So try another gutta-
percha of the same size.

m 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.

(— iraqi Dental Academy a @lraqiDental

24. Solving some problems in Lateral Compaction

Gutta-percha cone passes beyond working Length:

= This either results from improper apical stop, or gutta-
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
1mm from the tip of the canal until the cone fits the canal.

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25. Solving some problems in Lateral Compaction

Gutta-percha does not reach the working Length:

It is the most common situation. It can occur due to several

reasons:

u 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 insufficient
irrigation of the canal with copious sodium hypochlorite.
Blocked canals are difficult to clean. Recapitulation with
small files and passive ultrasonic irrigation might help.

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26. Heat-softened gutta-percha techniques

m When heat softened gutta-percha compacted into the canal,
it can flow in the Lateral canals, fins and ramifications. 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. Examples:
= Warm Vertical Compaction (Touch N’ heat, System B)
m Rotating Condenser (Gutta-Condenser)

m Extracanal heating techniques: it involves heating gutta-
percha outside the root canal. Examples:
m Precoated carriers (Thermafil)
= Thermoplastic delivery systems (Obtura Ill)

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27. Warm Vertical Compaction

m Also known as schilder's technique, and continuous wave
of compaction technique (with some modifications).

m This technique is considered the gold standard for
endodontic obturation.

= 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 apically. Then the rest
of the canal either filled with the same technique or filled
with back-filling (injectable gutta-percha technique).

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28. Warm Vertical Compaction

Procedure in detail:

m Fit a gutta-percha cone and mark it at the working length

m System-B will be used to heat gutta-percha cone inside the
Canal

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29. Warm Vertical Compaction

Continued:

m 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.

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30. Warm Vertical Compaction

Continued:
m Also select a conventional plugger to fit to the same distance

# Dry the canal with paper points

m 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.
g Insert gutta-percha cone to the full working Length.

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31. Warm Vertical Compaction

Continued:

m Set temperature in System-B to 200 Celsius and cut the
coronal part of the gutta-percha cone

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32. @ 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.

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33. Warm Vertical Compaction

Continued:

x Then heat is then turned off and the plugger is remained
in place for a further 10 seconds.

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34. = 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.

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35. Warm Vertical Compaction

Continued:

m The apical piece is compacted using conventional hand
plugger.

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36. = 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:

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37. Warm Vertical Compaction

Continued:

m obtura gun, used for back-backing. It heats gutta-percha cone
inside of its gun, then inject it as softened cream.

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38. Rotating Condenser Technique

= In this technique an engine-driven compactor is placed into
the canal and rotated at 12000 rpm, which generate 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 apically.

# Although original devices are no longer made, other similar
devices such as Gutta-Condenser, Thermal Lateral Condenser
are available. Most of these devices are made from Ni-Ti and
rotated at 8000 rpm.

m 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 gutta-percha and
compact it laterally and apically.

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39. Rotating Condenser Technique

= Concern has been found regarding the possibility of apical
extrusion of the plasticized gutta-percha and modifications
to the original technique has been suggested.

x 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.

gutta-condenser bur, which
resemble inverted Hedstorm
file. It should be

engine-driven at 8000 rpm.

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40. Precoated carrier

= In this technique a carrier made of plastic that is coated with
gutta-percha is introduced into a softening machine and then
it inserted into the canal.

= Most common device is Thermafil.

g It should be noted that this technique require canal
preparation with files of at least 0.04 taper. Canals prepared
with hand files of taper 0.02 will not work.

Procedure:

a 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.

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41. Precoated carrier

Continued:

coated carrier and
verifier along each
other

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42. Precoated carrier

TES.
Continued:
m Coat the canal with sealer

m Coated carrier of the same size as verifier is inserted in the
conditioning oven for appropriate time

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43. Precoated carrier
Continued: à

x The heated carrier is then inserted into the canal shorter of
the working Length by 0.5 mm.

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44. Precoated carrier
Continued:

m After gutta-percha has been cooled, the carrier is cut and
condensed vertically. Additional gutta-percha can be added
if needed.

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45. Precoated carrier

FES SE

Continued:

m 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.

[FF iraqi Dental Academy E) @lraqiDental

46. Injection delivery systems

ı In this technique the gutta-percha is heated in a special device
(gutta-percha gun) and delivered into the canal as creamy
softened gutta-percha.

= This technique require a very definitive apical stop, and the
possibility of apical extrusion is very high.

mg 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 introduced 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.

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47. back-filling using injection delivery systems

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48. Solvent-Softened Gutta-Percha

m 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.

m 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 withdrawn. The cone is
left to dry. Chloroform soften the outer Layer of master cone,
and when seated into the canal it take its shape.

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49. Sealers

m Sealers are used to fill the space between obturation mass
and prepared dentinal wall.

Objective of using a sealer are:

m Cementing obturation material to the canal

m Filling the spaces between obturation material
and the canal

m Act as Lubricant

m Act as antibacterial agent

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50. Sealers

Ideal properties of sealer are

@ Not irritating to periapical tissue
# Insoluble in tissue fluids

= Dimensionally stable

# Good sealing ability

m Radiopaque

m Bacteriostatic

= Good adhesion properties

x Ease of manipulation

# Non-staining to dentin

m Easily removed when necessary

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51. Sealers

Sealers that are available in use today:

m Zinc oxide-eugenol sealers
m Calcium hydroxide sealers
= Resin sealers

m Glass ionomer sealers

x Silicone-based sealers

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52. 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

x 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 clinically
insignificant

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53. Calcium Hydroxide Sealers

@ Their sealing ability is similar to zinc oxide-eugenol sealers
m May be soluble in tissue fluids
m Available products are: Sealapex, Apexit Plus, Acroseal

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54. Resin-based Sealers

m Less popular than zinc oxide-eugenol sealer

m AH Plus product has good sealing ability, less cytotoxicity
and Low solubility

m EndoREZ product is recommended for use with EndoREZ

points, to increase bonding of obturation mass to dentin

m Other available products are: Hybrid Root SEAL, MetaSEAL

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55. Glass lonomer Sealers

g It has sealing ability similar to traditional sealers

m Activ GP product is used with Activ GP points

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56. Silicone-based Sealers

m RoekoSeal product manufacturer claim this sealer expand
slightly on setting, and is highly radiopaque, 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

Ef iraqi Dental Academy @ @lraqiDental

57. References
= Harty's Endodontics in Clinical Practice - Churchill
Livingstone; 6 edition (May 18, 2010)
m Endodontology, Michael A. Baumann
m Pocket Atlas of Endodontics

# A Clinical Guide to Endodontics, P. Carrotte, British Dental
Journal.

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58. THANK YOU
+ EB

f Iraqi Dental Academ