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Tooth Canal Obturation System
Nawaf Hazaymeh
Mohamad A. Zou'bi
Sun. 17-3-2013
6
In this lecture we will talk about a new topic which is Tooth Canal Obturation
System ……
When we said "Tooth Canal Obturation System" that’s mean we are dealing with
more than one canal (not only the straight canal we have also the lateral canal
and the accessory one) each one with different anatomy.
If we want to define our failures in the Root Canal treatment we will find that
Obturation is the most common cause of failure so it's considered as the most
important step in root canal treatment, so to achieve the success treatment we
need to do Obturation in a right way.
However there are many different other causes that lead to failure in root canal
treatment not only the obturation such as:
1) Loss of or inadequate coronal seal.
2) Inadequate débridement and disinfection.
3) Missed canals.
4) Vertical root fractures ( to avoid this in the lab Don’t push a big files inside the
canal because this may lead to root fracture, if it I the apical part it will lead to
apical fracture and if it in the coronal part it will lead to coronal tooth fracture
which is not treatable so then you will need to send your patient to the Oral
Surgery Department in the hospital )
5) Significant periodontal disease.
6) Coronal fractures.
7) Poor aseptic technique.
8) Procedural errors such as loss of length, ledging, zipping, and perforations.
So we need to avoid these causes in order to achieve a
successful treatment.
The objective of obturation is to create a complete seal along the length of the
root canal system from the coronal opening to the apical termination.
Complete seal mean that we need to obturate in a 3D seal of the canal system
for example for one canal we don’t seal just the mesiodistal dimension we need
other dimension to be included in the sealing process, and the root after
preparation it becomes like a conical shape or you need to be confined to the
anatomy of the root canal to maintain the root canal shape; so you need to
obdurate all the spaces in the root canal system and before that you need to
clean them and/or to shape them.
And we need to obdurate these canals from the coronal part down to the apical
part, so it's not only a coronal seal or just an apical seal it's a complete seal (from
the top to the apex).
Hint: you need to be confined to the canal; your seal only in the canals we don’t
need to go beyond the apex in order to achieve apical seal.
One of the major mistake dentist make during obturation is that they missed the
coronal part or the coronal restoration where mikroleakage will happen and by
that we will have a long term failure (not immediate failure like fracture or
perforation …etc).
Persistence or development of periapical pathosis may not be evident for months
or even years after treatment.( the cause is there but the symptom will appear
later on) Therefore recall evaluation to assess the response to treatment is
important. Obturation-related failures occur in different ways.
Now let's take a look at these radiographs…
In "A" radiograph if you look at the radiolucent area which is at the side of this
premolar {area inside the white circle} and its related to the apex; so this mean
there is a lateral canal which is infected and leads to this big radiolucent area and
after obturation using a specific technique the operator will success in obturating
this space which leads tl the healing of this radiolucent area.
Failure make also could happen due to overfilled or under filled roots as well as
missed root canal so you need to obdurate only the root canal system not less
not more.
When questions arise, such as “When is treatment to be completed? Is it time to
obturate? ;to answer these question first of all you need to look at the symptom
that the patient complaining of ,the following factors are considered: signs and
symptoms, pulp and periapical status, and difficulty of procedure. Combinations
of these factors affect decisions of finishing the obturation or the whole treatment
made about the number of appointments and timing of obturation.
Desirable Properties of Obturating Materials
Grossman suggested that the ideal obturant should do the following :
1• Be easily introduced into the canal.
" By that you can handle it and introduce it into the canal ".
2• Seal the canal laterally, as well as apically.
3• Not shrink after being inserted.
"We need it dimensionally stable, because as we said previously we need a
complete sealing or a 3D seal to the root canal system … therefore when it
shrinks this will cause a spaces where microorganisms can accumulate and
cause a harmful infection"
Pay attention that as we don’t need the obturant to shrinks, also we don’t need it
to expand because this will lead to produce pressure on the root canal walls
which may lead to fracture or continuous pressure.
4• Be impervious to moisture.
5• Be bactericidal or at least discourage bacterial growth.
"We don’t need these material to encourage the bacterial growth , we need it at
least to stop its growth"
6• Be radiopaque.
7• Not stain tooth structure.
8• Not irritate periapical tissues or affect tooth structure.
9• Be sterile or easily sterilized.
10• be easily removed from the root canal.
"Why we need to remove it?..
If failures happened and you need to retreat
this case you need to be able to remove this
material easily"
Note: At this time, no material satisfies
all these criteria.
The best material we have now is the "Gutta-
Percha" because it satisfies most of these
criteria, which consist mainly of :
zinc oxide up to ( 60 -70)%.
About (15-20)% gutta-percha which is a
naturally present material from certain trees.
Other materials ( which Dr didn’t mention them)
The gutta-percha has been made manufactured according to the need for them
(they made it cone shape to fit the shape of the root also to be easily inserted).
filling endodontic percha-Gutta
contain to found were points
-gutta 20% approximately
oxide zinc 66% (matrix), percha
metal heavy 11% (filler),
3% and ),(radiopacifier sulfates
resins and/or waxes
(plasticizer).
dental of Journal Reference:
research
http://jdr.sagepub.com/content/
54/5/921
-if we look at the top corner of it, it will represent the same size of your file so it
come with different colors each color represent the size of the file of its color, So
it’s a standard gutta –perha cones.
Ex: if you look at the red one it will represent file size 25 and so on
Types :
A. Standardized cone Nos. 15 to 40.
B. Standardized cones No. 0.06, taper sizes No. 15 to 40.
C. Standardized cones Protaper .
-We have also conventional gutta-percha cone which is use as accessory cones,
used in conjugation with the master cone, so first we need to choose the master
cone "standard" and do the obturation and then obturate the remaining of the
canal space with a conventional cone (accessory) .
Types: extra fine, fine fine, fine medium fine, medium, large, and extra large.
So first of all we need to look at the final file we prepared the apical part by it
(apical enlargement step),and then we choose a master cone to fit our canal
after preparation according to that final file size in order to create apical sealing,
and then obturate the remaining of the canal space with a conventional cone
(accessory).
However gutta-percha is not the only material used in root canal obturation we
have also:
Resin-based obturation system contains primer, sealer, and cones.
The cones resemble gutta-percha and can be placed using lateral or warm
vertical compaction, but till now there is no enough research on this material
compared to gutta-percha.
Pellets are available for thermoplastic injection.
silver cones are no longer recommended as an obturating material,
because it's hard to compact these material laterally ( it’s a metal ) and
difficult to be taken out during retreatment and the corrosion products
which may produced by time.
In order to have a complete seal of the canal we need to seal in between these
cones "gutta-percha" because no matter how much we compact it we will still
have spaces between them; so in order to seal these spaces between these
cones also the irregularities in the canal wall which we didn’t prepare it in a nice
and smooth way so because of this we need to use the Sealers.
Sealers:
A basic concept is that sealer is more important than the core obturating material.
Sealer accomplishes the objective of :
•providing a fluid-tight seal; the core occupies space, serving as a vehicle for the
sealer.
• Sealer must be used in conjunction with the obturating material, regardless of
the technique or material used.
This makes the physical properties and placement of the sealer important.
How to use the sealer?
We cover the master cone with the sealer material and then insert it into the dry
canal and try to touch the whole wall in the canal with this sealer and then as
previously mentioned insert the master cone followed by the accessory one using
the finger spreaders.
So what the technique should we use in obturation the root canal space?
The two traditional techniques are lateral and vertical compaction of gutta-
percha; seal ability is similar in both.
The choice is dictated primarily by preference and custom, although there may
be special situations indicating a particular use of each technique, Both must be
used with a sealer.
•More recent approaches have been introduced that depend on warming and
softening formulations of gutta-percha with special devices and instruments and
then placing the gutta-percha incrementally
1. Lateral compaction: widely used, using a finger spreader we will push the
gatta-percha cones to the side and keep on pushing these cones to the
same side through all the obturating procedure; if you start from mesial to
distal keep on compacting gutta-percha toward this side.
Indications for lateral condensation :
Lateral compaction of gutta-percha may be used in most situations,Exceptions
are
severely curved or abnormally shaped canal ,because you can't insert your
spreader to the full length so you will not be able to condensate laterally.
canals or those with gross irregularities such as internal resorption (appear
in radiograph like a circle inside the canal space, so no matter how much
force you applied to the lateral surface the cone will not fit the shape of the
empty space which is circular in shape).
-However, lateral compaction may be combined with other obturation
approaches. In general, if the situation is not amenable to lateral (or vertical, if
that is the usual approach) compaction, it is too difficult for the general
practitioner and the patient should be referred to an endodontist.
Advantages of lateral condensation :
•Lateral compaction is relatively uncomplicated, easy requires a simple
armamentarium, and seals and obturates as well as any other technique in
conventional situations.
A major advantage of lateral compaction over most other techniques is length
control, with an apical stop and with careful use of the spreader, the length of the
gutta-percha filling is managed well.
Additional advantages include ease of retreatment, adaptation to the canal walls,
positive dimensional stability, and the ability to prepare post space.
Disadvantages of lateral condensation:
• A disadvantage of lateral compaction is that the resultant obturation is a series
of sealer-welded cones and thus not a homogeneous mass. There are no other
major disadvantages to lateral compaction other than difficulties in obturating
severely curved canals, an open apex, and canals with internal resorptive
defects.
What is the technique for the lateral condensation:
The steps of lateral compaction:
A. The master cone is fitted.
B. A finger spreader or plugger is inserted, ideally to 1 to 2 mm of the
prepared length.
C. The spreader is rotated and removed, and an accessory cone is placed in
the space created.
D. The process is repeated.
First we need to clean and dry the canal by using a paper point then to apply the
gutta-percha using a finger spreader and then put the sealers to seal any
remaining spaces.
Now Doctor move to the other slide which is (obturation) and do a slide show
from slide (6-21) ,so please go back and see them I will type what he talked
about in a form of points.
You need to have a master cone that fits the full working length and slightly
resistant to withdrawn.
When you measure the length you can create a notch by the tweezer, you
hold the cone with the tweezer on the working length and squeeze it; this
will create an impression/mark which do the same function as the rubber
stopper in the file.
Hold it with the tweezer, place it in the canal space and check if it reach
the full working length , check also its resistant.
Take care that your spreader when you place it may push the master cone
further down( so be careful to this point in the lab)
Tug-back means resistant to withdrawn; to make sure about this point take
a radiograph and look at the tip of the gutta-percha if ht reach the full
working length.
Caught the master cone with a sealer and insert it to the canal to fill the
spaces and give you the desired retention.
There are many different ways for applying the sealer to the canal walls
,one of them is by
Using the "gutta-percha cone" itself, you caught the tip of the master cone
only (we call it the master point) and apply it, then caught the tip of the
other one and then the accessory and so on… other ways is to caught the
whole length of the master cone and apply it to the walls, some others
proffered to insert the sealers using the lentola spiral ( Dr said that he don’t
preferred using this procedure because this way will make the canal
flowed by the sealer and by this we will not have enough spaces for the
gutta-percha and the sealer may be dissolved later on if it exposed to
microleakage and leave space behind ,remember that the function of the
sealer is to seal the tight spaces that I can't seal it with the gutta-percha)
Place the finger spreader, now the question is to which point I'm allowed to
insert the spreader?
This will depend on the amount of length of adhesion of the gutta-percha to
the apical part, so the spreader may go to a length 1-3 mm less than the
working length, but if the gutta-percha master point is loose the spreader
may go all the way and maybe beyond the apex.
However the finger spreader has a rubber stopper as the file this will help
in indicating how much length we should go.
Hint: if your spreader goes to the same length after each insertion of a gutta-
percha cone then you should know that there is something wrong in your
work!! Because with each gutta-percha inserted it should obliterate part of the
apical part, so the spreader should reduce in length each time.
Hold the spreader in its place for 15 seconds to allow the gutta-percha to
adapt, twist and remove.
Fill the resulting space in your canal with a gutta-percha point matched to
the spreader used and coated in sealer.
Work quickly as the space will be lost due to elastic recoil of the gutta-
percha that already placed.
Repeat until the whole canal is filled, until the spreader is no longer goes
further than level with cementoenamel junction CEJ.
Take a final radiograph to check for quality of root filling after you obdurate
the whole canal.
Heat the plugger to the "red point heated" and cut the excess of gutta-
percha.
At which level you need to cut the gutta-percha?
Posterior at the orifice, anterior beyond the orifice for esthetic reason.
We need to do a Coronal seal by restoring the cavity; first we do lining by a
resin modified glass ionomer RMGI and then put a permanent filling.
What are the common problem we face it :
1- Unable to get the canal dry.
2- Gutta-percha point gets bent in the canal.
3- No tug-back achieved.
4- Gutta-percha point come out with the spreader.
5- Sealer pasts sets too quickly.
6- Excessive pressure can cause root fracture.
7- Final radiograph shows:
Root filling to be short
Root filling to be through the apex
Voids in the canal
2. Vertical compaction: we start from the apical part and go to the coronal
part of the crown.
Vertical compaction is also an effective technique; studies show its sealability is
comparable to that of lateral compaction.
Although vertical compaction is not widely taught in dental schools, the technique
is becoming more popular.
With the introduction of new devices and techniques, the warm vertical
compaction technique is somewhat more user friendly and is less time
consuming.
Technique
•The warm vertical compaction technique requires a heat source and various
sized pluggers for compaction of the thermoplasticized gutta-percha.
Thermoplasticized Injection:
•With this technique, specially formulated gutta-percha is warmed and then
injected into the prepared canal with a device that works like a caulking gun.
When used in conjunction with a sealer, thermoplasticized injection provides an
adequate seal. This technique is useful in special situations However, lack of
length control and shrinkage on cooling are disadvantages.
This is an internal resorption which we talked about previously..
Radiolucencies
•Voids within the body or at the interface of obturating material and dentin wall
represent incomplete obturation.
Density
•Material should be of uniform density from coronal to apical aspects.
The coronal region (and large canals) are more radiopaque than the apical
region because of differences in mass of material. The margins of gutta-percha
should be sharp and distinct, with no fuzziness, indicating close adaptation
Length
•The material should extend to the prepared length and be removed apical to the
gingival margin (anterior teeth) and orifices (posterior teeth).
Taper
•The gutta-percha should reflect the canal shape (i.e., it should be tapered from
coronal to apical regions). Taper need not be uniform but should be consistent.
Ideally, the apical region should taper nearly to a point unless the canal in this
region was not small before preparation.
•Restoration
•Whether permanent or temporary, the restoration should be contacting enough
dentin surfaces to ensure a coronal seal.
•Indications for the vertical condensation :
•vertical compaction can be used in the same situations as lateral compaction. It
is preferred in a few circumstances, such as with internal resorption and with root
end induction.
•Advantages of the vertical condensation:
•The principal advantage of vertical over lateral compaction is the ability to adapt
the warmed and softened gutta-percha to the irregular root canal system.
Disadvantages of the vertical condensation:
Disadvantages include difficulty of length control, a more complicated procedure,
and a larger assortment of required instruments. Also, a somewhat larger canal
preparation is necessary to allow manipulation of the instruments.
This is the last lecture in the midterm exam… and for the root canal preparation chapter there is a section about rotary instrumentation, this part will not be included in the exam.
-Dr didn't mention many things in the slides I tried my best to cover them in this lecture as much as I can, so please try to take a look at the slides. Forgive me for any mistake……
Done By:
Mohamad Al.zou'bi